17α-hydroxylase/17,20-lyase deficiency (17OHD) is a rare autosomal recessive condition. Women who have the complete form of 17OHD typically have a female phenotype, with an absence of secondary sexual characteristics, primary amenorrhea, and hypertension, which is usually detected in adolescence. Generally, 46,XY patients with a partial form of 17OHD have atypical genitalia and intra-abdominal or inguinal testes. The risk of developing malignant testicular tumors or testicular adrenal rest tumors in 21-hydroxylase deficiency congenital adrenal hyperplasia is reported in 46,XY patients. In contrast, these conditions are rarely described in patients with 17OHD.

This study aims to investigate patients with 17OHD who exhibit testicular tumors and spontaneous pubertal development.

Two unrelated women with 46,XY karyotype with 17OHD who presented with unexpected spontaneous development of secondary sexual characteristics and testicular tumors were described. Pathogenic allelic variants in CYP17A1 were identified in the compound heterozygous state in both patients. The variants p.Trp406Arg and p.Pro428Leu were identified in the patient with Leydig cell neoplasia plus germ cell neoplasia in situ, and the p.Arg358Gln and p.Trp406Arg variants were identified in the patient with intratubular seminoma associated with invasive classic seminoma.

Our findings reinforce the risk of testicular tumor development among 46,XY patients with 17OHD and add data to the discussion of the risk/benefit ratio of prophylactic gonadectomy in the treatment patients with 46, XY differences in sex development (DSD).

Pediatric germ cell tumors represent a rare but biologically diverse group of neoplasms arising from pluripotent primordial germ cells. The 2022 edition of the WHO Classification of Pediatric Tumors introduced the first organ independent classification of germ cell tumors, reflecting advances in molecular biology, histopathology, and clinical practice. This review highlights the key changes, including the refined distinctions between the different subtypes. These updates enhance diagnostic accuracy and provide a framework for understanding age-dependent differences in tumor biology and behavior. Emphasis is placed on integrating the new classification into multidisciplinary care, particularly in addressing diagnostic challenges in pre- and post-pubertal-type germ cell tumors. By bridging the gap between histopathology and oncology, the updated classification represents a pivotal step forward in improving outcomes for children with germ cell tumors.

Pediatric ovarian tumors exhibit unique diagnostic and therapeutic challenges. This study evaluates the expression of SALL4 and OCT3/4 biomarkers in pediatric ovarian tumors and their associations with tumor subtype, stage, and clinical outcome. A retrospective analysis was conducted on 64 patients under 18 years old, examining demographic data, tumor characteristics, immunohistochemical staining, and clinical outcomes. Our results show that SALL4 was significantly expressed in adenocarcinoma, dysgerminoma (DSG), mixed germ cell tumors (GCTs), and immature teratoma, while OCT3/4 was highly expressed in DSG and mixed GCTs. Both markers are associated with a higher tumor grade and stage, indicating a more aggressive disease. The SALL4 positivity expression was correlated with high alpha fetoprotein (AFP) and lactate dehydrogenase (LDH) levels, while OCT3/4 positivity significantly predicted the risk of subsequent metastasis. The mean progression-free survival (PFS) was notably shorter in patients with positive markers. These findings underscore the diagnostic and prognostic value of SALL4 and OCT3/4 in pediatric ovarian tumors, aligning with previous research and supporting their use in clinical practice for better disease management and patient outcomes.

Ovarian tumors in the pediatric population are rare. The incidence and frequency of subtypes differ between children and adults. Although not all tumors are aggressive, they may still lead to morbidity. The goal of this study was a comprehensive review of malignant ovarian tumors in children and adolescents diagnosed and registered in Sweden.

Individuals were identified through a search in the National Cancer Register, limited for ages 0-19, years 1970-2014. Stored tumor diagnostic material from regional biobanks was retrieved and reviewed.

The study includes 345 individuals with ovarian tumors and 70.7% of them were between 15 and 19 years at time of diagnosis. No differences in incidence over time or geographic location were identified. The average follow-up time was 21.2 years and 5-year survival was 88.4%. Survival was similar in the different time periods, except for 1970-1979. Review was possible for 260 cases, resulting in 85 epithelial tumors, 121 GCTs, 47 SCSTs and 7 others. For age 0-4 years SCSTs dominated (85.7%), for 5-9- and 10-14-years GCTs dominated (70,8% and 75.0% respectively), and for age 15-19 years epithelial tumors dominated (43.8%). There was a strong agreement between review diagnosis and original diagnosis (Cohen's κ 0.944). Differentiating between entities within the sex cord-stromal group posed the biggest diagnostic challenge.

Ovarian tumors in children and adolescents are rare and distinct from their adult counterparts regarding incidence and frequency. There was a strong concurrence between original and review diagnoses. The greatest diagnostic difficulty was subtyping of epithelial tumors and differentiating between tumors within the SCST group.

Intrahepatic cholangiocarcinoma (ICCA) is a malignant epithelial neoplasm characterized by biliary differentiation within the liver. ICCA is molecularly heterogeneous and exhibits a broad spectrum of histopathological features. It is a highly aggressive carcinoma with high mortality and poor survival rates. ICCAs are classified into two main subtypes: the small-duct type and large-duct types. These two tumor types have different cell origins and clinicopathological features. ICCAs are characterized by numerous molecular alterations, including mutations in KRAS, TP53, IDH1/2, ARID1A, BAP1, BRAF, SAMD4, and EGFR, and FGFR2 fusion. Two main molecular subtypes-inflammation and proliferation-have been proposed. Recent advances in high-throughput assays using next-generation sequencing have improved our understanding of ICCA pathogenesis and molecular genetics. The diagnosis of ICCA poses a significant challenge for pathologists because of its varied morphologies and phenotypes. Accurate diagnosis of ICCA is essential for effective patient management and prognostic determination. This article provides an updated overview of ICCA pathology, focusing particularly on molecular features, histological subtypes, and diagnostic approaches.

Malignant germ cell tumours are a group of rare cancers whose incidence peaks in late adolescence and early adulthood. Dysgerminomas of the ovary and seminomas of the testis are analogous diseases, but seminomas have a 10-fold higher incidence. The two tumours are morphologically identical and are only differentiated by surrounding organ-specific tissue or testicular germ cell neoplasia in situ. They share genetic features including KIT and RAS mutations, amplification of chromosome 12p, and expression of pluripotency markers (NANOG (Nanog homeobox), OCT3/4 (Octamer-binding transcription factor 3/4), and SAL4 (Spalt-like trascription factor 4)). Both histologies are exquisitely sensitive to platinum chemotherapy, and the combination of bleomycin, etoposide, and cisplatin (BEP) yields survival rates greater than 90%. However, BEP causes significant, lifelong toxicity (cardiovascular, renal, respiratory, and neurological) in these young patients with an expectation of cure. Here, we comprehensively review the biological features of dysgerminoma and seminoma to demonstrate that they are biologically analogous diseases. We present available clinical trial data supporting de-escalation of chemotherapy treatment. Finally, we propose that future trials should enrol men, women, and children to benefit all patients regardless of age or sex.

We report a case of dysgerminoma in a 22-year-old woman diagnosed with chromosomal abnormality, balanced translocation 46X,t(X:1)(q22;q21). She had received hormone replacement therapy for 7 years for primary amenorrhea. She visited a primary care physician because of lower abdominal distension, and a large tumor in the pelvis was discovered. She was admitted to our hospital for further examination of the pelvic tumor. She underwent laparotomy and was diagnosed with stage IIIA1 dysgerminoma (pT3apN0pM0) of the left ovary. Young female patients without the Y chromosome who are treated for primary amenorrhea may also develop malignant germ cell tumors; therefore, gynecologists should provide hormone replacement therapy and periodic pelvic evaluation.

The pathways of gametogenesis encompass elaborate cellular specialization accompanied by precise partitioning of the genome content in order to produce fully matured spermatozoa and oocytes. Transcription factors are an important class of molecules that function in gametogenesis to regulate intrinsic gene expression programs, play essential roles in specifying (or determining) germ cell fate and assist in guiding full maturation of germ cells and maintenance of their populations. Moreover, in order to reinforce or redirect cell fate in vitro, it is transcription factors that are most frequently induced, over-expressed or activated. Many reviews have focused on the molecular development and genetics of gametogenesis, in vivo and in vitro, in model organisms and in humans, including several recent comprehensive reviews: here, we focus specifically on the role of transcription factors. Recent advances in stem cell biology and multi-omic studies have enabled deeper investigation into the unique transcriptional mechanisms of human reproductive development. Moreover, as methods continually improve, in vitro differentiation of germ cells can provide the platform for robust gain- and loss-of-function genetic analyses. These analyses are delineating unique and shared human germ cell transcriptional network components that, together with somatic lineage specifiers and pluripotency transcription factors, function in transitions from pluripotent stem cells to gametes. This grand theme review offers additional insight into human infertility and reproductive disorders that are linked predominantly to defects in the transcription factor networks and thus may potentially contribute to the development of novel treatments for infertility.

One-hundred fourty pure dysgerminomas were evaluated with particular focus on the microscopic features as seen in 125 cases with available slides. The patients ranged from 8 to 59 years of age (mean, 24.1 y). The tumors, bilateral in 4% of the cases and with a mean tumor diameter of 13 cm, were typically soft, lobulated, homogeneous, and creamy white to tan to yellow but necrosis was found in 13%, hemorrhage in 20%, and focal cystic change in 15%. On microscopic examination, the patterns and other notable features encountered, including their frequency, were as follows: an alveolar pattern resulting from delicate fibrovascular septa (51%), diffuse (33%), macronodular (14%), insular (26%), cords (28%), solid tubular (17%), microspaces (sometimes simulating glands) (12%), follicle-like spaces (5%), prominent fibrous bands (65%), stromal edema (56%), stromal luteinization (9%), granulomatous infiltrate (46%), lymphocytic infiltrate (100%), Langhans cell type giant cells (35%), syncytiotrophoblast giant cells (6%), prominent population of cells with pale to clear cytoplasm (73%), cells with amphophilic to eosinophilic cytoplasm (53%) and vacuolated occasionally signet ring-like cells (7%). Various constellations of the above findings often resulted in an appearance different from that usually portrayed in the literature and certain tumors of very different nature being in the differential such as undifferentiated carcinoma not otherwise specified, small cell carcinoma of hypercalcemic type, and malignant lymphoma. The correct diagnosis can be arrived at by considering the usual relative youth of the patient, often rather characteristic gross features, and most crucially careful attention to the microscopic features and awareness of variant morphologic findings. Those that are particularly problematic based on this study are diffuse growth with inconspicuous fibrovascular septa, macronodules, cords, solid tubular formations, spaces ranging from small to large, and mimicking glands or follicles, prominent fibrous to edematous stroma, and cells with amphophilic to eosinophilic cytoplasm. According to the degree of difficulty and confidence of the interpreter, well-known immunohistochemical features of dysgerminoma, which largely differ from those of other neoplasms in the differential, will aid if felt indicated.

Malignant ovarian germ cell tumors (MOGCTs) are rare and heterogeneous ovary tumors. We aimed to identify potential germline mutations and somatic mutations in MOGCTs by whole-exome sequencing. The peripheral blood and tumor samples from these patients were used to identify germline mutations and somatic mutations, respectively. For those genes with copy number alterations (deletion and duplication region), functional annotation was performed. Immunohistochemistry was performed to evaluate the expression of mutated genes corresponding to CNA deletion region and duplication region. In peripheral blood, copy number loss and gain were mostly found in yolk sac tumors (YSTs). Moreover, POU5F1 was the most significant mutated gene with mutation frequency >10% in both CNA deletion and duplication region. In addition, strong cytoplasm staining of POU5F1 (corresponding to CNA deletion region and duplication region) was found in two YST and nuclear staining in two dysgerminomas tumor samples. Genes corresponding to CNA deletion region were significantly enriched in the signaling pathway of regulating pluripotency of stem cells. In addition, genes corresponding to CNA duplication region were significantly enriched in the signaling pathways of RIG-I (DExD/H-box helicase 58)-like receptor, Toll-like receptor and nuclear factor (NF)-kappa. Keratin 4 (KRT4), ribosomal protein L14 (RPL14), proprotein convertase subtilisin/kexin type 6 (PCSK6), poly(A)-binding protein cytoplasmic 3 (PABPC3), and sterile alpha and TIR motif containing 1 (SARM1) mutations were detected in both peripheral blood and tumor samples. Identification of potential germline mutations and somatic mutations in MOGCTs may provide a new field in understanding the genetic feature of the rare biological tumor type in the ovary.

Germ cell tumors (GCT) in men comprise of tumor subtypes with distinct histomorphologies, genetic and genomic alterations, and clinical behavior. Immunohistochemical (IHC) markers, including many newly described nuclear transcription factors, are often applied in challenging cases to arrive at a correct diagnosis and classification, and to establish germ cell origin for metastatic tumors. However, there is no established role for IHC markers in prognosis and therapy response prediction in GCTs. This chapter briefly reviews the clinical utility of IHC in diagnosis and classification of GCTs, including technical aspects of performing IHC and clinical applications of commonly used IHC markers in the workup of common and clinically relevant diagnostic scenarios.

Dysgerminomas are rare malignant germ cell tumors. They usually arise from the ovary, but case reports describing extraovarian dysgerminomas do exist. When treated adequately the disease has a good prognosis. Dysgerminomas diagnosed during pregnancy are very rare.

Report of extraovarian intra-abdominal dysgerminoma during pregnancy. Systematic literature review.

A 35-year-old second gravida was diagnosed with a suspected intra-abdominal mass at 20 gestational weeks. During an exploratory laparotomy, a tumor infiltrating the transverse colon and histologically identified as a dysgerminoma was resected. Ovaries were clinically unremarkable. The induction of chemotherapy was postponed until after delivery. At 34 gestational weeks the patient underwent cesarean section and tumor debulking. Four cycles of bleomycin, etoposide and cisplatin were administered. After 12 months, cystic ovaries were found. Hysterectomy with bilateral adnexectomy was performed but no malignancy found. After 16 months, the patient was still in complete remission.

We describe the first-ever published dysgerminoma in gravida primarily evolving intraabdominally and not affecting the ovaries. The decision for cytoreductive surgery, prolongation of pregnancy and postponing chemotherapy until after delivery combined the best benefit for the baby with a good maternal prognosis. Due to limited data regarding dysgerminomas in pregnancy, individual interdisciplinary concepts are mandatory.

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Neuroblastic tumours (NBTs) are paediatric solid tumours derived from embryonic neural crest cells which harbour their own cancer stem cells (CSC). There is evidence indicating that CSC may be responsible for tumour progression, chemotherapy resistance and recurrence in NBTs. Oct4 is a transcription factor which plays a key role in mammal embryonic development and stem cell fate regulation. The aim of the study is to elucidate the clinical significance of Oct4 in NBTs.

We studied Oct4 expression in 563 primary NBTs using digital image quantification. Chi-square test was applied to analyse the correlation between histopathology and the Oct4+ cell percentage. Survival analysis was carried out with Kaplan-Meier curves and log-rank test. Additionally, a multivariate Cox regression analysis with the stepwise backwards (Wald) method was undertaken to calculate the impact of Oct4 expression level on survival.

We found that tumours with a high proportion of cells expressing Oct4 correlated statistically with undifferentiated and poorly differentiated neuroblastoma / nodular ganglioneuroblastoma, and that Oct4 expression was not present in ganglioneuroma (p < 0.05). Statistical analysis also indicated a relationship between high Oct4 expression levels, high-risk patients according to the International Neuroblastoma Risk Group pre-treatment classification parameters, larger blood vessels and low survival rates.

These results suggest that the Oct4 gene may regulate NBT pathogenic differentiation pathways, and should thus be considered as a target for knockdown when developing novel therapies for high-risk NBT patients.

OCT4 and SALL4 are transcription factors within a complex network that functions to maintain pluripotency in primitive stem cells and germ cells. Nuclear expression of OCT4 is widely cited as sensitive and specific for primary and metastatic germ cell tumors and is commonly used in the diagnosis of central nervous system (CNS) germinomas. Studies have failed to systematically examine the expression of OCT4 or SALL4 in diffuse large B-cell lymphoma (DLBCL), although this entity enters the morphologic differential diagnosis of some germ cell tumors. A retrospective review was conducted on 145 consecutive cases of DLBCL and testicular lymphoma to evaluate the prevalence of OCT4 and SALL4 expression. Nuclear OCT4 expression was present in 2/11 (18%) testicular DLBCLs and 6/134 (4.5%) nontesticular DLBCLs. Most OCT4 cases demonstrated moderate to strong expression in >50% of neoplastic cells. Rare, weak nuclear SALL4 expression was detected in only 3 nontesticular DLBCLs. Within the extratesticular DLBCL group, 2/6 (33%) primary CNS DLBCLs expressed nuclear OCT4. In addition, OCT4 DLBCL showed an overall predilection toward non-germinal center B-cell phenotype (7/8; 88%) and had a higher than expected rate of CD5 coexpression (4/8, 50%). These results are cautionary against using OCT4 as a sole marker of germ cell differentiation in testicular and extratesticular sites, especially in the CNS. The apparent associations of OCT4 expression with primary CNS DLBCL, non-germinal center B-cell phenotype, and CD5 coexpression raise the question of whether OCT4 expression in DLBCL may reflect more aggressive biology.

A 46 XY pure gonadal dysgenesis also known as Swyer syndrome. These patients are phenotypic females with normal female external genitalia and absent testicular tissue. The patients with swyer syndrome have streak gonads and increased risk of dysgerminoma and gonadoblastoma. We present a case of dysgerminoma in dysgenetic gonads of swyer syndrome. A 23-year-old female had come with complaints of primary amenorrhea, pelvic mass and abdominal pain. Clinical findings, pathology investigation and imaging findings revealed swyer syndrome. On MRI it showed a large lobulated mass in the pelvis. Mass was excised and dysgerminoma was given on the histopathology.

Hepatocellular carcinoma (HCC) is one of the most common cancers, and is also the leading cause of death worldwide. Studies have shown that cellular reprogramming contributes to chemotherapy and/or radiotherapy resistance and the recurrence of cancers. In this article, we summarize and discuss the latest findings in the area of cellular reprogramming in HCC. The aberrant expression of transcription factors OCT4, KLF4, SOX2, c-MYC, NANOG, and LIN28 have been also observed, and the expression of these transcription factors is associated with unfavorable clinical outcomes in HCC. Studies indicate that cellular reprogramming may play a critical role in the occurrence and recurrence of HCC. Recent reports have shown that DNA methylation, miRNAs, tumor microenvironment, and signaling pathways can induce the expression of stemness transcription factors, which leads to cellular reprogramming in HCC. Furthermore, studies indicate that therapies based on cellular reprogramming could revolutionize HCC treatment. Finally, a novel therapeutic concept is discussed: reprogramming control therapy. A potential reprogramming control therapy method could be developed based on the reprogramming demonstrated in HCC studies and applied at two opposing levels: differentiation and reprogramming. Our increasing understanding and control of cellular programming should facilitate the exploitation of this novel therapeutic concept and its application in clinical HCC treatment, which may represent a promising strategy in the future that is not restricted to liver cancer.

Octamer-binding transcription factor 4 (OCT4) is a key regulatory gene that maintains the pluripotency and self-renewal properties of embryonic stem cells. Although there is emerging evidence that it can function as oncogene in several cancers, the role in mediating cervical cancer remains unexplored. Here we found that OCT4 protein expression showed a pattern of gradual increase from normal cervix to cervical carcinoma in situ and then to invasive cervical cancer. Overexpression of OCT4 in two types of cervical cancer cells promotes the carcinogenesis, and inhibits cancer cell apoptosis. OCT4 induces upregulation of miR-125b through directly binding to the promoter of miR-125b-1 confirmed by chromatin immunoprecipitation analysis. MiRNA-125b overexpression suppressed apoptosis and expression of BAK1 protein. In contrast, miR-125b sponge impaired the anti-apoptotic effect of OCT4, along with the upregulated expression of BAK1. Significantly, Luciferase assay showed that the activity of the wild-type BAK1 3'-untranslated region reporter was suppressed and this suppression was diminished when the miR-125b response element was mutated or deleted. In addition, we observed negative correlation between levels of BAK1 and OCT4, and positive between OCT4 and miR-125b in primary cervical cancers. These findings suggest an undescribed regulatory pathway in cervical cancer, by which OCT4 directly induces expression of miR-125b, which inhibits its direct target BAK1, leading to suppression of cervical cancer cell apoptosis.

This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors.

Epithelial ovarian cancer (EOC) remains the most lethal of all the gynaecological malignancies with drug resistance and recurrence remaining the major therapeutic barrier in the management of the disease. Although several studies have been undertaken to understand the mechanisms responsible for chemoresistance and subsequent recurrence in EOC, the exact mechanisms associated with chemoresistance/recurrence continue to remain elusive. Recent studies have shown that the parallel characteristics commonly seen between embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSC) are also shared by a relatively rare population of cells within tumors that display stem cell-like features. These cells, termed 'cancer initiating cells' or 'cancer stem cells (CSCs)' have been shown not only to display increased self renewal and pluripotent abilities as seen in ESCs and iPSCs, but are also highly tumorigenic in in vivo mouse models. Additionally, these CSCs have been implicated in tumor recurrence and chemoresistance, and when isolated have consistently shown to express the master pluripotency and embryonic stem cell regulating gene Oct4. This article reviews the involvement of Oct4 in cancer progression and chemoresistance, with emphasis on ovarian cancer. Overall, we highlight why ovarian cancer patients, who initially respond to conventional chemotherapy subsequently relapse with recurrent chemoresistant disease that is essentially incurable.

Clear cell carcinoma has a storied history in the female genital tract. From the initial designation of ovarian clear cell adenocarcinoma as "mesonephroma" to the linkage between vaginal clear cell carcinoma and diethylstilbestrol exposure in utero, gynecologic tract clear cell tumors have puzzled investigators, posed therapeutic dilemmas for oncologists, and otherwise presented major differential diagnostic challenges for pathologists. One of the most common errors in gynecologic pathology is misdiagnosis of clear cell carcinoma, on both frozen section and permanent section. Given the poor response to platinum-based chemotherapy for advanced-stage disease and increased risk of thromboembolism, accurate diagnosis of clear cell carcinoma is important in the female genital tract. This review (1) presents the clinical and pathologic features of female genital tract clear cell carcinomas; (2) highlights recent molecular developments; (3) identifies areas of potential diagnostic confusion; and (4) presents solutions for these diagnostic problems where they exist.

Ovarian yolk sac tumour (OYST) is a very rare malignancy arising most often in young women. Preoperative clinical, biological (alpha-foetoprotein) and radiological findings should help to establish the diagnosis of OYST, in order to propose adequate surgical treatment. The aim of surgery is to remove the primary tumour, to obtain an accurate histological diagnosis and to assess the disease extent. In young women, fertility-sparing surgery should be performed, in order to preserve the possibility of pregnancy later on. Chemotherapy has substantially modified the prognosis of these tumours, and practically all patients will be cured. The overall 5-year survival rate is 94% when patients are treated with BEP chemotherapy. Depending on the clinical situation, two to four cycles of the BEP regimen should be administered after surgery. Identification of prognostic factors may help to propose risk-adapted treatment in order to increase the cure rate in patients with a poor prognosis and to decrease toxicity in patients with a low risk of relapse. Fertility preservation represents a major objective in women treated for OYSTs.

A seven-year-old female cynomolgus monkey had a mass in the left ovary with metastasis to the lung and the right ovary. The mass of these organs showed three different characteristics, and its immunohistochemical profiles were consistent with embryonal carcinoma (EC), choriocarcinoma (CC), and epithelioid trophoblastic tumor (ETT). The EC was characterized with sheets and glandlike structures with large pleomorphic, single-nucleated epithelial cells that were immunohistochemically positive for α-fetoprotein, octamer-4, and CD30, and with multinucleated giant cells resembling syncytiotrophoblasts. The CC also represented biphasic proliferation of the cytotrophoblast positive for cytokeratin 7 (CK7), which showed negative immunoreactivity for all three of the above antibodies, and it was syncytiotrophoblast positive for human chorionic gonadotropin. The ETT showed numerous floating cells in an abundant eosinophilic extracellular matrix with vacuolated or eosinophilic cytoplasm and was immunohistochemically positive for CK7, p63, and α-inhibin, which features nodule or cordlike structures. Collectively, this neoplasm was identified as a mixed germ cell tumor with EC, CC, and ETT. To our knowledge, this is the first report of EC in nonhuman primates as a component of mixed germ cell tumor.

The Octamer 4 gene (Oct4) is a master pluripotency controller that has been detected in several types of tumors. Here, we examine the expression of Oct4 in human esophageal squamous cell carcinoma (ESCC). We found that punctate Oct4 protein was expressed in most (93.7%) ESCC samples but it was not observed in esophageal mucosa. Some ESCC cells had the capacity to form tumorospheres; those with an Oct4(+)-rich cell phenotype had increased proliferation and Oct4 mRNA levels compared to those of differentiated cells in culture or xenograft tumors. The over-expression of Oct4 in ESCCs suggests that it is a potential target for ESCC therapy. Oct4 could be a useful tumor marker in an immunohistochemical panel designed to differentiate between ESCC and esophageal mucosa. Expression of Oct4 in tumorospheres might indicate the presence of a population of ECSCs and its expression in xenograft tumors suggests that Oct4 is also associated with tumor metastasis.

OCT3/4, NANOG, SOX2 and, most recently, LIN28 have been identified as key regulators of pluripotency in mammalian embryonic and induced stem cells, and are proven to be crucial for generation of the mouse germ-cell lineage. These factors are a hallmark of certain histological types of germ-cell tumours (GCTs). Here, we report novel information on the temporal and spatial expression pattern of LIN28 during normal human male germ-cell development as well as various types of GCTs. To investigate LIN28 expression, immunohistochemical analyses and quantitative proximity ligation assay-based TaqMan protein assays were applied on snap-frozen and formalin-fixed, paraffin-embedded samples as well as representative cell lines. LIN28 was found in primordial germ cells, gonocytes and pre-spermatogonia, in contrast to OCT3/4 and NANOG, which were found only in the first two stages. LIN28 was also found in all precursor lesions (carcinoma in situ and gonadoblastoma) of type II GCTs, as well as the invasive components seminoma and the non-seminomatous elements embryonal carcinoma and yolk sac tumour. Choriocarcinoma showed a heterogeneous pattern, while teratomas and spermatocytic seminomas (type III GCTs) were negative. This expression pattern suggests that LIN28 is associated with malignant behaviour of type II GCTs. Cell line experiments involving siRNA knockdown of LIN28, OCT3/4 and SOX2 showed that LIN28 plays a role in the maintenance of the undifferentiated state of both seminoma and embryonal carcinoma, closely linked to, and likely upstream of OCT3/4 and NANOG. In conclusion, LIN28 regulates the differentiation status of seminoma and embryonal carcinoma and is likely to play a related role in normal human germ-cell development.

Conflicting results of studies on mouse and human have either verified or refuted the presence of oogonia/primordial germ cells in the post-natal ovary. The aim of this study was to trace whether oogonia recognized by immunohistochemical methods in the first trimester human ovary were present also in peri- and post-natal ovaries.

For this study, 82 human ovaries were collected: 25 from embryos from 5 to 10 weeks post conception (wpc), 2 at 18 wpc, 32 from 32 wpc to 2 years and 23 from 2 to 32 years. Of these, 80 ovaries were fixed and paraffin-embedded and 2 (8 year-old) ovaries were processed for plastic sections. Serial sections were prepared for immunohistochemical detection of markers for oogonia: tyrosine kinase receptor for stem cell factor (SCF)(C-KIT), stage-specific embryonic antigen-4 (SSEA4), homeobox gene transcription factor (NANOG), octamer binding transcription factor 4 (OCT4) and melanoma antigen-4 (Mage-A4), while noting that C-KIT also stains diplotene oocytes.

Almost all oogonia exclusively stained for SSEA4, NANOG, OCT4 and C-KIT, whereas MAGE-A4 only stained a small fraction. At birth only a few oogonia were stained. These disappeared before 2 years, leaving only diplotene oocytes stained for C-KIT. From 18 wpc to 2 years, the medulla contained conglomerates of healthy and degenerating oogonia and small follicles, waste baskets (WBs) and oogonia enclosed in growing follicles (FWB). Medulla of older ovaries contained groups of primordial, healthy follicles.

We found no evidence for the presence of oogonia in the human ovary after their final clearing during the first 2 years. We suggest that perinatal medullary WB and FWB give rise to the groups of small, healthy follicles in the medulla.

This report describes a case of dysgerminoma in a 21-year-old eastern rosella (Platycercus eximius eximius) that presented with dyspnea and a severely distended coelom. The bird was euthanatized, and a large, left-sided coelomic mass was identified. Microscopically, the mass was composed of sheets and nests of round to polygonal neoplastic cells with lacy cytoplasm. The neoplastic cells were weakly positive for vimentin and c-kit but negative for pancytokeratin, AE1, and inhibin. On the basis of the histomorphology and immunoreactivity, the neoplasm was determined to be a dysgerminoma. The variability of histologic appearance and immunohistochemical staining of dysgerminomas in humans compared with veterinary species is discussed.

Recent advances in the understanding of the molecular pathology of testicular tumours have led to the identification of several new immunohistochemical markers for invasive and in situ germ cell neoplasms. OCT3/4 and NANOG are nuclear stains that have high sensitivity and specificity for the identification of intratubular germ cell neoplasia as well as seminoma and embryonal carcinoma. A potential pitfall in their application to the detection of intratubular germ cell neoplasia, as in other markers that represent oncofetal antigens, is their expression in non-neoplastic germ cells with 'delayed maturation'. SALL4, another nuclear stain, is positive for most germ cell tumours as a group and may be especially helpful in the distinction of these tumours from somatic carcinomas in non-testicular sites. Glypican 3 is a more sensitive marker for yolk sac tumour than alpha-fetoprotein. SOX2 and SOX17 may be useful for differentiating seminoma and embryonal carcinoma, especially following chemotherapy as embryonal carcinoma may lose CD30 expression in this setting. This article reviews the application of these immunohistochemical markers and others to the diagnosis of germ cell neoplasia with reference to older immunohistochemical stains when appropriate. Suggested immunohistochemical panels are described for individual tumour types.

Primary mediastinal germ cell tumors (GCTs) are rare and sometimes they pose diagnostic difficulty without immunohistochemical studies. Here, we investigated the diagnostic utility of 6 stem cell markers (SCMs) SALL4, OCT4, NANOG, SOX2, UTF1, and TCL1 in 16 primary mediastinal seminomas, 3 embryonal carcinomas (ECs), 10 yolk sac tumors (YSTs), 7 teratomas (4 mature, 3 immature), and 1 choriocarcinoma. The percentage of tumor cells stained was scored as: 0 (no tumor cell staining), 1+ (< or =30%), 2+ (31% to 60%), 3+ (61% to 90%), and 4+ (>90%). The staining intensity of SCMs was scored as weak, moderate, or strong. We also compared them with currently used GCT markers placental-like alkaline phosphatase (PLAP), alpha-fetoprotein (AFP), c-KIT, CD30, and glypican-3. All 16 seminomas showed staining for SALL4 (4+ in 15, 2+ in 1) (15 strong, 1 moderate), OCT4 (4+ in 11, 3+ in 4, 2+ in 1) (13 strong, 3 moderate), and UTF1 (4+ in 13, 3+ in 2, 2+ in 1) (7 strong, 5 moderate, 4 weak). Positive staining was shown by 9/9 seminomas tested for NANOG (4+ in 7, 2+ in 2) (8 strong, 1 weak), TCL1 (4+ strong in all), c-KIT (4+ in all), and PLAP (4+ in 5, 3+ in 1, 2+ in 2, 1+ in 1), but SOX2 staining was negative in all these tumors. All 3 ECs showed 4+ strong staining for SALL4, OCT4, and UTF1 but negative for TCL1. SOX2 staining was seen in 3/3 ECs (4+ strong in 1, 3+ weak to moderate in 2) whereas NANOG staining was seen in 2/3 ECs (2+ weak, 1+ moderate). CD30 staining was seen in 3/3 ECs (1+, 2+, 4+). Strong SALL4 staining was seen in 10/10 YSTs (4+ in 9, 2+ in 1). All 10 YSTs showed AFP (1+ in 7, 2+ in 1, 3+ in 2) and glypican-3 (1+ in 3, 2+ in 1, 3+ in 5, 4+ in 1) staining but only 4/10 YSTs showed PLAP staining (1+ in all 4). The mean percentage of YST cells stained with SALL4 was 92%, whereas it was 23% for AFP, 50% for glypican-3, and 4% for PLAP (P<0.01). Focal (1+) SALL4 (weak) and SOX2 (weak to moderate) staining was seen in 2/7 and 4/7 teratomas, respectively. The choriocarcinoma was negative for all 6 SCMs. Eleven thymomas and 6 thymic carcinomas were negative for 6 SCMs. No staining of NANOG and SOX2 was seen in 20 lymphomas (5 Hodgkin, 5 large B cell, 5 lymphoblastic, 5 anaplastic large cell) (other 4 SCMs in lymphomas earlier studied). Our study indicates that SALL4, OCT4, NANOG, SOX2, UTF1, and TLC1 are novel sensitive diagnostic markers for primary mediastinal GCTs, with high specificity. Of these 6 SCMs, SALL4 is the only 1 expressed in YST. These novel SCMs are more sensitive than the currently used markers for mediastinal GCTs.

The prognosis and therapy for malignant ovarian germ cell tumors including embryonal carcinoma differ from those of other categories of ovarian tumors, making accurate diagnosis imperative for patient care. Because of its rarity, the protein markers and genomic alterations typifying primary ovarian embryonal carcinoma have not been fully characterized. The present study aims to establish a set of sensitive and specific protein markers useful for the diagnosis and delineation of ovarian embryonal carcinoma. Chromosomal 12p anomalies were analyzed by dual-color fluorescence in situ hybridization. In a series of 6 ovarian mixed germ cell tumors with a component of embryonal carcinomas, OCT4, CD30, SOX2, and glypican 3 expressions were analyzed immunohistochemically on formalin-fixed paraffin-embedded tissue specimens. The results were compared to 4 cases of mixed germ cell tumor that were originally mistaken for embryonal carcinoma. OCT4 marked the nuclei of 6 cases, among which 5 cases also showed glypican 3 expression indicative of an admixed yolk sac tumor component. SOX2 was positive in only 3 cases of embryonal carcinoma. In 1 case of mixed germ cell tumor containing embryonal carcinoma, embryoid bodies from a component of polyembryoma were demonstrated to be both OCT4 and CD30 positive. Two cases originally classified as embryonal carcinoma were OCT4 and CD30 negative and showed glypican 3 positivity. They were reclassified as solid variant of yolk sac tumor. Two other cases originally classified as embryonal carcinoma were OCT4 positive and CD30 negative and were classified as immature teratoma with neuroectodermal differentiation based on the immunohistochemical findings as well as morphologic features and were diagnosed as immature teratoma. Chromosome 12p alterations were identified in 5 of 6 cases of embryonal carcinomas. In summary, a panel of immunostains is more useful than a single biomarker in the differential diagnosis of ovarian germ cell tumors. Chromosome 12p fluorescence in situ hybridization combined with OCT4, CD30, and glypican 3 immunostains is useful in confirming the diagnosis of ovarian embryonal carcinoma.

Ovarian primitive germ cell tumors (GCTs) are uncommon tumors and sometimes pose diagnostic challenges. Among them, yolk sac tumor (YST) poses the greatest diagnostic difficulty and can be mistaken for clear cell carcinoma (CCC). Current immunohistochemical markers such as alpha-fetoprotein (AFP), glypican-3, cytokeratin (CK) 7, and epithelial membrane antigen (EMA) used to distinguish YST from CCC lack adequate sensitivity and specificity. Here by immunohistochemistry, we investigated a novel marker SALL4 in 98 GCTs (29 YSTs, 18 dysgerminomas, 6 gonadoblastomas, 6 embryonal carcinomas, 15 immature and 12 mature teratomas, 7 carcinoid tumors, 3 strumal carcinoids, and 2 struma ovarii) with particular interest of exploring SALL4 to distinguish YST from CCC. One hundred sixty-three non-GCTs including 45 CCCs were also stained. We found that SALL4 is strongly positive in more than 90% tumor cells in all YSTs, dysgerminomas, gonadoblastomas, and embryonal carcinomas. Variable SALL4 staining is seen in 11 of 15 immature teratomas. All other GCTs included in this study are negative for SALL4. Except 3 CCCs with focal SALL4 staining (<15% tumor cells), SALL4 is negative in the remaining 160 non-GCTs. We also compared SALL4 with AFP, glypican-3, CK7, and EMA in all YSTs and CCCs. AFP and glypican-3 are positive in 24 (83%) and 20 (69%) YSTs, respectively, whereas 16 (35%) and 13(28%) CCCs show positive AFP and glypican-3 staining, respectively. Three (10%) and 4 (14%) YSTs show focal (<2% tumor cells) CK7 and EMA staining, respectively. CK7 and EMA are positive in all 45 CCCs but 3 (7%) and 1 (2%) cases show staining in less than 30% tumor cells, respectively. Our findings indicate that SALL4 is a novel sensitive and specific marker for ovarian primitive GCTs. SALL4 is particularly useful in distinguishing YST from CCC and better than AFP, glypican-3, CK7, and EMA.

Octamer-4 (Oct4), a transcription factor involved in regulating human embryonic stem cells (ESCs), may play a role in tumorigenesis. Since little is known about the efficacy of Oct4 as a potential biomarker for gastric cancer (GC), we investigated its expression in GC tissues and its relationship to various clinicopathological parameters.

Primary tumor tissues and matching, adjacent non-cancerous tissues were obtained from 62 GC patients, and Oct4 expression was examined by reverse transcription-PCR (RT-PCR) and real-time PCR. Twenty biopsy specimens of atrophic gastritis and gastric ulcer individually were collected as control. To detect Oct4 expression in the paired GC and non-cancerous tissues at the protein level, Western blotting and immunohistochemistry (IHC) were employed. Correlation analyses were conducted to assess the relationship between Oct4 expression and clinicopathological parameters.

Oct4 expression levels were higher in GC tissues compared to matching, adjacent non-cancerous tissues, atrophic gastritis and gastric ulcer tissues. Additionally, Oct4 expression in GC tumors correlated with their differentiation status, but not with patient age or gender, tumor size, TNM stage, depth of invasion, or the presence of lymph node metastasis.

Oct4 may be a potential biomarker for the initiation, progression, and differentiation of human GC.

Primary testicular tumors are the most common causes of cancer in male dogs. Overall, the majority of canine patients should be cured by testicular surgery. However, tumor markers are not well-known in veterinary medicine. We sought to determine using immunohistochemistry whether the combined human testicular tumor markers (placental alkaline phosphatase, OCT3/4, CD30, alpha-fetoprotein, inhibin-alpha, vimentin, c-KIT, and desmin) are expressed in canine seminomas and Sertoli cell tumors (SCTs). We examined 35 canine testicular tumors, 20 seminomas and 15 SCTs. c-KIT was expressed markedly in canine seminomas. Both inhibin-alpha and vimentin were expressed significantly in canine SCTs. The results of this study demonstrate differences and similarities between tumor marker expression of testicular tumors in dogs and humans. All the main markers in current routine use are discussed as well as potential useful markers for benign and malignant tumors, and tumor progression.

Combined action of SOX and POU families of transcription factors plays major roles in embryonic development. In embryonic stem cells, the combination of SOX2 and POU5F1 (OCT3/4) is essential for maintaining the undifferentiated state by activating pluripotency-linked genes, and inhibition of genes involved in differentiation. Besides embryonic stem cells, POU5F1 is also present in early germ cells, primordial germ cells, and gonocytes, where it has a role in suppression of apoptosis. Here we demonstrate that SOX2 is absent in germ cells of human fetal gonads, and as expected carcinoma in situ (CIS), ie the precursor lesion of testicular germ cell tumours of adolescents and adults (TGCTs), and seminoma. Based on genome-wide expression profiling, SOX17 was found to be present, instead of SOX2, in early germ cells and their malignant counterparts, CIS and seminoma. Immunohistochemistry, western blot analysis, and quantitative RT-PCR showed that SOX17 is a suitable marker to distinguish seminoma from embryonal carcinoma, confirmed in representative cell lines. Aberrant SOX2 expression can be present in Sertoli cells when associated with CIS, which can be misdiagnosed as embryonal carcinoma. In conclusion, this study demonstrates the absence of SOX2 in human embryonic and malignant germ cells, which express SOX17 in conjunction with POU5F1. This finding has both diagnostic and developmental biological implications. It allows the identification of seminoma-like cells from embryonal carcinoma based on a positive marker and might be the explanation for the different function of POU5F1 in normal and malignant germ cells versus embryonic stem cells.

Clear cell adenocarcinoma in the urinary tract is a rare entity with an appearance resembling its counterpart in the female genital tract. Although several theories have been proposed about its origin, its exact histogenesis has remained uncertain.

We integrated molecular genetic evaluation by fluorescence in situ hybridization and X-chromosome inactivation with conventional morphologic and immunohistochemical analyses in 12 patients with clear cell adenocarcinomas in the urinary tract.

Concurrent urothelial carcinoma or urothelial carcinoma in situ was present in six cases (50%) and foci of cystitis glandularis were observed in four cases (33%). Neither intestinal metaplasia nor Müllerian component was identified in any case. Cytoplasmic expression of alpha-methylacyl-CoA racemase was demonstrable in 10 of 12 tumors (83%). Moderate to diffuse immunostaining for cytokeratin 7 was identified in all 12 tumors (100%), whereas only 3 of 12 (25%) tumors showed positive immunostaining for cytokeratin 20. Focal uroplakin III staining was seen in 6 of 12 tumors (50%). In five cases (42%), focal to moderate CD10 immunoreactivity was observed. Immunostains for OCT4 and CDX2 were completely negative in all tumors. In UroVysion fluorescence in situ hybridization assays, all tumors displayed chromosomal alterations similar to those commonly found in urothelial carcinoma. Identical patterns of nonrandom X-chromosome inactivation in concurrent clear cell adenocarcinoma and urothelial neoplasia were identified in two informative female cases.

Our findings support an urothelial origin for most clear cell adenocarcinomas of the urinary tract, despite their morphologic resemblance to certain Müllerian-derived tumors of the female genital tract.

It is becoming increasingly evident that cancer constitutes a group of diseases involving altered stem-cell maturation/differentiation and the disturbance of regenerative processes. The observed malignant transformation is merely a symptom of normal differentiation processes gone astray rather than the primary event. This review focuses on the role of cancer stem cells (CSCs) in three common but also relatively under-investigated cancers: head and neck, ovarian, and testicular cancer. For didactic purpose, the physiology of stem cells is first introduced using hematopoietic and mesenchymal stem cells as examples. This is followed by a discussion of the (possible) role of CSCs in head and neck, ovarian, and testicular cancer. Aside from basic information about the pathophysiology of these cancers, current research results focused on the discovery of molecular markers specific to these cancers are also discussed. The last part of the review is largely dedicated to signaling pathways active within various normal and CSC types (e.g. Nanog, Nestin, Notch1, Notch2, Oct3 and 4, Wnt). Different elements of these pathways are also discussed in the context of therapeutic opportunities for the development of targeted therapies aimed at CSCs. Finally, alternative targeted anticancer therapies arising from recently identified molecules with cancer-(semi-)selective capabilities (e.g. apoptin, Brevinin-2R) are considered.

Malignant ovarian germ cell tumors (MOGCTS) are rare but curable at all stages of disease. This review gives an outline of the management of this disease.

We performed a literature search in the PubMed of almost all relevant articles concerning MOGCTs on pathology, prognostic factors, surgery, post-operative therapy and late effects of therapy. The available literature is mainly composed of retrospective reviews and articles.

Prognostic factors include stage, amount of residual tumor, histologic type and raised tumor markers. For patients with early stage disease, cure rates approach 100%, while for those with advanced-stage disease are at least 75%. Appropriate surgical treatment for patients where fertility needs to be preserved consists in laparotomy with unilateral salpingo-oophorectomy (USO) and resection of all visible disease. For patients with advanced-stage disease, the role and the extent of debulking surgery remain controversial despite its routine use. However, it is suggested a benefit from minimal residual disease at completion of primary surgical cytoreduction with both non-platinum and platinum-based chemotherapy regimens. Second-look surgery clearly is not indicated in patients with early stage non-dysgerminoma or in all patients with dysgerminoma. However, teratoma patients may benefit from secondary cytoreduction. Three courses of bleomycin, etoposide and cisplatin (BEP) is the current standard adjuvant chemotherapy and four courses of BEP are recommended in case of bulky residual tumor after surgery. More evidence is required to show that surveillance is a safe option. There is a hint that high-dose chemotherapy may play a role in relapsed patients. The majority of MOGCTs patients who undergo fertility-sparing surgery and chemotherapy retain their gonadal and reproductive function. There is an increasing concern about life-threatening long-term effects of treatment.

MOGCTs are rare neoplasms that affect girls and young women and have excellent prognosis at all stages of disease with optimal therapy. The majority of MOGCTs patients retain their reproductive function.