Neoadjuvant therapies can result in pathologic complete response (pCR) in patients with breast cancer, which can be predictive of long-term outcomes. Patients with estrogen receptor positive (ER +) tumors may receive either neoadjuvant chemotherapy (NAC) or neoadjuvant endocrine therapy (NET). We sought to compare survival outcomes in those with non-metastatic ER + breast cancer who received NET or NAC and achieved pCR.

All patients diagnosed with ER + /HER2- stage I-III breast cancer, who received neoadjuvant systemic therapy followed by surgery, and achieved pCR, were selected from the National Cancer Database (NCDB, 2010-2021). The Kaplan-Meier method was used to estimate overall survival (OS), and log-rank tests were used to test for differences in OS. Cox Proportional Hazards models were used to estimate the association of NAC vs NET with OS, after adjustment for covariates.

3313 patients met eligibility criteria: 3148 received NAC and 165 NET. The median follow-up for the entire cohort was 82 months (95% CI 80.4-83.1). Patients who received NAC were significantly younger (median age: NAC 49y vs NET 64y; p < 0.001), more likely to have a comorbidity score of 0 (NAC 89.3% vs NET 81.2%, p = 0.004), and more likely to have private insurance (NAC 68.9% vs NET 44.2%, p < 0.001). There were no significant differences between the NAC and NET patients based on race and ethnicity, income, education, or community type (all p > 0.05). The NAC treated patients were more likely to have larger tumors [median tumor size (IQR): NAC 3 cm (2.0-4.3) vs NET 1.3 cm (0.7-2.8); p < 0.001)], ductal histology (NAC 92.6% vs 81.2%, p < 0.001), and grade 3 tumors (NAC 70.2% vs 10.3%, p < 0.001). In the unadjusted Kaplan-Meier analysis, there was no significant difference in OS between NAC vs NET [5-year OS: NAC 0.935 vs NET 0.916; p = 0.08]. After adjustment for demographics, disease characteristics, and treatments, there remained no association between OS and study group (NAC vs NET; p = 0.63).

Patients with ER + /HER2- early-stage breast cancer who achieved pCR had similar OS, regardless of whether they received NAC or NET. As such, pCR appears to have similar prognostic value irrespective of the type of systemic therapy used to obtain this favorable outcome.

Human epidermal growth factor receptor 2 (HER2; encoded by ERBB2) testing has been a cornerstone of patient selection for HER2-targeted therapies, principally in breast cancer but also in several other solid tumours. Since the introduction of HercepTest as the original companion diagnostic for trastuzumab, HER2 assessment methods have evolved substantially, incorporating various testing modalities, from western blots, immunohistochemistry and fluorescence in situ hybridization, to early chromogenic quantitative methods and, probably in the future, fully quantitative methods. The advent of highly effective HER2-targeted antibody-drug conjugates with clinical activity at low levels of HER2 expression, such as trastuzumab deruxtecan, has necessitated the re-evaluation of HER2 testing, particularly for HER2-low tumours. In this Review, we provide an in-depth overview of the evolution of HER2 testing, the current clinical guidelines for HER2 testing across various solid tumours, challenges associated with current testing methodologies and the emerging potential of quantitative techniques. We discuss the importance of accurately defining HER2-low expression for therapeutic decision-making and how newer diagnostic approaches, such as quantitative immunofluorescence and RNA-based assays, might address the limitations of traditional immunohistochemistry-based methods. As the use of HER2-targeted therapies continues to expand to a wider range of tumour types, ensuring the precision and accuracy of HER2 testing will be crucial for guiding treatment strategies and improving patient outcomes.

The assessment of estrogen receptor (ER) expression in breast cancer, has traditionally been performed using ligand-binding assays, followed by immunohistochemistry, and is widely used to predict tumor response to endocrine therapy. ER-low positive breast cancer, formally defined in the 2020 ASCO/CAP testing guidelines, represents a small subset of invasive breast cancers characterized by 1 %-10 % of ER staining. Emerging evidence suggests that ER-low positive tumors constitute a heterogeneous group in terms of clinicopathologic features, molecular profiles, prognosis, and responsiveness to endocrine therapy. These tumors frequently behave more like ER-negative cancers, often displaying a more aggressive clinical course compared to classic ER-positive tumors. The clinical benefit of endocrine therapy in this subset remains uncertain, posing a significant challenge in determining the optimal treatment strategies. This review offers both a historical perspective and a comprehensive, up-to-date analysis of recent advancements in the understanding of ER-low positive breast cancer, with a focus on tumor biology, pathological evaluation, and clinical implications.

Despite that many oral SERDs have been reported in the literature, most of them do not have adequate CNS penetration. Here, we report our efforts in discovering brain penetrant oral SERDs to address the unmet medical need for Breast Cancer patients with brain metastasis (BCBM). Our strategy to convert the acrylic acid-containing motif of ZN-c5 to a basic amine-containing tail resulted in compounds with much improved brain penetration and excellent ER degradation activity. Further optimization led to the discovery of compound 5 with excellent in vitro and in vivo efficacy. Compound 5 showed good in vitro ADME properties, good oral bioavailability in mouse, rat, and dog, as well as superior brain penetration, which translated into excellent efficacy in multiple brain metastasis breast cancer mouse models.

This article is a review of the characteristics of bilateral breast cancer (BBC). Synchronous bilateral breast cancer (SBBC) and metachronous bilateral breast cancer (MBBC) account for 2.9-3.9% and 4.1-4.6% of all new breast cancer cases, respectively. The risk factors for SBBC include older patient age and lobular histology. On the other hand, younger age, lobular histology, and positive family history (or genetic factors) are the risk factors for MBBC. Contralateral prophylactic mastectomy in patients with mutations in the BRCA1/2 genes has been reported to increase survival rates. The prognosis of patients with SBBC is worse than the prognosis of patients with unilateral breast cancer (UBC). The prognosis of patients with MBBC compared to patients with UBC remains undetermined because the ages of patients and the intervals between the occurrence of two primary breast cancers appear to have a major impact on survival outcomes. The differences between SBBC and MBBC need clarification to increase our understanding of BBCs.

To evaluate whether HER2 (human epidermal growth factor receptor 2) (2+)/SISH (silver-enhanced in situ hybridization)+ and HER2 (3+) breast cancers exhibit distinct imaging characteristics on pre-treatment MRI and assess differences in pCR (pathologic complete response) prediction accuracy on post-treatment MRI, considering interobserver variability.

This retrospective study included 301 HER2-positive breast cancer patients (mean age, 54 ± 10 years) who underwent NAC and surgery. Pre-treatment MRI features were analyzed in consensus. Two radiologists independently assessed post-treatment MRI for shrinkage patterns and response according to RECIST v1.1, further categorizing complete responses into rCR (radiologic complete response) and near-rCR. Interobserver agreement was measured (Cohen's kappa), and pCR was defined as no residual invasive or in situ tumor in the breast (ypT0) on the final pathology report. Sensitivity, specificity, and AUC were used to evaluate pCR prediction.

Fifty-four patients had HER2 (2+)/SISH+ and 247 had HER2 (3+) tumors. pCR rates were significantly higher in HER2 (3+) (58.7% vs. 18.5%, p < 0.001). On pre-treatment MRI, HER2 (2+)/SISH+ tumors more often appeared as single masses, while HER2 (3+) tumors showed more NME (non-mass enhancement) (44.5% vs. 16.7%, p < 0.001) and mass with NME (33.6% vs. 9.3%, p = 0.005). Post-treatment MRI showed simple concentric shrinkage in HER2 (2+)/SISH+ and no enhancement in HER2 (3+). Agreement was moderate (κ = 0.541-0.588). For pCR prediction, rCR alone yielded AUCs ranging from 0.659 to 0.756. Adding near-rCR improved specificity but reduced sensitivity, with a significant AUC increase for one reader (p = 0.011).

Pre-treatment MRI revealed distinct imaging characteristics between subgroups. While pCR rates were higher in HER2 (3+), MRI-based pCR prediction showed similar performance, though near-rCR reduced sensitivity.

Estrogen receptor (ER) expression levels in breast cancer tissue predict the efficacy of endocrine therapy and the prognosis of breast cancer patients. Recently, it was reported that the prognosis of patients with ER-low-positive breast cancer was similar to that of ER-negative patients. This study aimed to investigate how ER expression levels impact the prognosis of patients with human epidermal growth factor receptor 2 (HER2)-negative early breast cancer undergoing long-term follow-up.

The correlation between ER expression levels and prognosis was retrospectively evaluated in a cohort of 3091 consecutive patients with HER2-negative early breast cancer who were treated at our institute between 1981 and 2022. The median follow-up period was 85.2 (range 0-480) months. The proportion of ER-expressing cells in breast cancer tissues was assessed by immunohistochemistry and used to classify patients into four categories: ER negative (<1%), ER-low positive (1% ≤ ER < 10%), ER-intermediate positive (10% ≤ ER < 2/3), and ER-high positive (≥2/3).

Patients with ER-intermediate-positive breast cancer had a prognosis similar to that of patients with ER-low-positive or ER-negative disease. By contrast, patients with ER-high-positive breast cancer had significantly longer disease-free survival (DFS) and overall survival (OS) times than the other groups. Multivariate analysis demonstrated that ER-intermediate positivity was an independent factor for poor prognosis for both DFS and OS in patients with HER2-negative early breast cancer. The distributions of tumor grades 1, 2, and 3 were nearly equal among the ER-intermediate-positive patients, whereas more than half of patients with ER-high-positive breast cancer had grade 1 tumors. By analyzing changes in prognosis over time, we found that the prognosis of patients with ER-high-positive breast cancer markedly improved over three decades, while that of patients with ER-intermediate-positive disease did not.

Patients with ER-intermediate-positive breast cancer differ from patients with ER-high-positive breast cancer, suggesting that the treatment of ER-positive breast cancer patients should be tailored based on ER expression levels.

Therapeutic efficacy of human endometrial stem cells (hEnSCs) encapsulated in hyaluronic acid (HA)-based microcapsules for cardiac regeneration in a rat model of MI is investigated. Cell-enclosed microcapsules were made by loading hEnSCs within hydrogel membrane produced from modified HA possessing phenolic hydroxyl moieties (HA-Ph). The hEnSC-loaded HA-Ph microcapsules (≈150 μm) injected intramyocardially into the peri-infarct area post-MI. The encapsulated cells showed mechanical stability and >87 % cell viability with cellular aggregation in size of about 100 μm until 7 days of culture. Transthoracic echocardiography evaluation indicated a significant increase in ejection fraction in encapsulated cells, compared to the other groups. Histological investigation of fibrosis and scar area by Masson trichrome and hematoxylin and eosin (H&E) staining illustrated less fibrosis and scarring area in the encapsulated cell group compared with the other groups. Furthermore, the cell-laden microcapsules significantly enhance expression intensities of actin and troponin as well as vascular endothelial-specific marker, all of which promote cardiac functions and contribute to a better therapeutic effect than the free-cell injection group in a rat model of MI. Our findings demonstrated that both hEnSCs and specifically hEnSC-loaded HA-based hydrogel vehicle can provide a promising novel therapy for functional restoration in MI instances.

Resistance to endocrine therapy (ET) is common in estrogen receptor (ER) positive breast cancer. Multiple studies have demonstrated that upregulation of MAPK signaling pathways contributes to ET resistance. Herein we show that vandetanib treatment enhances sensitivity to ET in ET-sensitive and -resistant ER+ breast cancer models. Vandetanib treatment alters the gene expression program of ER+ breast cancer cells resulting in a less proliferative and more estrogen responsive Luminal-A like character. Tyrosine kinase network reprogramming was assessed using multiplexed kinase inhibitor beads-mass spectrometry (MIB/MS) assay to identify adaptive resistance mechanisms to vandetanib treatment, including upregulation of HER2 activity. Co-treatment to inhibit HER2 with lapatinib enhanced sensitivity to vandetanib, demonstrating biologic activity of HER2 upregulation. Using a CRISPR knockout model, we demonstrate that vandetanib effects are partially mediated by RET receptor tyrosine kinase. Finally, we use our operating room-to-laboratory assay that measures drug response in individual primary tumor cells in short term cultures to demonstrate conserved gene expression changes, including increased HER2 activity signatures, in vandetanib treated cells, and identify features associated with vandetanib response. These results support future investigation of RET targeting strategies considering reprogrammed networks, such as activated HER2, in patients with ET resistant ER+ breast cancer.

Neoadjuvant pembrolizumab plus chemotherapy and adjuvant pembrolizumab have been established as the optimal systemic therapies for patients with early stage triple-negative breast cancer (TNBC); however, their efficacy and feasibility in the Japanese population remain unexplored.

This study included patients with early stage TNBC or low estrogen receptor (ER) positivity (1-9%) with human epidermal growth factor receptor type 2- (HER2-) negative breast cancer who received neoadjuvant pembrolizumab plus chemotherapy from October 2022 at Cancer Institute Hospital of Japanese Foundation for Cancer Research. Information regarding clinicopathological features, systemic therapy, treatment outcomes, and adverse events of patients who underwent surgery by February 2024 was retrospectively collected.

Overall, 69 patients received neoadjuvant pembrolizumab plus carboplatin and paclitaxel therapy, and 46 underwent surgery by February 2024. The median age of the patients was 53.5 years, and 80.4% and 19.6% had stage II and III disease, respectively. TNBC and ER-low HER2-negative breast cancer accounted for 82.6% and 17.4% cases, respectively. Overall pathological complete response rate was 56.5%, with 87.5% in patients with ER-low HER2-negative tumors. The completion rates for neoadjuvant pembrolizumab, chemotherapy, and pembrolizumab plus chemotherapy were 65.2%, 56.5%, and 52.2%, respectively. Furthermore, 80.4% and 15.2% of patients experienced grade 3 or higher treatment-related adverse events and immune-related adverse events, respectively, and 34% experienced unexpected hospitalization during neoadjuvant treatment.

The efficacy and safety profiles of neoadjuvant pembrolizumab plus chemotherapy in the Japanese population are consistent with previous reports. This regimen may have therapeutic potential against ER-low HER2-negative tumors and TNBC.

Breast cancer is the most common malignancy in women of reproductive age and chemotherapy protocols impair fertility, frequently necessitating fertility preservation (FP) referral. Embryo, oocyte, or ovarian tissue cryopreservation are established FP modalities in women with breast cancer but there are few data on their uptake over time. In this study our aim was to determine the regional time trends and utility differences for fertility preservation methods of reproductive tissue cryopreservation.

This multicenter study included 1623 women diagnosed with breast cancer from 7 tertiary centers in 6 countries (Brazil, Italy, Scotland, South Korea, Turkey, USA). Participant centers provided the details of FP cryopreservation approaches broken down annually from 2012 to 2021. Women with newly diagnosed breast cancer, aged 18-45 years who were referred for FP at participating centers and had normal ovarian function at the time were included.

We found a mean increase of 7% per year (P = .002, adjusting for centers) in the number of women referred for FP. Of those who were referred (n = 1623), a mean 38.7% underwent FP (n = 629), with a range of 12% in South Korea) to 95% in Brazil. The number of women undergoing ovarian stimulation for FP continually increased until 2021, with oocyte cryopreservation being the most common procedure throughout the study period (P = .014 for time trend). The proportion of random start ovarian stimulation cycles increased each year from 58.3% in 2012 to 86.8% in 2021, (P = .005 for time trend, and P = .04 for 2012 vs. 2021).

The utility of FP has steadily increased for young women with breast cancer over the last decade, although regional differences significantly influence FP practices. The findings of our study could have value for policy making in FP care for young women with breast cancer at the local, regional, or global level.

Immunohistochemistry (IHC) is crucial for determining cancer treatments. We previously developed a rapid IHC method and have now developed a fully automated rapid IHC stainer (R-Auto). This study aimed to evaluate the clinical reliability of the R-Auto protocol for staining estrogen receptors (ERs) in breast cancer specimens and evaluate the staining performance.

Between January 2015 and June 2020, 188 surgical specimens collected from breast cancer patients treated at our hospital were evaluated via ER staining using R-Auto, conventional manual IHC, and a commercial autostainer. The specimens were scored using Allred scores, after which the staining results were compared between R-Auto and conventional IHC or the commercial autostainer. Weighted kappa coefficients and AC1 statistics were used to assess the agreement between the methods.

The AC1 statistic for comparison between R-Auto and conventional IHC was 0.9490 (0.9139-0.9841), with a 95.7% agreement rate, and that for comparison between R-Auto and the commercial autostainer was 0.9095 (0.8620-0.9570), with a 92.6% agreement. There was, thus, substantial agreement between R-Auto and both conventional IHC and the commercial autostainer. However, R-Auto shortened the time required for IHC from 209 min with conventional IHC to 121 min.

R-Auto enables a good staining performance in a shorter time with less effort.

Combination chemotherapy remains essential for clinical management of triple-negative breast cancer (TNBC). Consequently, responses to multiple single agents cannot be delineated at the single patient level, even though some patients might not require all drugs in the combination. Herein, we conduct multi-omic analyses of orthotopic TNBC patient-derived xenografts (PDXs) treated with single agent carboplatin, docetaxel, or the combination. Combination responses were usually no better than the best single agent, with enhanced response in only ~13% of PDX, and apparent antagonism in a comparable percentage. Single-omic comparisons showed largely non-overlapping results between genes associated with single agent and combination treatments that could be validated in independent patient cohorts. Multi-omic analyses of PDXs identified agent-specific biomarkers/biomarker combinations, nominating high Cytokeratin-5 (KRT5) as a general marker of responsiveness. Notably, integrating proteomic with transcriptomic data improved predictive modeling of pathologic complete response to combination chemotherapy. PDXs refractory to all treatments were enriched for signatures of dysregulated mitochondrial function. Targeting this process indirectly in a PDX with HDAC inhibition plus chemotherapy in vivo overcomes chemoresistance. These results suggest possible resistance mechanisms and therapeutic strategies in TNBC to overcome chemoresistance, and potentially allow optimization of chemotherapeutic regimens.

There has been over 130 years of research into the treatment of breast cancer using approaches that target oestrogen receptor signalling. Here, we summarise the development of the key pillars of such endocrine therapy, namely, oestrogen deprivation, achieved through ovarian suppression and/or aromatase inhibition, and oestrogen receptor blockade, through selective oestrogen receptor modulators, downregulators and novel compounds entering early phase development. The translation of these compounds from advanced to early breast cancer settings is discussed with a focus on the placebo-controlled breast cancer prevention studies to most accurately describe the side effect profiles of the main approaches.

Laboratories performing predictive marker testing for breast carcinoma are encouraged to compare patient results to published benchmarks.

To collect expression rates for estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) in invasive breast carcinoma from multiple laboratories.

Participants submitted data from up to 50 primary cases during the study period. Participants reported ER, PgR, and HER2 results in addition to demographic and histologic information. Participants also provided annual institution-level expression rates.

A total of 21 institutions submitted data for 687 cases. Aggregate positivity rates for ER and PgR were 85.6% and 75.1%, respectively. Receptor positivity rates were higher in well-differentiated (grade 1) tumors (ER, 97.4%; PgR, 88.0%) compared with moderately differentiated (grade 2) tumors (ER, 92.4%; PgR, 84.0%) and poorly differentiated (grade 3) tumors (ER, 61.8%; PgR, 48.0%). Expression rates were higher in postmenopausal women (ER, 87.2%) than premenopausal women (ER, 79.6%) and higher in lobular carcinomas (ER, 98.7%; PgR, 85.3%) than ductal carcinomas (ER, 84.1%; PgR, 74.5%). The aggregate HER2 positivity (score 3+) rate was 9.0%. The aggregate HER2 equivocal (score 2+) rate was 14.5%. Of 81 equivocal (score 2+) cases, 70 (86.4%) were nonamplified.

The data from this study provide multi-institutional benchmark data to assist laboratories performing periodic comparisons as part of a quality management program. Overall expression rates were generally similar to those of other published reports, with the exception of the ER-negative and HER2-positive rates, both of which were somewhat lower.

Cancer stem cells (CSC) are a small number of tumour propagating cells present in the bulk of tumour cells. Expression of biological markers for CSCs viz. cluster of differentiation 24 and 44 (CD24, CD44) and aldehyde dehyodeganse 1 (ALDH1) imply aggressive tumour cell behaviour and poorer outcome, particularly in breast cancer. N = 75 Tumor tissue samples from enrolled breast cancer patients were obtained and subjected to histopathological examination and immunohistochemistry (IHC) after informed consent from patients. In addition to the estrogen receptor, progesterone receptor, Her2 neu receptor, and Ki67 index; IHC was also performed for CD24, CD44 and ALDH1A3 expression. These markers' positivity was correlated with clinical parameters, therapy response and metastasis prognostication. Most patients had higher tumor stage and high nodal burden (81.3% with node positivity; N1-68%, N2 -6.6%, N3-6.6%). Study showed significant association of CD24-/CD44 + group (p = 0.021) with distant metastasis and significant association of CD24-/CD44 + /ALDH1A3 + (p = 0.008) with higher stage (T4 stage). Tumor tissues expressing CD24-/CD44 + /ALDH1A3 + group (p = 0.010) and CD24 + /CD44 + / ALDH1A3 + (p = 0.010) were significantly associated with poor response to treatment. The correlation of CD24-/CD44 + was also statistically significant (p = 0.009). Positive expression of either CD24 and/or CD44 presented with aggressive disease, larger tumours and heavy nodal burden at a younger age. Additionally, ALDH1A3 positivity signified higher metastasis rates. CD24-/CD44 + /ALDH1A3 + and CD24 + /CD44 + / ALDH1A3 + correlated with greater chances of distant metastasis, aggressive disease, limited response to chemotherapy and poorer prognosis. Thus, these observations establish the role of these CSC phenotypes as important factors for prognostic outcomes and predictors of adverse outcomes. CD24-/CD44 + /ALDH1A3 + expression could serve as an important prognostic marker and predictor of adverse outcomes in Indian breast cancer tumour biology.

Patients with locally advanced rectal cancer often require neoadjuvant chemoradiation therapy to downstage the disease, but the response is variable with no predictive biomarkers. We have previously revealed through proteomic profiling that myoferlin is associated with response to radiation therapy. The aims of this study were to further validate this finding and explore the potential for myoferlin to act as a prognostic and/or therapeutic target.

Immunohistochemical analysis of a tissue microarray (TMA) for 111 patients was used to validate the initial proteomic findings. Manipulation of myoferlin was achieved using small interfering RNA, a small molecular inhibitor (wj460), and a CRISPR-Cas9 knockout cell line. Radiosensitization after treatment was assessed using 2-dimensional clonogenic assays, 3-dimensional spheroid models, and patient-derived organoids. Underlying mechanisms were investigated using electrophoresis, immunofluorescence, and immunoblotting.

Analysis of both the diagnostic biopsy and tumor resection samples confirmed that low myoferlin expression correlated with a good response to neoadjuvant long-course chemoradiation therapy. High myoferlin expression was associated with spread to local lymph nodes and worse 5-year survival (P = .01; hazard ratio, 3.5; 95% CI, 1.27-10.04). This was externally validated using the Stratification in Colorectal Cancer database. Quantification of myoferlin using immunoblotting in immortalized colorectal cancer cell lines and organoids demonstrated that high myoferlin expression was associated with increased radioresistance. Biological and pharmacologic manipulation of myoferlin resulted in significantly increased radiosensitivity across all cell lines in 2-dimensional and 3-dimensional models. After irradiation, myoferlin knockdown cells had a significantly impaired ability to repair DNA double-strand breaks. This appeared to be mediated via nonhomologous end-joining.

We have confirmed that high expression of myoferlin in rectal cancer is associated with poor response to neoadjuvant therapy and worse long-term survival. Furthermore, the manipulation of myoferlin led to increased radiosensitivity in vitro. This suggests that myoferlin could be targeted to enhance the sensitivity of patients with rectal cancer to radiation therapy, and further work is required.

As molecular imaging use expands for patients with breast cancer, it is important for breast radiologists to have a basic understanding of molecular imaging, including PET. Although breast radiologists may not directly interpret such studies, basic knowledge of molecular imaging will enable the radiologist to better direct diagnostic workup of patients as well as discuss diagnostic imaging with the patient and other treating physicians. Several new tracers are now available to complement imaging glucose metabolism with FDG. Because it provides a noninvasive assessment of disease status across the whole body, PET offers specific advantages over tissue-based assays. Paired with targeted therapy, molecular imaging has the potential to guide personalized treatment of breast cancer, including guiding dosing during drug trials as well as predicting and assessing clinical response. This review discusses the current established applications of FDG, which remains the most widely used PET radiotracer for malignancy, including breast cancer, and highlights potential areas for expanded use based on recent research. It also summarizes research to date on the U.S. Food and Drug Administration (FDA)-approved PET tracer 16α-18F-fluoro-17β-estradiol (FES), which targets ER, including the current guidelines from the Society of Nuclear Medicine and Molecular Imaging on the appropriate use of FES-PET/CT for breast cancer as well as areas of active investigation for other potential applications. Finally, the review highlights several of the most promising novel PET tracers that are poised for clinical translation in the near future.

Use of fine-needle aspiration biopsy (FNAB) specimens on Xpert Breast Cancer STRAT4 Assay (STRAT4; Cepheid, Sunnyvale, CA, USA), a CE-marked in-vitro diagnostic medical device, could potentially increase access to breast cancer biomarker testing in resource-constrained settings. We aimed to assess the performance of a research use-only version of STRAT4 using FNAB specimens in Tanzania.

In this prospective diagnostic accuracy study, patients aged 18 years or older with palpable breast masses presenting to the FNAB Clinic at Muhimbili National Hospital (Dar es Salaam, Tanzania) were recruited consecutively. Patients who were pregnant, lactating, or had a previous diagnosis of breast cancer were excluded. STRAT4 testing was performed on off-label FNAB samples using four protocols: the 1 × protocol (using the standard lysate method) on FNAB smears (1 × FNAB), quick lysis and Maui protocols (both on FNAB smears), and the 1 × protocol on formalin-fixed paraffin-embedded (FFPE) cell block material (1 × cell block). For 1 × FNAB and 1 × cell block, tissue was processed using FFPE lysis reagent, incubated at 80°C with proteinase K, and followed by addition of 95% or higher ethanol. Quick lysis was processed using FFPE lysis reagent and 95% or higher ethanol, whereas Maui was processed using a proprietary research-use only lysis reagent. The primary outcomes were overall concordance, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of STRAT4 as compared with immunohistochemistry or immunohistochemistry plus fluorescence in-situ hybridisation performed on cell blocks using clinically validated protocols in a Clinical Laboratory Improvement Amendments-accredited laboratory at the University of California, San Francisco (San Francisco, CA, USA).

Between Nov 29, 2017, and Dec 17, 2020, 208 patients were enrolled. Of 208 cases, 51 (25%) were excluded from analysis because of insufficient tissue in the cell block or absent cell blocks, leaving 157 participants (all female) for analysis. For oestrogen receptor, 1 × FNAB had the best performance, with an overall concordance of 95% (95% CI 90-100), sensitivity of 94% (85-100), specificity of 97% (90-100), and AUC of 0·96 (0·81-1·00). For progesterone receptor, 1 × cell block had the best overall performance (overall concordance 89% [95% CI 84-95], sensitivity 91% [82-99], and specificity 89% [81-97], with an AUC of 0·93 [0·89-0·99]) and 1 × FNAB performed the best among the smear protocols, with a concordance of 84% (95% CI 74-93), sensitivity of 63% (43-82), specificity of 97% (92-100), and AUC of 0·91 (0·72-0·97). For HER2, Maui had the highest agreement, with an overall concordance of 93% (95% CI 89-98), sensitivity of 96% (88-100), specificity of 92% (87-98), and AUC of 0·95 (0·98-1·00). For Ki67, Maui had the best performance of smear protocols, with a concordance of 73% (95% CI 64-82), sensitivity of 70% (58-81), specificity of 81% (66-96), and AUC of 0·80 (0·54-0·82).

Processing FNAB samples with STRAT4 is feasible in Tanzania, and performance for the oestrogen receptor is robust. Further optimisation of STRAT4 for FNAB has the potential to improve timely access to breast cancer diagnostics in resource-constrained settings.

US National Institutes of Health; UCSF Global Cancer Program, Helen Diller Family Comprehensive Cancer Center; UCSF Department of Pathology; and Cepheid.

Metastasis is a complex process that remains poorly understood at the molecular levels. We profiled single-cell transcriptomic, genomic, and epigenomic changes associated with cancer cell progression, chemotherapy resistance, and metastasis from a Stage IV breast cancer patient. Pretreatment- and posttreatment-specimens from the primary tumor and distant metastases were collected for single-cell RNA sequencing and subsequent cell clustering, copy number variation (CNV) estimation, transcriptomic factor estimation, and pseudotime analyses. CNV analysis revealed that a small population of pretreatment cancer cells resisted chemotherapy and expanded. New clones including Metastatic Precursor Cells (MPCs), emerged in the posttreatment primary tumors in CNV similar to metastatic cells. MPCs exhibited expression profiles indicative of epithelial-mesenchymal transition. Comparison of MPCs with metastatic cancer cells also revealed dynamic changes in transcription factors and calcitonin pathway gene expression. These findings demonstrate the utility of single-patient clinical sample analysis for understanding tumor drug resistance, regrowth, and metastasis.

Texture and radiomic analysis characterizes the tumor's phenotype and evaluates its microenvironment in quantitative terms. This study aims to investigate the role of textural and radiomic analysis parameters in predicting histopathological factors in breast cancer patients.

Two hundred and twelve primary breast cancer patients underwent 18 F-FDG PET/computed tomography for staging. The images were processed in a commercially available textural analysis software. ROI was drawn over the primary tumor with a 40% threshold and was processed further to derive textural and radiomic parameters. These parameters were then compared with histopathological factors of tumor. Receiver-operating characteristic analysis was performed with a P -value <0.05 for statistical significance. The significant parameters were subsequently utilized in various machine learning models to assess their predictive accuracy.

A retrospective study of 212 primary breast cancer patients was done. Among all the significant parameters, SUVmin, SUVmean, SUVstd, SUVmax, discretized HISTO_Entropy, and gray level co-occurrence matrix_Contrast were found to be significantly associated with ductal carcinoma type. Four parameters (SUVmin, SUVmean, SUVstd, and SUVmax) were significant in differentiating the luminal subtypes of the tumor. Five parameters (SUVmin, SUVmean, SUVstd, SUVmax, and SUV kurtosis) were significant in predicting the grade of the tumor. These parameters showcased robust capabilities in predicting multiple histopathological parameters when tested using machine learning algorithms.

Though textural analysis could not predict hormonal receptor status, lymphovascular invasion status, perineural invasion status, microcalcification status of tumor, and all the molecular subtypes of the tumor, it could predict the tumor's histologic type, triple-negative subtype, and score of the tumor noninvasively.

PET/CT using 16α-[18F]-fluoro-17β-estradiol (FES) noninvasively images tissues expressing estrogen receptors (ERs). FES has undergone extensive clinicopathologic validation for ER-positive breast cancer and in 2020 received FDA approval for clinical use as an adjunct to biopsy in patients with recurrent or metastatic ER-positive breast cancer. Clinical use of FES PET/CT is increasing but is not widespread in the United States. This AJR Expert Panel Narrative Review explores the present status and future directions of FES PET/CT, including image interpretation, existing and emerging uses, knowledge gaps, and current controversies. Specific controversies discussed include whether both FES PET/CT and FDG PET/CT are warranted in certain scenarios, whether further workup is required after negative FES PET/CT results, whether FES PET/CT findings should inform endocrine therapy selection, and whether immunohistochemistry should remain the stand-alone reference standard for determining ER status for all breast cancers. Consensus opinions from the panel include agreement with the appropriate clinical uses of FES PET/CT published by a multidisciplinary expert work group in 2023, anticipated expanded clinical use of FES PET/CT for staging ER-positive invasive lobular carcinomas and low-grade invasive ductal carcinomas pending ongoing clinical trial results, and the need for further research regarding the use of FES PET/CT for nonbreast malignancies expressing ER.

Triple-negative breast cancer (TNBC) accounts for disproportionately poor outcomes in breast cancer, driven by a subset of rapid-relapse TNBC (rrTNBC) with marked chemoresistance, rapid metastatic spread, and poor survival. This study aimed to develop and validate a nomogram based on clinicopathological characteristics to predict rapid relapse in TNBC patients treated with neoadjuvant chemotherapy (NAC) first.

The clinicopathological data of 504 TNBC patients treated with NAC first in Tianjin Medical University Cancer Hospital were analyzed retrospectively, with 109 rapid relapsed patients, and 395 non-rapid relapsed patients, respectively. Based on clinicopathologic characteristics, and follow-up data were analyzed. The independent predictors of clinicopathological characteristics were identified by logistic regression analysis and then used to build a nomogram. The concordance index (C-index), the area under the curve (AUC) of receiver operating characteristic (ROC), and calibration plots were used to evaluate the performance of the model.

Univariate and multivariate logistic regression analyses showed that age at diagnosis (age≥50 years, OR = 0.325,95% CI:0.137-0.771), Nodal staging (N3 staging, OR = 13.669,95% CI:3.693-50.592),sTIL expression levels (sTIL intermediate expression, OR = 0.272,95% CI:0.109-0.678; sTIL high expression, OR = 0.169,95% CI:0.048-0.594), and NAC response (ORR, OR = 0.059,95% CI:0.024-0.143) were independent predictors of rapid relapse in TNBC patients treated with NAC firstly. Among these independent predictors, age ≥ 50 years, sTIL intermediate expression, sTIL high expression, and ORR in NAC were independent protective factors for rapid relapse in TNBC NAC patients. N3 staging was an independent risk factor for rapid relapse in TNBC NAC patients. The ROC curve, calibration curve, and decision curve analysis were used to validate the model. The C-Index of the training sets and validation sets were 0.938 and 0.910, respectively. The Brier scores of the training sets and validation sets were 0.076 and 0.097, respectively.

This study developed and verified a nomogram for predicting rapid relapse in TNBC NAC patients, and the predictive model had high discrimination and accuracy.

Background Specific molecular characteristics of invasive breast cancer have been linked to an increased risk of early relapse. Similarly, ductal carcinoma in situ (DCIS) displays a comparable molecular profile, although their prevalence and implications are not yet fully understood. Aims and objectives The study design defined a multivariable statistical approach aimed at describing the interplay between the histopathological features of ductal carcinoma in situ (DCIS) and their molecular profile. The objective was to explore the correlations between the histopathological features of DCIS (tumor location, DCIS grade, DCIS type, and presence or absence of comedo necrosis) and various biomarkers like estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER2/neu), androgen receptor (AR), and epidermal growth factor receptor (EGFR), in addition to the Ki-67 labeling index. Methods In this retrospective study, we selected and analyzed 100 diagnosed cases of ductal carcinoma in situ (DCIS) to represent various subtypes, grades, and morphological characteristics. A detailed histopathological review and immunohistopathological staining for ER, PR, HER2/neu, AR, EGFR, and Ki-67 were performed on formalin-fixed paraffin-embedded (FFPE) tumor tissue blocks. Molecular subtyping was done based on the biomarker analysis into luminal A, luminal B, luminal HER2/neu, HER2/neu enriched, and triple-negative subtypes. Statistical analysis was done to examine the correlation between tumor location, histopathological features of ductal carcinoma in situ (DCIS), and the expression of the immunohistochemical markers and the molecular subtypes. Results The majority of cases exhibited positivity for estrogen receptor (ER) and progesterone receptor (PR). A strong association was observed between histopathological features (DCIS grade, type, and comedo necrosis) of DCIS and ER/PR status. Additionally, a significant correlation was found between ductal carcinoma in situ (DCIS) grade and HER2/neu status. However, no association was identified between histopathological features and AR or EGFR status. Contrary to expectations, triple-negative DCIS did not show the most aggressive behavior, whereas HER2/neu-positive tumors, particularly high-grade ones, exhibited more aggressive features. No low-grade cases of luminal HER2/neu and HER2/neu-enriched tumors were found. A higher Ki-67 labeling index was found in cases with grade 3 and solid and comedo architectural types of DCIS, while low-grade tumors had a lower Ki-67 labeling index. Conclusion These findings suggest that hormone pathways play a crucial role in ductal carcinoma in situ (DCIS) progression, but the molecular interactions are complex and extend beyond simple binary associations. The complex relationship between the histopathological features of ductal carcinoma in situ (DCIS) and its hormone receptor status warrants further investigation with a larger sample size to fully understand the underlying mechanisms. The results challenge the expectation that triple-negative DCIS is the most aggressive subtype, highlighting the need for further research into the prognostic significance of different DCIS subtypes.

Current national or regional guidelines for the pathology reporting on invasive breast cancer differ in certain aspects, resulting in divergent reporting practice and a lack of comparability of data. Here we report on a new international dataset for the pathology reporting of resection specimens with invasive cancer of the breast. The dataset was produced under the auspices of the International Collaboration on Cancer Reporting (ICCR), a global alliance of major (inter-)national pathology and cancer organizations.

The established ICCR process for dataset development was followed. An international expert panel consisting of breast pathologists, a surgeon, and an oncologist prepared a draft set of core and noncore data items based on a critical review and discussion of current evidence. Commentary was provided for each data item to explain the rationale for selecting it as a core or noncore element, its clinical relevance, and to highlight potential areas of disagreement or lack of evidence, in which case a consensus position was formulated. Following international public consultation, the document was finalized and ratified, and the dataset, which includes a synoptic reporting guide, was published on the ICCR website.

This first international dataset for invasive cancer of the breast is intended to promote high-quality, standardized pathology reporting. Its widespread adoption will improve consistency of reporting, facilitate multidisciplinary communication, and enhance comparability of data, all of which will help to improve the management of invasive breast cancer patients.

The events that control breast cancer progression and metastasis are complex and intertwined. Hypoxia plays a key role both in oncogenic transformation and in fueling the metastatic potential of breast cancer cells. Here we review the impact of hypoxia on epigenetic regulation of breast cancer, by interfering with multiple aspects of the tumour microenvironment. The co-dependent relationship between oxygen depletion and metabolic shift to aerobic glycolysis impacts on a range of enzymes and metabolites available in the cell, promoting posttranslational modifications of histones and chromatin, and changing the gene expression landscape to facilitate tumour development. Hormone signalling, particularly through ERα, is also tightly regulated by hypoxic exposure, with HIF-1α expression being a prognostic marker for therapeutic resistance in ER+ breast cancers. This highlights the strong need to understand the hypoxia-endocrine signalling axis and exploit it as a therapeutic target. Furthermore, hypoxia has been shown to enhance metastasis in TNBC cells, as well as promoting resistance to taxanes, radiotherapy and even immunotherapy through microRNA regulation and changes in histone packaging. Finally, several other mediators of the hypoxic response are discussed. We highlight a link between ionic dysregulation and hypoxia signalling, indicating a potential connection between HIF-1α and tumoural Na+ accumulation which would be worth further exploration; we present the role of Ca2+ in mediating hypoxic adaptation via chromatin remodelling, transcription factor recruitment and changes in signalling pathways; and we briefly summarise some of the findings regarding vesicle secretion and paracrine induced epigenetic reprogramming upon hypoxic exposure in breast cancer. By summarising these observations, this article highlights the heterogeneity of breast cancers, presenting a series of pathways with potential for therapeutic applications.

Oncogene activation through DNA amplification or overexpression is a crucial driver of cancer initiation and progression. The FOXK2 gene, located on chromosome 17q25, encodes a transcription factor with a forkhead DNA-binding domain. Analysis of genomic datasets reveals that FOXK2 is frequently amplified and overexpressed in breast cancer, correlating with poor patient survival. Knockdown of FOXK2 significantly inhibited breast cancer cell proliferation, migration, anchorage-independent growth, and delayed tumor growth in a xenograft mouse model. Additionally, inhibiting FOXK2 sensitized breast cancer cells to chemotherapy. Co-overexpression of FOXK2 and mutant PI3KCA transformed non-tumorigenic MCF-10A cells, suggesting a role for FOXK2 in PI3KCA-driven tumorigenesis. CCNE2, PDK1, and ESR1 were identified as transcriptional targets of FOXK2 in MCF-7 cells. Small-molecule inhibitors of CCNE2/CDK2 (dinaciclib) and PDK1 (dichloroacetate) exhibited synergistic anti-tumor effects with PI3KCA inhibitor (alpelisib) in vitro. Inhibition of FOXK2 by dinaciclib synergistically enhanced the anti-tumor effects of alpelisib in a xenograft mouse model. Collectively, these findings highlight the oncogenic function of FOXK2 and suggest that FOXK2 and its downstream genes represent potential therapeutic targets in breast cancer.

Solid tumours have abnormally high intracellular [Na+]. The activity of various Na+ channels may underlie this Na+ accumulation. Voltage-gated Na+ channels (VGSCs) have been shown to be functionally active in cancer cell lines, where they promote invasion. However, the mechanisms involved, and clinical relevance, are incompletely understood. Here, we show that protein expression of the Nav1.5 VGSC subtype strongly correlates with increased metastasis and shortened cancer-specific survival in breast cancer patients. In addition, VGSCs are functionally active in patient-derived breast tumour cells, cell lines, and cancer-associated fibroblasts. Knockdown of Nav1.5 in a mouse model of breast cancer suppresses expression of invasion-regulating genes. Nav1.5 activity increases ATP demand and glycolysis in breast cancer cells, likely by upregulating activity of the Na+/K+ ATPase, thus promoting H+ production and extracellular acidification. The pH of murine xenograft tumours is lower at the periphery than in the core, in regions of higher proliferation and lower apoptosis. In turn, acidic extracellular pH elevates persistent Na+ influx through Nav1.5 into breast cancer cells. Together, these findings show positive feedback between extracellular acidification and the movement of Na+ into cancer cells which can facilitate invasion. These results highlight the clinical significance of Nav1.5 activity as a potentiator of breast cancer metastasis and provide further evidence supporting the use of VGSC inhibitors in cancer treatment.

Endocrine treatment, particularly tamoxifen, has shown significant improvement in the prognosis of patients with estrogen receptor-positive (ER-positive) breast cancer. However, the clinical utility of this treatment is often hindered by the development of endocrine resistance. Therefore, a comprehensive understanding of the underlying mechanisms driving ER-positive breast cancer carcinogenesis and endocrine resistance is crucial to overcome this clinical challenge. In this study, we investigated the expression of MICAL-L2 in ER-positive breast cancer and its impact on patient prognosis. We observed a significant upregulation of MICAL-L2 expression in ER-positive breast cancer, which correlated with a poorer prognosis in these patients. Furthermore, we found that estrogen-ERβ signaling promoted the expression of MICAL-L2. Functionally, our study demonstrated that MICAL-L2 not only played an oncogenic role in ER-positive breast cancer tumorigenesis but also influenced the sensitivity of ER-positive breast cancer cells to tamoxifen. Mechanistically, as an estrogen-responsive gene, MICAL-L2 facilitated the activation of the AKT/mTOR signaling pathway in ER-positive breast cancer cells. Collectively, our findings suggest that MICAL-L2 could serve as a potential prognostic marker for ER-positive breast cancer and represent a promising molecular target for improving endocrine treatment and developing therapeutic approaches for this subtype of breast cancer.

A 61-year-old woman with BRCA2 pathogenic variant had been treated for 20 years and showed dynamic changes in the genomic profile of her metachronous bilateral breast cancer and metastases. She underwent right breast conservation surgery at age 42-Genome 1, lung metastasis and left axillary lymph node metastasis at age 51, partial excision under local anesthesia for left breast cancer at age 53-Genome 2, left axillary lymph node dissection was added 6 month later-Genome 3. Then, olaparib was administered, and subsequently, left mastectomy was performed for the recurrence of left breast cancer at age 59-Genome 4. Genomic profile of the tumor was analyzed at four points (Genome 1-3 were analyzed by in house breast cancer panel, and Genome 4 was analyzed by Foundation One CDx). Two interesting findings emerged from these analyses. First, the genomic profile revealed that the left axillary lymph node metastasis, considered histologically from right breast cancer, was a metastasis from the left breast cancer. The second finding is that as the disease progressed, mutation profile became more diverse. The profile of the left breast cancer removed after olaparib and other treatments showed reversion mutation of BRCA2 and was diagnosed as tumor mutation burden high. Subsequent response to pembrolizumab was favorable.

It is generally assumed that all estrogen-receptor-positive (ER+) breast cancers proliferate in response to estrogen and, therefore, examples of the estrogen-induced regression of ER+ cancers are paradoxical. This review re-examines the estrogen regression paradox for the Luminal A subtype of ER+ breast cancers. The proliferative response to estrogen is shown to depend on the level of ER. Mechanistically, a window of opportunity study of pre-operative estradiol suggested that with higher levels of ER, estradiol could activate the DREAM-MMB (Dimerization partner, Retinoblastoma-like proteins, E2F4, and MuvB-MYB-MuvB) pathway to decrease proliferation. The response of breast epithelium and the incidence of breast cancers during hormonal variations that occur during the menstrual cycle and at the menopausal transition, respectively, suggest that a single hormone, either estrogen, progesterone or androgen, could activate the DREAM pathway, leading to reversible cell cycle arrest. Conversely, the presence of two hormones could switch the DREAM-MMB complex to a pro-proliferative pathway. Using publicly available data, we examine the gene expression changes after aromatase inhibitors and ICI 182,780 to provide support for the hypothesis. This review suggests that it might be possible to integrate all current hormonal therapies for Luminal A tumors within a single theoretical schema.

It remains unclear whether patients with HER2-negative, low-estrogen receptor (ER-low)-positive early breast cancer (BC) benefit from Oncotype DX® (ODX) testing.

We conducted a retrospective review of cases referred for ODX testing over a seven-year period from a breast biomarker testing referral center (n = 854). For each case, we recorded the ODX Recurrence Score (RS) along with percentage of ER nuclear positivity and staining intensity on immunohistochemistry. Our criteria for ER-low was defined as ≤10% cells with nuclear positivity and/or weak intensity of staining. Slides from all ER-low cases were reviewed and the reported ODX ER gene scores were recorded. We randomly selected a comparator group of 56 patients with ER > 10% positivity and non-weak staining intensity (ER-high).

We identified 27 cases (3.2%) that met our criteria for ER-low. Of these, 92.6% had a high RS (>25), and 7.4% had a RS of 25. All cases with ≤10% ER nuclear positivity had a high RS. Most ER-low cases (85.2%) had ODX quantitative ER gene scores in the negative range, whereas all (100%) ER-high cases had positive ER gene scores.

ODX does not appear to add significant additional information to inform treatment decisions for most patients with ER-low BC. Incorporating weak ER staining intensity in addition to low percentage of nuclear positivity identifies about twice as many ER-low patients, although with reduced specificity for high RS. Our study supports the contention that most ER-low early BC should be regarded similarly to ER-negative BC.

Spatial findings have shaped on our understanding of breast cancer. In this review, we discuss how spatial methods, including spatial transcriptomics and proteomics and the resultant understanding of spatial relationships, have contributed to concepts regarding cancer progression and treatment. In addition to discussing traditional approaches, we examine how emerging multiplex imaging technologies have contributed to the field and how they might influence future research.

Steroid receptors regulate gene expression for many important physiologic functions and pathologic processes. Receptors for estrogen, progesterone, and androgen have been extensively studied in breast cancer, and their expression provides prognostic information as well as targets for therapy. Noninvasive imaging utilizing positron emission tomography and radiolabeled ligands targeting these receptors can provide valuable insight into predicting treatment efficacy, staging whole-body disease burden, and identifying heterogeneity in receptor expression across different metastatic sites. This review provides an overview of steroid receptor imaging with a focus on breast cancer and radioligands for estrogen, progesterone, and androgen receptors.

Ulipristal (UPA), a selective progesterone receptor modulator, has both agonistic and antagonistic effects on progesterone receptors. UPA suppresses ovulation by inhibiting the luteinizing hormone (LH) surge from the pituitary gland; however, the direct effect of UPA on ovarian tissue remains poorly studied. In the present study, we examined the effects of UPA on the ovaries of rats. Rats were treated for 28 days with UPA, and the effects of UPA on ovarian tissue were examined histologically and the expression of antioxidant genes and cell death markers were also investigated. UPA treatment increased the number of primordial follicles at each treatment group, primordial follicles increased at all dose levels, but the size/magnitude of the effect decreased with the increasing dose. The number of primary and antral follicles tended to increase with increasing UPA levels. Furthermore, the decrease in primary follicle number could be attributed to the exhaustion of follicles, but the examination of proliferation markers, oxidative stress markers, and cell death markers revealed no remarkable toxic effects on ovarian tissues. These results suggest that UPA treatment promotes follicle development at each stage but inhibits ovulation by suppressing the LH surge, resulting in an increase in atretic follicles or unruptured luteinized cysts. These results suggest that UPA may not have both toxic effects on the ovary and a direct local effect on ovarian follicles, but we should be careful about the effects of prolonged UPA treatment in patients with uterine fibroids on their future fecundity.