ARID1A, a subunit of the SWI/SNF chromatin-remodeling complex, functions as a tumor suppressor in various cancer types. Owing to its high frequency of inactivating mutations, ARID1A has emerged as a promising target for the development of anticancer drugs. In this study, we report that ARID1A-deficient colorectal cancer (CRC) cells induce synthetic lethality when treated with inhibitors of c-MET receptor tyrosine kinase. c-MET specific inhibitor PHA-665752 as well as two other FDA-approved drugs, crizotinib and cabozantinib, selectively inhibited the growth of ARID1A-deficient CRC cells in vitro and in xenograft tumor models. Mechanistically, we identified a tripartite functional association among ARID1A, c-MET, and NRF2, where ARID1A and c-MET pathways converge on the NRF2 transcription factor, which regulates the transcription of GPX4, a key regulator of ferroptosis. ARID1A inactivation reduces c-MET expression, decreasing NRF2 nuclear localization and its binding to the GPX4 promoter, resulting in reduced GPX4 transcription. This creates a cellular dependency on the residual c-MET for minimal GPX4 expression to survive the ferroptotic cell death. Additionally, we demonstrate that ARID1A loss leads to increased intracellular labile iron accumulation by downregulating the iron-exporting protein SLC40A1, thereby increasing cellular susceptibility to ferroptosis. Inhibition of c-MET in ARID1A-deficient CRC cells diminishes GPX4 expression, resulting in elevated lipid peroxidation and glutathione depletion, ultimately inducing ferroptosis. This study reveals a novel synthetic lethal relationship between ARID1A and c-MET signaling in promoting ferroptosis and proposes c-MET inhibitors as a potential therapeutic strategy for ARID1A-deficient CRC.

The SWI/SNF complex was first identified in yeast and named after studies of mutants critical for the mating-type switch (SWI) and sucrose non-fermenting (SNF) pathways.The SWI/SNF complex plays a pivotal role in regulating gene expression by altering chromatin structure to promote or suppress the expression of specific genes, maintain stem cell pluripotency, and participate in various biological processes. Mutations in the SWI/SNF complex are highly prevalent in various human cancers, significantly impacting tumor suppressive or oncogenic functions and influencing tumor initiation and progression. This review focuses on the mechanisms by which ARID1A/ARID1B, PBRM1, SMARCB1, and SMARCA2/SMARCA4 contribute to cancer, the immunoregulatory roles of the SWI/SNF complex, its involvement in DNA repair pathways, synthetic lethality, and applications in precision oncology.

Ovarian clear-cell carcinoma (OCCC), particularly advanced or recurrent settings, is generally resistant to platinum-based chemotherapy, warranting novel therapeutic strategies. Mutations in the PI3K/AKT/mTOR pathway are frequently reported in OCCC. Therefore, we hypothesized that the PI3K/mTOR dual inhibitor, GSK458, and arsenic trioxide (As2O3) may exert synergistic antitumor effects on OCCC. We investigated the effects of GSK458, As2O3, and the combination of GSK458 and As2O3 on cell viability, colony formation, and apoptosis in seven OCCC cells. Mechanistically, transcriptomic differences were assessed among the groups. Additionally, their antitumor effects were evaluated on the three-dimensional cultures of OCCC patient-derived xenografts as well as in vivo. Low-dose combination of GSK458 and As2O3 exerted synergistic antitumor effects in vitro. Viability of the three-dimensional OCCC patient-derived xenograft cultures treated with the combination of GSK458 and As2O3 decreased to 23.8% of that of the control. RNA sequencing revealed that the mechanism was associated with cell cycle and DNA damage repair. The combination of GSK458 and As2O3 synergistically inhibited the PI3K/AKT/mTOR pathway and angiogenesis and increased apoptosis. Compared with any monotherapy, the combination treatment significantly suppressed tumor growth in vivo, thereby enhancing survival. Overall, our findings highlight the potential of the novel combination of GSK458 and As2O3 for OCCC treatment.

Prostate cancer (PC) is the commonest male visceral cancer, and second leading cause of cancer mortality in men in the Western world.

Using a forward-mutagenesis Sleeping Beauty (SB) transposon-based screen in a Probasin Cre-Recombinase (Pb-Cre) Pten-deficient mouse model of PC, we identified Arid1a loss as a driver in the development of metastatic disease.

The insertion of transposon in the Arid1a gene resulted in a 60% reduction of Arid1a expression, and reduced tumour free survival (SB:Ptenfl/fl Arid1aINT median 226 days vs SB:Ptenfl/fl Arid1aWT 293 days, p = 0.02),with elevated rates of metastasis (SB:Ptenfl/fl Arid1aINT 75% lung metastasis rate vs 17% SB:Ptenfl/fl Arid1aWT, p < 0.001). We further generated a Pb-Cre Pten- and Arid1a-deficient mouse model, in which loss of Arid1a demonstrated a profound acceleration in tumorigenesis in Ptenfl/fl mice compared to Pten loss alone (Pb-Cre Ptenfl/flArid1a+/+ median survival of 267 days vs Pb-Cre Ptenfl/fl Arid1afl/fl 103 days, p < 0.0001).

Our data revealed homozygous Arid1a loss is required to dramatically accelerate prostate tumourigenesis. Analysis of RNA and ChIP -Sequencing data suggests Arid1a loss enhanced the function of AP-1 subunit cFos. In clinical PC cohort, ARID1A and cFos levels stratified an aggressive subset of PC with a poor survival outcome with a median of only 30 months.

Ovarian cancer is the third most common gynecological cancer worldwide. Due to the high recurrence rate of advanced-stage ovarian cancer, often resulting from drug-resistant and refractory disease, various treatment strategies are under investigation. Genome editing of therapeutic target genes holds promise in enhancing cancer treatment efficacy by elucidating gene functions and mechanisms involved in cancer progression. The CRISPR/Cas9 system, in particular, shows great potential in ovarian cancer gene therapy and drug development. Targeting therapeutic genes such as BRCA1/2, P53, Snai1 etc, could improve the therapeutic strategy in ovarian cancer. CRISPR/Cas9 is a powerful gene-editing tool that there are many on-going clinical trials to treat various diseases including cancer. Nano-based delivery systems for CRISPR/Cas9 offer further therapeutic benefits, leveraging the unique properties of nanoparticles to improve delivery efficiency. Nano-based delivery systems could enhance the stability of CRISPR/Cas9 delivery formats (such as plasmid, mRNA, etc) and improve the delivery precision of delivery to target tumors. Additionally, combining CRISPR/Cas9 with targeted drug treatments, especially those aimed at genes associated with drug resistance, may significantly improve therapeutic outcomes in ovarian cancer. In this review, we discuss therapeutic target genes and their mechanisms in ovarian cancer, advances in nano-based CRISPR/Cas9 delivery, and the therapeutic potential of combining CRISPR/Cas9 with drug treatments for ovarian cancer.

Ovarian clear cell carcinomas (OCCCs) are a rare histological subtype of epithelial ovarian cancer characterized by resistance to platinum-based therapy. CDK8/19, a component of the regulatory CDK module associated with Mediator complex, has been implicated in transcriptional reprogramming and drug resistance in various solid tumors. Our study aimed to investigate the therapeutic potential of CDK8/19 kinase inhibition using selective inhibitors SNX631 and SNX631-6 in OCCC treatment, both as monotherapy and in combination with standard chemotherapeutics.

CDK8 and Ki67 levels were evaluated via immunohistochemistry in benign, primary, and metastatic ovarian cancer tissues. The efficacy of SNX631 alone and in combination with cisplatin or paclitaxel was assessed in OCCC cell lines (ES-2, TOV-21-G, RMG-1). In vivo evaluation utilized xenograft models with subcutaneous and intraperitoneal delivery of the OCCC ES2 cells and oral delivery of SNX631-6, with the monitoring of tumor growth, metastatic spread, and survival.

CDK8 protein levels were elevated in OC tissues, particularly in OCCC primary and metastatic lesions compared to benign tissue. While CDK8/19 inhibition showed limited effects on in vitro cell proliferation, SNX631-6 demonstrated significant antitumor and anti-metastatic activity in vivo. Notably, SNX631-6 enhanced the efficacy of cisplatin, substantially inhibiting tumor growth and extending overall survival.

Therapeutically achievable doses of CDK8/19 inhibitors may provide clinical benefit for OCCC patients by inhibiting tumor growth and reversing platinum resistance, potentially addressing a critical treatment challenge in this rare ovarian cancer subtype.

Clear cell ovarian and endometrial carcinomas are rare and aggressive gynecologic malignancies that present unique challenges owing to their underrepresentation in clinical trials and limited prospective data. In this report, we aimed to explore 3 major controversies in the management of clear cell ovarian and endometrial carcinomas, highlighting areas that require further investigation. First, we addressed the unique phenotypic characteristics of clear cell ovarian carcinoma and clear cell endometrial carcinoma and whether they should be considered a unified disease entity or a distinct disease. Recent trials grouped these carcinomas, potentially expanding their therapeutic options. However, emerging molecular data underscores the significant differences between clear cell ovarian carcinoma and clear cell endometrial carcinoma, raising questions regarding this combined approach. This distinction is critical in guiding tailored treatment strategies. Second, we examined the management of localized diseases. Although early-stage diagnoses are common in clear cell carcinomas, optimal surgical and adjuvant treatment strategies remain uncertain. Current practice often relies on data from broader studies with limited inclusion of clear cell histology. This review underscores the need for more specific evidence to refine treatment protocols and balance efficacy with the minimization of treatment-related morbidity. Third, we explored novel therapeutic strategies for the treatment of recurrent diseases. Advances in the understanding of the biology of clear cell carcinomas have identified potential targets in the immune microenvironment, cellular processes, and metabolism. Ongoing clinical trials are investigating these approaches, which hold promise in transforming the treatment landscape and outcomes. In conclusion, this review emphasizes the necessity for international collaboration and the inclusion of diverse patient populations to address the challenges posed by cell carcinomas. By focusing on these controversies, we aim to stimulate further research and support more evidence-based personalized approaches for the management of these rare but challenging cancers.

Ovarian carcinosarcoma (OCS) is a rare and aggressive tumor, and the development of its sarcomatous component is believed to be due to epithelial-mesenchymal transition (EMT). The SWIch/sucrose nonfermentable chromatin remodeling factor (CRF) is closely related to EMT; however, the relationship between CRF and EMT in OCS remains unclear. In this study, we analyzed the protein expression of CRFs, including ARID1A and SMARCA4, and their downstream mRNA expression in 28 OCS cases, two fallopian tube CS cases, and one peritoneal CS case. ARID1A and SMARCA4 exhibited a histological type-specific loss of protein expression in 5 of 11 (45%) endometrioid cases and all 5 serous/homologous OCS cases, respectively. The mRNA analysis suggested that sarcomatogenesis is induced by the transforming growth factor-β and Hippo signaling pathways, both of which regulate YAP1. Immunostaining for YAP1 suggested YAP1-associated sarcomatogenesis in the CRF-retained group, whereas YAP1-unassociated sarcomatogenesis was suggested in the CRF-reduced group. High-grade serous carcinoma cell line experiments showed that the transcriptome of the SMARCA4-knockdown group showed lower expression of the epithelial gene CDH1 and higher expression of mesenchymal genes such as VIM, ZEB1, and SNAI1 than the control group. Moreover, cell adhesion disappeared and cell morphology changed to a spindle shape, indicating sarcomatogenesis. In conclusion, this study reveals a mechanism for sarcoma development in OCS and provides novel therapeutic possibilities.

Identification of ARID1A/ATR synthetic lethality led to ATR inhibitor phase II trials in ovarian clear cell carcinoma (OCCC), a cancer of unmet need. Using multiple CRISPR-Cas9 mutagenesis and interference screens, we show that inactivation of protein phosphatase 2A (PP2A) subunits, including PPP2R1A, enhance ATRi sensitivity in ARID1A mutant OCCC. Analysis of a new OCCC cohort indicates that 52% possess oncogenic PPP2R1A p.R183 mutations and of these, one half possessed both ARID1A as well as PPP2R1A mutations. Using CRISPR-prime editing to generate new isogenic models of PPP2R1A mutant OCCC, we found that PPP2R1A p.R183W and p.R183P mutations cause ATRi-induced S phase stress, premature mitotic entry, genomic instability and ATRi sensitivity in OCCC tumour cells. p.R183 mutation also enhanced both in vitro and in vivo ATRi sensitivity in preclinical models of ARID1A mutant OCCC. These results argue for the assessment of PPP2R1A mutations as a biomarker of ATRi sensitivity.

The SWI/SNF chromatin-remodeling complex that comprises multiple subunits orchestrates diverse cellular processes, including gene expression, DNA repair, and DNA replication, by sliding and releasing nucleosomes. AT-interacting domain-rich protein 1A (ARID1A) and ARID1B (ARID1A/B), a pivotal subunit, have significant relevance in cancer management because they are frequently mutated in a broad range of cancer types. To delineate the protein network involving ARID1A/B, we investigated the interactions of this with other proteins under physiological conditions. The ARID domain of ARID1A/B interacts with proteins involved in transcription and DNA/RNA metabolism. Several proteins are responsible for genome integrity maintenance, including DNA-dependent protein kinase catalytic subunit (DNA-PKcs), bound to the armadillo (ARM) domain of ARID1A/B. Introducing a knock-in mutation at the binding amino acid of DNA-PKcs in HCT116 cells reduced the autophosphorylation of DNA-PKcs and the recruitment of LIG4 in response to ionizing radiation. Our findings suggest that within the SWI/SNF complex, ARID1A couples DNA double-strand break repair processes with chromatin remodeling via the ARM domains to directly engage with DNA-PKcs to maintain genome stability.

The molecular mechanisms through which endometriosis-related ovarian neoplasms (ERONs) develop from benign endometrioma remain unclear. It is especially a long-standing mystery why ovarian endometrioma has the potential to develop into two representative histological subtypes: endometrioid ovarian carcinoma or clear cell ovarian carcinoma. This study aimed to investigate the molecular carcinogenesis of ERONs using newly developed in vitro and in vivo carcinogenesis models. Epithelial cells were isolated and purified from surgically removed benign endometrioma samples, followed by immortalization by overexpressing cyclinD1/CDK4 in combination with the human TERT gene. Immortalized cells were subjected to various molecular manipulations by combining knockout or overexpression of several candidate drivers, including ARID1A, KRAS, PIK3CA, AKT, and MYC, based on previous comprehensive genome-wide studies of ERONs. These cells were then inoculated into immunocompromised mice and evaluated for malignant transformation. Inoculated cells harboring a combination of three genetic alterations successfully developed tumors with malignant features in mice, whereas those with two genetic manipulations failed to do so. Especially, ARID1A gene knockout, combined with overexpressing the KRAS oncogenic mutant allele (or overexpressing AKT) and c-Myc overexpression led to efficient tumor formation. Of note, these three combinations of genetic alterations produced tumors that histologically represented typical clear cell carcinoma in SCID mice, while the same combination led to tumors with endometrioid histology in nude mice. A combination of ARID1A mutation, KRAS mutation or AKT activation, and c-Myc overexpression were confirmed to be the main candidate drivers for the development of ERONs, as suggested by comprehensive genetic analyses of ERONs. A tumor immune microenvironment involving B-cell signaling may contribute to the diverse histological phenotypes. The present model may help to clarify the molecular mechanisms of ERON carcinogenesis and understand their histological diversity and novel molecular targets.

Colorectal cancer (CRC) has increased at an alarming rate amongst younger (< 50 years) individuals. Such early-onset colorectal cancer (EOCRC) has been particularly notable within the Hispanic/Latino population. Yet, this population has not been sufficiently profiled in terms of two critical elements of CRC -- the MYC proto-oncogene and WNT signaling pathway. Here, we performed a comprehensive multi-omics analysis on 30 early-onset and 37 late-onset CRC (≥ 50 years) samples from Hispanic/Latino patients. Our analysis included DNA exome sequencing for somatic mutations, somatic copy number alterations, and global and local genetic similarity. Using RNA sequencing, we also assessed differential gene expression, cellular pathways, and gene fusions. We then compared our findings from early-onset Hispanic/Latino patient samples with publicly available data from Non-Hispanic White cohorts. Across all early-onset patients, which had a median 1000 Genomes Project Peruvian-in-Lima-like (1KG-PEL-like) genetic similarity proportion of 60%, we identified 41 WNT pathway genes with significant mutations. Six important examples were APC, TCF7L2, DKK1, DKK2, FZD10, and LRP5. Notably, patients with mutations in DKK1 and DKK2 had the highest 1KG-PEL-like proportion (79%). When we compared the Hispanic/Latino cohort to the Non-Hispanic White cohorts, four of these key genes -- DKK1, DKK2, FZD10, and LRP5 -- were significant in both risk association analyses and differential gene expression. Interestingly, early-onset tumors (vs. late-onset) exhibited distinct somatic copy number alterations and gene expression profiles; the differences included MYC and drug-targetable WNT pathway genes. We also identified a novel WNT gene fusion, RSPO3, in early-onset tumors; it was associated with enhanced WNT signaling. This integrative analysis underscores the distinct molecular features of EOCRC cancer in the Hispanic/Latino population; reveals potential avenues for tailored precision medicine therapies; and emphasizes the importance of multi-omics approaches in studying colorectal carcinogenesis. We expect this data to help contribute towards reducing cancer health disparities.

This study offers multi-omics profiling analysis of early-onset colorectal cancer (EOCRC) in an underserved community, explores the implications of MYC gene and WNT pathway alterations, and provides critical insights into cancer health disparities.

Interest in understanding the high chemoresistance and poor prognosis of advanced ovarian clear cell carcinoma (OCCC) is rising. Patient-derived xenografts (PDX) are widely used in vivo models because of their supposedly accurate morphologic and (epi)genetic representation of patient tumors. Here, we established five subcutaneous OCCC PDXs. The PDX.F1 engraftment success rate was over 30% with similar latency time and growth speed of PDX.F2. ARID1A, PTEN, ATM, BRCA1 and PIK3CA mutations were found in matched tumors and PDXs. ARID1A protein loss was further verified by immunohistochemical staining. Cyclophilin A staining depicted the replacement of human stroma by mouse stroma in PDX.F2, while PAS/PAS-D staining confirmed cellular glycogen accumulation in OCCC tumors and PDXs. SNP array and Infinium MethylationEPIC BeadChip array data analysis demonstrated the copy number alterations and DNA methylation signatures of genome-wide and tumor-driver genes in PDXs generally resembled their patients' tumors. Promoter CpG islands of a small number of genes, enriched in PRC2/histone methylation related gene-sets, gained methylation (△β-value > 0.4) in PDXs vs patient tumors. In conclusion, the high phenotypic and molecular similarity allows the established PDXs to serve as potential preclinical models for future translational research of OCCC.

Patients with high-grade serous carcinoma (HGSC) are commonly diagnosed at late disease stages and after primary tumors have disseminated in the peritoneum. The overexpression of tight junction proteins has been associated with poor prognosis in this setting, potentially reflecting the tumor´s adaptive changes in the disease cascade.

By performing immunohistochemistry in a large single-center cohort of a total of 705 HGSC, we test the hypothesis that the protein expression of PReferentially expressed Antigen of MElanoma (PRAME) contains prognostic, predictive or clinically translatable information. We further examine its co-expression with tight junction proteins.

We confirmed the nuclear expression of PRAME in 442 (63 %) of specimens with comparable expression levels in peritoneal and pleural effusions (p = 0.72), and in effusions versus surgical specimens (p = 0.339). In effusions, any degree of expression of PRAME was significantly associated with suboptimal debulking surgery during primary treatment (p = 0.034). In surgical specimens, higher expression of PRAME was significantly linked to more advanced FIGO stage (p = 0.021). PRAME expression was not associated with other clinico-pathologic factors as age, CA125 levels, chemoresistance or survival, but correlated with PRAME mRNA levels. Significant correlation was found between expression levels of PRAME and the tight junction protein Occludin (p = 0.002).

Taken together, our study confirms PRAME to be expressed in the majority of HGSC effusions and surgical samples. The association of high levels of PRAME expression with incomplete surgical resection status and advanced stage disease may suggest PRAME expression as adaptative mechanism during disease dissemination. This finding warrants confirmation in independent series.

Is there an association between the somatic loss of PTEN (phosphatase and tensin homolog) and ARID1A (AT-rich interaction domain 1A) and endometriosis disease severity and worse clinical outcomes?

Somatic PTEN loss in endometriosis epithelium was associated with greater disease burden and subsequent surgical complexity.

Somatic cancer-driver mutations including those involving the PTEN and ARID1A genes exist in endometriosis without cancer; however, their clinical impact remains unclear.

This prospective longitudinal study involved endometriosis tissue and clinical data from 126 participants who underwent surgery at a tertiary center for endometriosis (2013-2017), with a follow-up period of 5-9 years.

PTEN and ARID1A loss was assessed using established immunohistochemistry (IHC) methods as proxies for somatic loss by two independent raters. PTEN and ARID1A status for each participant was defined as loss (loss in at least one sample for a participant) or retained (no loss in all samples for a participant). Primary analyses examined associations between PTEN and ARID1A loss and disease burden based on anatomic subtype (superficial peritoneal endometriosis (SUP), deep endometriosis (DE), ovarian endometrioma (OMA)) and rASRM stage (I-IV). Secondary analyses explored associations of PTEN and ARID1A loss with demographics, surgical difficulty, and pain scores (baseline and follow-up). Additionally, using previously published data on KRAS codon 12 mutations for this cohort, we investigated associations between variables in the primary and secondary analyses and acquiring two or more somatic events (PTEN loss, ARID1A loss, or KRAS mutation) in this cohort. The risk of reoperation over the 5-9 years was also examined.

PTEN loss (68.3%; 86 participants) exceeded ARID1A loss (24.6%; 31 participants). Inter-rater reliability was substantial for PTEN (k = 0.69; 95% CI: 0.62-0.77) and ARID1A (k = 0.64; 95% CI: 0.51-0.77). PTEN loss was significantly associated with more severe anatomic subtypes (P < 0.001; participants with SUP only = 46.4%; participants with DE only or OMA only = 72.7%; participants with mixed subtypes = 85.1%), and higher stages (P = 0.024; Stage I = 47.8%; Stage II = 73.7%; Stage III = 80.8%; Stage IV = 81.0%). Results were similar for ARID1A loss, albeit with smaller sample size limiting power. PTEN loss was further associated with non-White ethnicities (P = 0.017) and greater surgical difficulty (more frequent need for ureterolysis) (P = 0.02). There were no differences in pain scores (baseline or follow-up) based on PTEN or ARID1A status. Reoperation was uncommon (13.5% of the cohort), and patterns in reoperation rates based on the presence of somatic alterations did not reach statistical significance.

Sequencing was not performed to determine the type of PTEN and ARID1A somatic mutations resulting in loss of expression.

These results demonstrate a link between PTEN somatic loss and greater endometriosis disease burden. These findings underscore the potential relevance of PTEN loss and other somatic driver mutations in a future molecular classification of endometriosis.

This study was funded by Canadian Institutes of Health Research (CIHR) project grant (MOP-142273 and PJT-156084). P.J.Y. was supported by a Health Professional Investigator award from Michael Smith Health Research BC, Canada, and a Canada Research Chair (Tier 2) in Endometriosis and Pelvic Pain. M.S.A. was supported by a Michael Smith Health Research BC Scholar award, and CIHR project grants (369990, 462997, and 456767). The sponsors did not play any role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. C.A. declares receiving payment from Pfizer for a symposium; being on advisory boards for AbbVie and Pfizer; being President and past President of the Canadian Society for the Advancement of Gynecologic Excellence (CanSAGE), co-lead of EndoAct Canada, and a board member of IPPS. M.A.B. has received consulting fees from AbbVie and Pfizer and grants from Ferring outside the scope of this work. D.G.H. is the founder of Canxeia Health but has no current affiliation. M.K. has received consulting fees from Helix Biopharma outside the scope of this work. M.S.A. received reimbursement of travel and registration fees to attend and present at the 2023 and 2024 annual meetings for the Society for Reproductive Investigation (SRI). P.J.Y. declares receiving: payment for a lecture from the International Society for the Study of Women's Sexual Health (ISSWSH); honoraria from the CIHR; support to attend meetings from CanSAGE, ISSWSH, the International Pelvic Pain Society, the World Endometriosis Society (WES), the Society for the Study of Reproduction, and the Vulvodynia Summit; and discounted devices from Ohnut Wearable for a clinical trial. P.J.Y. is a data safety monitoring board member of a clinical trial funded by CIHR; and a strategic advisory board member for the Women's Health Research Institute. P.J.Y. served as a board of directors member for CanSAGE and ISSWSH; was a junior board of directors member for WES; is a current board of directors member for WES; and was a committee chair for the Society of Obstetricians and Gynaecologists of Canada. A subset of these results was presented by the first author at the 71st Society for Reproductive Investigation Annual Scientific Meeting on 15 March 2024. Other authors have nothing to declare.

N/A.

Ovarian clear cell carcinoma is a highly malignant gynecological tumor characterized by a high rate of chemotherapy resistance and poor prognosis. The PI3K/AKT/mTOR pathway is well-known to be closely related to the progression of various malignancies, and recent studies have indicated that this pathway may play a critical role in the progression and worsening of OCCC.

In this study, we investigated the combined effects of WX390, a dual inhibitor of PI3K/mTOR, and cisplatin on OCCC through both in vitro and in vivo experiments to further elucidate their therapeutic effects.

WX390 significantly inhibited the proliferation of human OCCC cell lines ES2 and OVISE, while promoting apoptosis. Furthermore, the combination of WX390 with CDDP exhibited a synergistic effect, markedly increasing the sensitivity of OCCC cells to chemotherapeutic agents and significantly suppressing tumor growth in PDX models. Western blot and RNA-seq analyses revealed that WX390 robustly inhibited the PI3K/AKT/mTOR pathway, interrupt autophagy, altered cell cycle dynamics, and induced apoptosis.

This study comprehensively assessed the efficacy of WX390 across multiple models of OCCC, laying a solid foundation for the development of new therapeutic strategies for this challenging malignancy.

ATR plays key roles in cellular responses to DNA damage and replication stress, a pervasive feature of cancer cells. ATR inhibitors (ATRi) are in clinical development for treating various cancers, including those with high replication stress, such as is elicited by ARID1A deficiency, but the cellular mechanisms that determine ATRi efficacy in such backgrounds are unclear. Here, we have conducted unbiased genome-scale CRISPR screens in ARID1A-deficient and proficient cells treated with ATRi. We found that loss of transcription factor KLF5 has severe negative impact on fitness of ARID1A-deficient cells while hypersensitising ARID1A-proficient cells to ATRi. KLF5 loss induced replication stress, DNA damage, increased DNA-RNA hybrid formation, and genomic instability upon ATR inhibition. Mechanistically, we show that KLF5 protects cells from replication stress, at least in part through regulating BRD4 recruitment to chromatin. Overall, our work identifies KLF5 as a potential target for eradicating ARID1A-deficient cancers.

The DNA damage response (DDR) is a network of proteins that coordinate DNA repair and cell-cycle checkpoints to prevent damage being transmitted to daughter cells. DDR defects lead to genomic instability, which enables tumour development, but they also create vulnerabilities that can be used for cancer therapy. Historically, this vulnerability has been taken advantage of using DNA-damaging cytotoxic drugs and radiotherapy, which are more toxic to tumour cells than to normal tissues. However, the discovery of the unique sensitivity of tumours defective in the homologous recombination DNA repair pathway to PARP inhibition led to the approval of six PARP inhibitors worldwide and to a focus on making use of DDR defects through the development of other DDR-targeting drugs. Here, we analyse the lessons learnt from PARP inhibitor development and how these may be applied to new targets to maximize success. We explore why, despite so much research, no other DDR inhibitor class has been approved, and only a handful have advanced to later-stage clinical trials. We discuss why more reliable predictive biomarkers are needed, explore study design from past and current trials, and suggest alternative models for monotherapy and combination studies. Targeting multiple DDR pathways simultaneously and potential combinations with anti-angiogenic agents or immune checkpoint inhibitors are also discussed.

Genomic instability has been proposed as a predictive biomarker for immunotherapy in ovarian cancer. We tested a method for measuring DNA damage, a direct measure of genomic instability, in ovarian tumors and its ability to predict immunotherapy response to Vigil (gemogenovatucel-T).

Eighty-two formalin-fixed paraffin-embedded tumors from the VITAL trial (NCT02346747) underwent DNA damage assessment using Repair Assisted Damage Detection (RADD). VITAL tested maintenance Vigil therapy vs. placebo for stage IIIB-IV newly diagnosed ovarian cancer in clinical complete response. DNA lesion levels determined by RADD were scored and assessed against patient survival outcomes, expression of CD39, and gene expression signatures.

A graduated distribution of RADD scores occurred across all 82 ovarian samples. RADD scores were able to predict HR status (p < 0.001). RADD demonstrated a significant Pearson's correlation with suggested Vigil biomarker CD39 (r = 0.473; p < 0.001), specifically within HRP tumors (r = 0.57; p = 0.002). High RADD scores correlated with worse recurrent free survival (RFS) in the placebo arm of the trial (7.9 vs. 14.7 months, high vs. low; p = 0.066). High RADD scores were also predictive of significant RFS over 39.4 months with Vigil compared to placebo (25.1 vs. 11.7 months, p = 0.005) and improved, but not significantly, OS with 38.8 vs. 31.8 months.

RADD revealed DNA repair proficiency without mutation signatures or expression profiling. High DNA damage levels show improved survival for Vigil maintenance therapies and are correlated with immune evasion proteins. The persistence of DNA lesions in the genomic DNA offers a new biomarker for immunotherapy patient stratification.

Mutation of genes related to the SWI/SNF chromatin remodeling complex is detected in 20% of all cancers. The SWI/SNF chromatin remodeling complex comprises about 15 subunits and is classified into three subcomplexes: cBAF, PBAF, and ncBAF. Previously, we showed that ovarian clear cell carcinoma cells deficient in ARID1A, a subunit of the cBAF complex, are synthetic lethal with several genes required for glutathione (GSH) synthesis and are therefore sensitive to the GSH inhibitor eprenetapopt (APR-246). However, we do not know whether cancer cells deficient in SWI/SNF components other than ARID1A are selectively sensitive to treatment with eprenetapopt. Here, we show that SMARCA4-, SMARCB1-, and PBRM1-deficient cells are more sensitive to eprenetapopt than SWI/SNF-proficient cells. We found that deficiency of SMARCA4, SMARCB1, or PBRM1 attenuates transcription of the SLC7A11 gene (which supplies cysteine as a raw metabolic material for GSH synthesis) by the failure of recruitment of cBAF and PBAF to the promotor and enhancer regions of the SLC7A11 locus, thereby reducing basal levels of GSH. In addition, eprenetapopt decreased the amount of intracellular GSH and increased the intracellular amount of reactive oxygen species (ROS), followed by induction of apoptosis. Taken together, eprenetapopt could be a promising selective agent for SWI/SNF-deficient cancer cells derived from SMARCA4-deficient lung cancers, SMARCB1-deficient rhabdoid tumors, and PBRM1-deficient kidney cancers.

Background: Endometrial cancer is strongly associated with obesity, and tumors often harbor mutations in major cancer signaling pathways. To inform the integration of body composition into targeted therapy paradigms, this hypothesis-generating study explores the association between muscle mass, body fat, and tumor proteomics. Methods: We analyzed data from 113 patients in The Cancer Genome Atlas (TCGA) and Cancer Proteomic Tumor Analysis Consortium (CPTAC) cohorts and their corresponding abdominal CT scans. Among these patients, tumor proteomics data were available for 45 patients, and 133 proteins were analyzed. Adiposity and muscle components were assessed at the L3 vertebral level on the CT scans. Patients were stratified into tertiles of muscle and fat mass and categorized into three groups: high muscle/low adiposity, high muscle/high adiposity, and low muscle/all adiposities. Linear and Cox regression models were adjusted for study cohort, stage, histology type, age, race, and ethnicity. Results: Compared with the high-muscle/low-adiposity group, both the high-muscle/high-adiposity (HR = 4.3, 95% CI = 1.0-29.0) and low-muscle (HR = 4.4, 95% CI = 1.3-14.9) groups experienced higher mortality. Low muscle was associated with higher expression of phospho-4EBP1(T37 and S65), phospho-GYS(S641) and phospho-MAPK(T202/Y204) but lower expression of ARID1A, CHK2, SYK, LCK, EEF2, CYCLIN B1, and FOXO3A. High muscle/high adiposity was associated with higher expression of phospho-4EBP1 (T37), phospho-GYS (S641), CHK1, PEA15, SMAD3, BAX, DJ1, GYS, PKM2, COMPLEX II Subunit 30, and phospho-P70S6K (T389) but with lower expression of CHK2, CRAF, MSH6, TUBERIN, PR, ERK2, beta-CATENIN, AKT, and S6. Conclusions: These findings demonstrate an association between body composition and proteins involved in key cancer signaling pathways, notably the PI3K/AKT/MTOR, MAPK/ERK, cell cycle regulation, DNA damage response, and mismatch repair pathways. These findings warrant further validation and assessment in relation to prognosis and outcomes in these patients.

SWI/SNF (Switch/Sucrose non-fermentable, switch/sucrose non-fermentable) chromatin remodeling complex is a macromolecular complex composed of multiple subunits. It can use the energy generated by the hydrolysis of ATP (Adenosine triphosphate) to destroy the connection between DNA and histones, achieve the breakdown of nucleosomes, and regulate gene expression. SWI/SNF complex is essential for cell proliferation and differentiation, and the abnormal function of its subunits is closely related to tumorigenesis. Among them, ARID1A, an essential non-catalytic subunit of the SWI/SNF complex, can regulate the targeting of the complex through DNA or protein interactions. Moreover, the abnormal function of ARID1A significantly reduces the targeting of SWI/SNF complex to genes and participates in critical intracellular activities such as gene transcription and DNA synthesis. As a catalytic subunit of the SWI/SNF complex, SMARCA4 has ATPase activity that catalyzes the hydrolysis of ATP to produce energy and power the chromatin remodeling complex, which is critical to the function of the SWI/SNF complex. The study data indicate that approximately 25% of cancers have one or more SWI/SNF subunit genetic abnormalities, and at least nine different SWI/SNF subunits have been identified as having repeated mutations multiple times in various cancers, suggesting that mutations affecting SWI/SNF subunits may introduce vulnerabilities to these cancers. Here, we review the mechanism of action of ARID1A and SMARCA4, the two subunits with the highest mutation frequency in the SWI/SNF complex, and the research progress of their targeted therapy in tumors to provide a new direction for precise targeted therapy of clinical tumors.

Endometriosis is a common estrogen-dependent inflammatory disease with a chronic course and a tendency to recur. The association between endometriosis and cancer has been studied for several years. Numerous reports have demonstrated a strong association between specific ovarian malignancies and endometriotic lesions. Atypical endometriosis has been widely described as a malignant precursor to ovarian epithelial tumors, particularly clear cell carcinomas and endometrioid carcinomas. These histological types associated with endometriosis develop predominantly in the ovary rather than in extragonadal sites. The detailed molecular mechanism of etiology remains unclear. Recent studies have analyzed the genetic and molecular mechanisms involved in endometriosis-associated ovarian cancer. A critical role appears to be played by a carcinogenic model based on iron-induced oxidative stress, which is typical of the endometriosis microenvironment. It has been hypothesized that trans-tubal reflux of blood, endometrial cells and associated iron-induced oxidative stress underlie the development of endometriosis-associated ovarian cancer. However, the multifactorial mechanisms of this malignant transformation are not fully understood. The aim of this review is to summaries the current epidemiological, histopathological, genetic and molecular findings in the progression of endometriosis-associated ovarian cancer.

Tumor energy metabolism plays a crucial role in the occurrence, progression, and drug resistance of tumors. The study of tumor energy metabolism has gradually become an emerging field of tumor treatment. Recent studies have shown that epigenetic regulation is closely linked to tumor energy metabolism, influencing the metabolic remodeling and biological traits of tumor cells. This review focuses on the primary pathways of tumor energy metabolism and explores therapeutic strategies to target these pathways. It covers key areas such as glycolysis, the Warburg effect, mitochondrial function, oxidative phosphorylation, and the metabolic adaptability of tumors. Additionally, this article examines the role of the epigenetic regulator SWI/SNF complex in tumor metabolism, specifically its interactions with glucose, lipids, and amino acids. Summarizing therapeutic strategies aimed at these metabolic pathways, including inhibitors of glycolysis, mitochondrial-targeted drugs, exploitation of metabolic vulnerabilities, and recent developments related to SWI/SNF complexes as potential targets. The clinical significance, challenges, and future directions of tumor metabolism research are discussed, including strategies to overcome drug resistance, the potential of combination therapy, and the application of new technologies.

Long non-coding RNAs (lncRNAs) have emerged as critical regulators of epigenome, modulating gene expression through DNA methylation, histone modification, and/or chromosome remodeling. Dysregulated lncRNAs act as oncogenes or tumor suppressors, driving tumor progression by shaping the cancer epigenome. By interacting with the writers, readers, and erasers of the epigenetic script, lncRNAs induce epigenetic modifications that bring about changes in cancer cell proliferation, apoptosis, epithelial-mesenchymal transition, migration, invasion, metastasis, cancer stemness and chemoresistance. This review analyzes and discusses the multifaceted role of lncRNAs in cancer pathobiology, from cancer genesis and progression through metastasis and therapy resistance. It also explores the therapeutic potential of targeting lncRNAs through innovative diagnostic, prognostic, and therapeutic strategies. Understanding the dynamic interplay between lncRNAs and epigenome is crucial for developing personalized therapeutic strategies, offering new avenues for precision cancer medicine.

ARID1A is a key component of the switch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex and functions as a critical tumor suppressor in various cancers. In this study, we find that tumor cells with hotspot missense mutations in ARID1A (AT-rich interactive domain-containing protein 1A) exhibit a malignant phenotype. Mechanistically, these mutations facilitate the translocation of ARID1A mutant proteins to the cytoplasm by the nucleocytoplasmic shuttler XPO1 (exportin 1). Subsequently, the E3 ubiquitin ligase STUB1 ubiquitinates the ARID1A mutant protein, marking it for degradation. Knocking down STUB1 or inhibiting XPO1 stabilizes the ARID1A mutant protein, retaining it in the nucleus, which restores the assembly of the cBAF complex, the chromatin remodeling function, and the normal expression of genes related to the MAPK and anti-apoptotic pathways, thereby decreasing the tumor burden. Our research shows that nuclear-localized mutated ARID1A proteins retain tumor-suppressive function. We identify promising strategies to treat cancers harboring missense mutations in the BAF complex.

Recent studies have revealed that the Sry-related HMG box gene 17 (SOX17) plays an important role in ovarian carcinogenesis. Unlike other types of ovarian cancer, ovarian clear cell carcinoma (OCCC) has a distinct pathobiological phenotype, often harboring an AT-rich interaction domain 1 A (ARID1A) mutation. In the present study, to determine the SOX17 in OCCC cells, we immunohistochemically examined SOX17 expression in 47 whole-tissue specimens of OCCC. Although not statistically significant, SOX17-high immunoreactivity tended to be related to unfavorable patient outcomes. We also aimed to determine the relationship of SOX17 with ARID1A. Double immunofluorescence staining demonstrated that SOX17 immunoreactivity was not associated with ARID1A immunoreactivity. Immunoblotting revealed that SOX17 was abundantly expressed in cultured OVISE and RMG-V OCCC cells, but not in OVTOKO OCCC cells. Polyubiquitinated bands of SOX17 were observed in MG132 treated OVTOKO, but not in OVISE or RMG-V OCCC cells. Notably, si-RNA-mediated knockdown of a deubiquitinase enzyme, ubiquitin C-terminal hydrolase L1, increased polyubiquitination followed by proteasome degradation of SOX17 in OVISE. These findings indicate that SOX17 is not uniformly and heterogeneously expressed in OCCCs, independent of ARID1A deficiency. Impaired ubiquitin-mediated proteasome degradation may stabilize SOX17 in some OCCC cells.

The tumor immune microenvironment in ovarian clear cell carcinoma has not been clearly defined. We analyzed the immunological changes from treatment-naive to recurrence to correlate them with clinical outcomes.

We compared the changes in immune infiltration of advanced-stage ovarian clear cell carcinoma samples before treatment and at the time of recurrence via immunohistochemistry (Programmed Cell Death-ligand 1 (PD-L1), cluster of differentiation 8 (CD8+), forkhead box P3 (Foxp3+)), tumor-infiltrating lymphocytes (TIL), and next-generation sequencing (54 patients). We analyzed the association between platinum sensitivity status and tumor immune microenvironment.

Immunohistochemistry revealed significantly increased PD-L1 (p=0.048) and CD8+T cells (p=0.022) expression levels after recurrence. No significant differences were observed in TIL density or Foxp3+T cells. There was no significant correlation between TIL, PD-L1, CD8+T cell, and Foxp3+T cell levels in treatment-naive tumors and survival outcomes. The most common genomic alterations were PIK3CA (41.7%) and ARID1A (41.7%) mutations. There were no differences in the immunological changes or survival outcomes according to PIK3CA and ARID1A mutations. Patients with recurrent platinum-sensitive disease showed higher TIL expression levels. There were no significant differences in PD-L1, CD8+T cells, or Foxp3+T cells between platinum-sensitive and platinum-resistant diseases.

We characterized the tumor immune microenvironment in patients with advanced-stage ovarian clear cell carcinoma. PD-L1 and CD8+T cell expression significantly increased after recurrence. Whether this could be used to select patients for immunotherapy in the recurrence setting should be investigated.

Endometriosis is a disease affecting approximately 10% of reproductive age women. Loss of the tumor suppressor gene AT-rich interactive domain-containing protein 1A (ARID1A) occurs in some endometriosis cases. Histone deacetylase 6 (HDAC-6) is an enzyme with implication in several diseases including different cancer types and immunological disorders, where it is involved in protein trafficking and degradation, cell shape, and migration. In ARID1A-deficient ovarian cancer increased HDAC-6 expression lead to apoptosis-inhibiting post-translational modification of p53. It is not known if HDAC-6 expression is also altered in ARID1A-deficient endometriosis. The aim of this study was to assess HDAC-6 expression in endometriotic lesions in correlation to ARID1A-status. Two tissue-microarrays with 168 endometriotic lesions, including ovarian (64/168, 38 %), peritoneal (66/168, 39 %) and deep-infiltrating (38/168, 23 %) subtypes, and 73 endometrium of women without endometriosis were assessed. Mean ARID1A immunoreactivity score (IRS) in endometriosis group was 10.83 (±2.36) and 10.78 (±1.94) in the epithelium and stroma, respectively, while the respective mean HDAC6 IRS were 9.16 (±2.76) and 5.94 (±2.88). The comparison of the HDAC6 expression between endometriosis subtypes showed higher expression in deep-infiltrating endometriosis, in both, epithelium (p = 0.032) and stroma (p = 0.007). In ARID1A negative cases, epithelial expression of HDAC6 was higher in endometriosis compared to women without endometriosis (p = 0.031), and this was also specifically observed in the subset of ovarian endometriosis (p = 0.037). There were no significant differences in the stromal expression of HDAC6. In conclusion, our results demonstrate a complex expression pattern of HDAC6 depending on ARID1A status in different endometriosis subtypes. Further studies on HDAC6 and ARID1A are important to elucidate mechanisms involved in malignant transformation of endometriosis.

The BAF chromatin remodeler regulates lineage commitment including cranial neural crest cell (CNCC) specification. Variants in BAF subunits cause Coffin-Siris syndrome (CSS), a congenital disorder characterized by coarse craniofacial features and intellectual disability. Approximately 50% of individuals with CSS harbor variants in one of the mutually exclusive BAF subunits, ARID1A/ARID1B. While Arid1a deletion in mouse neural crest causes severe craniofacial phenotypes, little is known about the role of ARID1A in CNCC specification. Using CSS-patient-derived ARID1A+/- induced pluripotent stem cells to model CNCC specification, we discovered that ARID1A-haploinsufficiency impairs epithelial-to-mesenchymal transition (EMT), a process necessary for CNCC delamination and migration from the neural tube. Furthermore, wild-type ARID1A-BAF regulates enhancers associated with EMT genes. ARID1A-BAF binding at these enhancers is impaired in heterozygotes while binding at promoters is unaffected. At the sequence level, these EMT enhancers contain binding motifs for ZIC2, and ZIC2 binding at these sites is ARID1A-dependent. When excluded from EMT enhancers, ZIC2 relocates to neuronal enhancers, triggering aberrant neuronal gene activation. In mice, deletion of Zic2 impairs NCC delamination, while ZIC2 overexpression in chick embryos at post-migratory neural crest stages elicits ectopic delamination from the neural tube. These findings reveal an essential ARID1A-ZIC2 axis essential for EMT and CNCC delamination.

The switch/sucrose non-fermentable (SWI/SNF) subfamily are evolutionarily conserved, ATP-dependent chromatin-remodelling complexes that alter nucleosome position and regulate a spectrum of nuclear processes, including gene expression, DNA replication, DNA damage repair, genome stability and tumour suppression. These complexes, through their ATP-dependent chromatin remodelling, contribute to the dynamic regulation of genetic information and the maintenance of cellular processes essential for normal cellular function and overall genomic integrity. Mutations in SWI/SNF subunits are detected in 25% of human malignancies, indicating that efficient functioning of this complex is required to prevent tumourigenesis in diverse tissues. During development, SWI/SNF subunits help establish and maintain gene expression patterns essential for proper cellular identity and function, including maintenance of lineage-specific enhancers. Moreover, specific molecular signatures associated with SWI/SNF mutations, including disruption of SWI/SNF activity at enhancers, evasion of G0 cell cycle arrest, induction of cellular plasticity through pro-oncogene activation and Polycomb group (PcG) complex antagonism, are linked to the initiation and progression of carcinogenesis. Here, we review the molecular insights into the aetiology of human malignancies driven by disruption of the SWI/SNF complex and correlate these mechanisms to their developmental functions. Finally, we discuss the therapeutic potential of targeting SWI/SNF subunits in cancer.

Endometrioid ovarian cancers (EOvC) are usually managed as serous tumors. In this study, we conducted a comprehensive molecular investigation to uncover the distinct biological characteristics of EOvC. This retrospective multicenter study involved patients from three European centers. We collected clinical data and formalin-fixed paraffin-embedded (FFPE) samples for analysis at the DNA level using panel-based next-generation sequencing and array-comparative genomic hybridization. Additionally, we examined mRNA expression using NanoString nCounter® and protein expression through tissue microarray. We compared EOvC with other ovarian subtypes and uterine endometrioid tumors. Furthermore, we assessed the impact of molecular alterations on patient outcomes, including progression-free survival (PFS) and overall survival (OS). Preliminary analysis of clinical data from 668 patients, including 86 (12.9%) EOvC, revealed more favorable prognosis for EOvC compared with serous ovarian carcinoma (5-year OS of 60% versus 45%; P = 0.001) driven by diagnosis at an earlier stage. Immunohistochemistry and copy number alteration (CNA) profiles of 43 cases with clinical data and FFPE samples available indicated that EOvC protein expression and CNA profiles were more similar to endometrioid endometrial tumors than to serous ovarian carcinomas. EOvC exhibited specific alterations, such as lower rates of PTEN loss, mutations in DNA repair genes, and P53 abnormalities. Survival analysis showed that patients with tumors harboring loss of PTEN expression had worse outcomes (median PFS 19.6 months vs. not reached; P = 0.034). Gene expression profile analysis confirmed that EOvC differed from serous tumors. However, comparison to other rare subtypes of ovarian cancer suggested that the EOvC transcriptomic profile was close to that of ovarian clear cell carcinoma. Downregulation of genes involved in the PI3K pathway and DNA methylation was observed in EOvC. In conclusion, EOvC represents a distinct biological entity and should be regarded as such in the development of specific clinical approaches.

Ovarian clear cell carcinoma rarely responds to second-line chemotherapy, the recommended treatment for relapsed epithelial ovarian cancer. Here, we report the activity and safety of sintilimab in combination with bevacizumab in patients with relapsed or persistent ovarian clear cell carcinoma.

In the prospective, multicentre, single-arm, phase 2 INOVA trial, patients aged 18-75 years with histologically confirmed relapsed or persistent ovarian clear cell carcinoma were enrolled from eight tertiary hospitals in China. Eligible patients had an Eastern Cooperative Oncology Group performance status score of 0-2 and previous exposure to at least one cycle of platinum-containing chemotherapy. Enrolled patients received sintilimab (200 mg) and bevacizumab (15 mg/kg) intravenously every 3 weeks until disease progression. The primary endpoint was objective response rate assessed by independent central review based on Response Evaluation Criteria in Solid Tumours version 1.1. Eligible enrolled patients who received at least one cycle of treatment and had at least one tumour response assessment following the baseline assessment per protocol were included in the activity analysis. Patients who received at least one dose of study drug were included in the safety analysis. The study is registered with ClinicalTrials.gov (NCT04735861) and is ongoing.

Between April 8, 2021, and July 3, 2023, 51 patients were screened and 41 patients received at least one dose of sintilimab in combination with bevacizumab. Response evaluation was completed in 37 patients. Objective responses were observed in 15 patients (objective response rate 40·5%; 95% CI 24·8-57·9), of which five (14%) were complete responses and ten (27%) were partial responses. At data cutoff (Jan 29, 2024), the median follow-up was 16·9 months (IQR 7·5-23·4). Three (7%) patients developed grade 3 treatment-related adverse events including one patient with proteinuria, one patient with myocarditis, and one patient with rash. No treatment-related adverse events of worse than grade 3 severity were recorded. Treatment-related serious adverse events occurred in two (5%) patients including one patient with immune-related myocarditis and another with hypertension and renal dysfunction. No treatment-related deaths occurred.

Sintilimab in combination with bevacizumab showed promising anti-tumour activity and manageable safety in patients with relapsed or persistent ovarian clear cell carcinoma. Larger, randomised trials are warranted to compare this low-toxicity, chemotherapy-free combinatorial regimen with standard chemotherapy.

National Key Technology Research and Development Program of China, National Natural Science Foundation of China, Beijing Xisike Clinical Oncology Research Foundation, and Innovent Biologics.

For the Chinese translation of the abstract see Supplementary Materials section.