Guidelines of the Brazilian Society of Surgical Oncology for anatomopathological, immunohistochemical, and molecular testing in female tumors.

INTRODUCTION: Precision medicine has revolutionized oncology, providing more personalized diagnosis, treatment, and monitoring for patients with cancer. In the context of female-specific tumors, such as breast, ovarian, endometrial, and cervical cancer, proper tissue collection and handling are essential for obtaining tissue, immunohistochemical (IHC), and molecular data to guide therapeutic decisions. OBJECTIVES: To establish guidelines for the collection and handling of tumor tissue, to enhance the quality of samples for histopathological, IHC, genomic, and molecular analyses. These guidelines are fundamental in informing therapeutic decisions in cancer treatment. METHOD: The guidelines were developed by a multidisciplinary panel of renowned specialists between June 12, 2013 and February 12, 2024. Initially, the panel deliberated on critical and controversial topics related to conducting precision medicine studies focusing on female tumors. Subsequently, 22 pivotal topics were identified within the framework and assigned to groups. These groups reviewed relevant literature and drafted preliminary recommendations. Following this, the recommendations were reviewed by the coordinators and received unanimous approval. Finally, the groups made the final adjustments, classified the level of evidence, and ranked the recommendations. CONCLUSION: The collection of surgical samples requires minimum quality standards to enable histopathological, IHC, genomic, and molecular analyses. These analyses provide crucial data for informing therapeutic decisions, significantly impacting potential survival gains for patients with female tumors.

Management of endometrial cancer in Latin America: raising the standard of care and optimizing outcomes.

Molecular characterization of endometrial cancer is allowing for increased understanding of the natural history of tumors and paving a more solid pathway for novel therapies. It is becoming increasingly apparent that molecular classification is superior to histological classification in terms of reproducibility and prognostic discrimination. In particular, the Proactive Molecular Risk Classifier for Endometrial Cancer allows classification of endometrial cancer into groups very close to those determined by the Cancer Genome Atlas Research Network-that is, DNA polymerase epsilon-mutated, mismatch repair-deficient, p53 abnormal, and non-specific molecular profile tumors. The transition from the chemotherapy era to the age of targeted agents and immunotherapy, which started later in endometrial cancer than in many other tumor types, requires widespread availability of specialized pathology and access to novel agents. Likewise, surgical expertise and state-of-the-art radiotherapy modalities are required to ensure adequate care. Nevertheless, Latin American countries still face considerable barriers to implementation of international guidelines. As we witness the dawn of precision medicine as applied to endometrial cancer, we must make continued efforts towards improving the quality of care in this region. The current article discusses some of these challenges and possible solutions.

Triple-negative breast cancer: from none to multiple therapeutic targets in two decades.

Triple-negative breast cancers (TNBCs) are more likely to occur in younger patients and have a poor prognosis. They are highly heterogeneous tumors consisting of different molecular subtypes. The only common characteristic among them is the absence of targets for endocrine therapy and human epidermal growth factor receptor 2 (HER2) blockade. In the past two decades, there has been an increased understanding of these tumors from a molecular perspective, leading to their stratification according to new therapeutic strategies. TNBC has ushered breast carcinomas into the era of immunotherapy. The higher frequency of germline BRCA mutations in these tumors enables targeting this repair defect by drugs like PARP inhibitors, resulting in synthetic lethality in neoplastic cells. Additionally, we have the identification of new molecules to which this generation of smart drugs, such as antibody-drug conjugates (ADCs), are directed. In this review, we will discuss the trajectory of this knowledge in a systematic manner, presenting the molecular bases, therapeutic possibilities, and biomarkers.

Clinicopathological characteristics of endometrial carcinomas according to DNA mismatch repair protein status.

DNA mismatch repair protein deficiency (MMRd) in endometrial carcinoma is associated with the risk of Lynch syndrome and response to immune checkpoint inhibitors. It is also related to microsatellite instability and corresponds to a molecular subtype of endometrial tumor with an unclear prognosis. Here, we evaluated the clinicopathological characteristics and prognosis of 312 consecutive endometrial carcinoma cases submitted to complete surgical staging at a single institution. We compared MMRd and mismatch repair protein-proficient (MMRp) tumors and examined the effects of the MMR protein loss type (MLH1/PMS2 vs. MSH2/MSH6) and influence of L1CAM and p53 expression. The median follow-up period was 54.5 (range, 0-120.5) months. No difference was observed between MMRd [n = 166 (37.2%)] and MMRp [n = 196 (62.8%)] cases in terms of age, body mass index, FIGO stage, tumor grade, tumor size, depth of myometrial infiltration, or lymph node metastasis. More MMRd than MMRp tumors had endometrioid histology (87.9% vs. 75.5%) and despite MMRd had more lymphovascular space invasion (LVSI; 27.2% vs. 16.9%), they presented fewer recurrences and no difference in lymph node metastasis and disease-related death. Relative to those with MLH1/MSH6 loss, tumors with MSH2/MSH6 loss were diagnosed at earlier FIGO stages, were smaller, and had less ≥50% myometrial invasion, LVSI and lymph node metastasis. Outcomes, however, did not differ between these groups. L1CAM positivity and mutation-type p53 expression were more common in MMRp than in MMRd tumors and did not differ between the MLH1/PMS2 and MSH2/MSH6 loss groups. In the entire cohort, L1CAM and mutation p53 expression were associated with worse prognosis, but only non-endometrioid histology, FIGO stage III/IV, and deep myometrial infiltration were significant predictors. In the subgroup of endometrioid carcinomas, only FIGO stage III/IV was associated with poor outcomes. The risk of lymph node metastasis was associated with tumor size, non-endometrioid histology, and multifocal LVSI. For MMRd tumors, only tumor size and myometrial invasion depth were predictive of lymph node involvement. In our cohort, MMRd tumors were associated with greater recurrence-free, but not overall, survival. The precise identification of MMRd status, present in a substantial proportion of endometrial cancer cases, is a challenge to be overcome for proper patient management. MMRd status serves as a marker for Lynch syndrome, and a significant number of these tumors are high risk and candidate to immunotherapy.

Mucinous Cystadenoma Arising in a Uterine Isthmocele: A Case Report.

Isthmocele is a discontinuation of the myometrium at the uterine scar site in a patient with a previous cesarian section (CS). The cause of isthmocele appears to be multifactorial. Poor surgical technique, low incision location, uterine retroflection, obesity, smoking, inadequate healing of scars, and maternal age are possible related factors. Most patients with this condition are asymptomatic. However, women can present with postmenstrual bleeding, pelvic pain, subfertility, dysmenorrhea, infertility, and scar abscess. Brazil has one of the world's highest cesarean section rates. One of the consequences of the rising rate of CS is the isthmocele, an emerging female health problem. Here we report a case of mucinous cystadenoma arising in a uterine isthmocele, a complication, as far as we could investigate, not yet described in the literature.

Istmocele é a descontinuidade do miométrio no local da cicatriz uterina em paciente com cesariana anterior. A causa da istmocele parece ser multifatorial. Má técnica cirúrgica, baixa localização da incisão, retroflexão uterina, obesidade, tabagismo, cicatrização inadequada de cicatrizes e idade materna são possíveis fatores relacionados. A maioria dos pacientes com esta condição é assintomática. No entanto, as mulheres podem apresentar sangramento pós-menstrual, dor pélvica, subfertilidade, dismenorreia, infertilidade e abscesso cicatricial. O Brasil tem uma das maiores taxas de cesariana do mundo. Uma das consequências da taxa crescente de cesarianas é a istmocele, um problema emergente de saúde feminina. Aqui relatamos um caso de cistoadenoma mucinoso originado em uma istmocele uterina, uma complicação ainda não descrita, até onde pudemos investigar.

Association Between GATA3 and Histopathological and Immunohistochemical Parameters in Early-Infiltrating Breast Carcinomas.

Objective: This study evaluated the frequency of GATA-binding protein 3 (GATA3) expression in early breast cancer and its relationship with histopathological and immunohistochemical parameters. Materials and Methods: GATA3 was analysed by immunohistochemistry in histological sections of tumors from 105 female patients, with histological diagnosis of invasive breast carcinoma (BC), at clinical stages I, II and IIIA, who underwent primary surgical treatment. GATA3 nuclear expression was determined as the percentage of positive tumor cells and further categorized as high (positive expression in more than 95% of cells) or non-high (negative or low positive expression in up to 95% of tumor cells). GATA3 expression was analysed according to the patient age, tumor and node pathological stage, histological type, histological and nuclear grade, lymphovascular invasion, and estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor 2 (HER2) status, and Ki-67 expression. Results: GATA3 expression was positive in 103 cases (98.1%). High expression was significantly associated with low histological and nuclear grade, positive hormonal receptors, and less proliferative activity based on Ki-67 expression. A prominent feature was that 94.7% of the ER-positive/HER2-negative cases presented high-GATA3 expression, as 94.0% of the tumors showing high-GATA3 were ER-positive. In ER-negative/HER2-positive or ER-negative/HER2- negative, high-GATA3 was present in 25% while 75% were non-high-GATA3 compared with ER-positive/HER2- negative (4.1%) and ER-positive/HER2-positive (20%). Proliferative activity in triple-negative breast cancer tended to be higher among tumors with low-GATA3, irrespective of AR expression. In the group of ER-positive/HER2-negative tumors only three cases were low-GATA3 (85% and 80%), both with high proliferative activity. Conclusion: High GATA3 expression is associated with favorable histopathologic and immunohistochemical BC prognostic factors.

Recommendations for the treatment of vulvar cancer in settings with limited resources: Report from the International Gynecological Cancer Society consensus meeting.

Introduction: Due to scant literature and the absence of high-level evidence, the treatment of vulvar cancer is even more challenging in countries facing limited resources, where direct application of international guidelines is difficult. Recommendations from a panel of experts convened to address some of these challenges were developed. Methods: The panel met in Rio de Janeiro in September 2019 during the International Gynecological Cancer Society congress and was composed of specialists from countries in Africa, Asia, Eastern Europe, Latin America, and the Middle East. The panel addressed 62 questions and provided recommendations for the management of early, locally advanced, recurrent, and/or metastatic vulvar cancer. Consensus was defined as at least 75% of the voting members selecting a particular recommendation, whereas a majority vote was considered when one option garnered between 50.0% and 74.9% of votes. Resource limitation was defined as any issues limiting access to qualified surgeons, contemporary imaging or radiation-oncology techniques, antineoplastic drugs, or funding for the provision of contemporary medical care. Results: Consensus was reached for nine of 62 (14.5%) questions presented to the panel, whereas a majority vote was reached for 29 (46.7%) additional questions. For the remaining questions, there was considerable heterogeneity in the recommendations. Conclusion: The development of guidelines focusing on areas of the world facing more severe resource limitations may improve medical practice and patient care.

Recommendations for the prevention, screening, diagnosis, staging, and management of cervical cancer in areas with limited resources: Report from the International Gynecological Cancer Society consensus meeting.

Introduction: Nearly 85% of cervical cancer new cases are diagnosed in limited resources countries. Although several strategies have been proposed to reduce the disease burden, challenges remain to provide the best possible care. We report recommendations from an expert consensus meeting convened to address from prevention to management of cervical cancer in limited resources countries. Methods: The expert panel, composed by invited specialists from 38 developing countries in Africa, Asia, Eastern Europe, Latin America, and the Middle East, convened in Rio de Janeiro in September 2019, during the Global Meeting of the International Gynecological Cancer Society (IGCS). Panel members considered the published scientific evidence and their practical experience on the topics, as well as the perceived cost-effectiveness of, and access to, the available interventions. The focus of the recommendations was on geographic regions rather than entire countries because medical practice varies considerably in the countries represented. Resource limitation was qualified as limited access to qualified surgeons, contemporary imaging or radiation-oncology techniques, antineoplastic drugs, or overall funding for provision of state-of-the-art care. Consensus was defined as at least 75% of the voting members selecting a particular answer of the multiple-choice questionnaire, whereas the majority vote was considered as 50% to 74.9%. Results: Consensus was reached for 25 of the 121 (20.7%) questions, whereas for 54 (44.6%) questions there was one option garnering between 50% to 74.9% of votes (majority votes). For the remaining questions, considerable heterogeneity in responses was observed. Discussion: The implementation of international guidelines is challenging in countries with resource limitations or unique health-care landscapes. The development of guidelines by the health care providers in those regions is more reflective of the reality on the ground and may improve medical practice and patient care. However, challenges remain toward achieving that goal at political, economic, social, and medical levels.

A novel WT1 heterozygous nonsense mutation (p.K248X) causing a mild and slightly progressive nephropathy in a 46,XY patient with Denys-Drash syndrome.

WT1 mutations have been described in a variety of syndromes, including Denys-Drash syndrome (DDS), which is characterized by predisposition to Wilms' tumor, genital abnormalities and development of early nephropathy. The most frequent WT1 defects in DDS are missense mutations located in exons 8-9. Our aim is to report a novel WT1 mutation in a 46,XY patient with a DDS variant, who presented a mild nephropathy with a late onset diagnosed during adolescence. He had ambiguous genitalia at birth. At 4 months of age he underwent nephrectomy (Wilms' tumor) followed by chemotherapy. Ambiguous genitalia were corrected and bilateral gonadectomy was performed. Sequencing of WT1 identified a novel heterozygous mutation (c.742A>T) in exon 4 that generates a premature stop codon (p.K248X). Interestingly, this patient has an unusual DDS nephropathy progression, which reinforces that patients carrying WT1 mutations should have the renal function carefully monitored due to the possibility of late-onset nephropathy.

Everolimus plus anastrozole for female adnexal tumor of probable Wolffian origin (FATWO) with STK11 mutation.

Female adnexal tumor of probable Wolffian origin (FATWO) are a rare type of cancer that originates from Wolffian duct remnants. Due to its rarity, no standard systemic treatment is established for cases of recurrent or metastatic disease. Previous literature reported the use of platinum-based chemotherapy and c-Kit tyrosine kinase inhibitors for FATWO cases with c-Kit positive expression. Currently, however, the broader availability of next-generation sequencing (NGS) tests allows a better molecular characterization of rare cancer such as FATWO and a possibility for the use of personalized, targeted therapy. Previous case series that performed NGS for FATWO patients described the presence of STK11 mutations in a considerable number of cases, representing a potential target in this population. To our knowledge, we describe here the first case report of a patient with FATWO and STK11 mutation exhibiting a considerable and durable response after treatment with an mTOR inhibitor plus endocrine therapy.

Accuracy of frozen section in intraoperative margin assessment for breast-conserving surgery: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: It is well established that tumor-free margin is an important factor for reducing local recurrence and reoperation rates. This systematic review with meta-analysis of frozen section intraoperative margin assessment aims to evaluate the accuracy, and reoperation and survival rates, and to establish its importance in breast-conserving surgery. METHODS: A thorough review was conducted in all online publication-databases for the related literature up to March 2020. MeSH terms used: "Breast Cancer", "Segmental Mastectomy" and "Frozen Section". We included the studies that evaluated accuracy of frozen section, reoperation and survival rates. To ensure quality of the included articles, the QUADAS-2 tool (adapted) was employed. The assessment of publication bias by graphical and statistical methods was performed using the funnel plot and the Egger's test. The review protocol was registered in PROSPERO (CRD42019125682). RESULTS: Nineteen studies were deemed suitable, with a total of 6,769 cases. The reoperation rate on average was 5.9%. Sensitivity was 0.81, with a Confidence Interval of 0.79-0.83, p = 0.0000, I2 = 95.1%, and specificity was 0.97, with a Confidence Interval of 0.97-0.98, p = 0.0000, I-2 = 90.8%, for 17 studies and 5,615 cases. Accuracy was 0.98. Twelve studies described local recurrence and the highest cumulative recurrence rate in 3 years was 7.5%. The quality of the included studies based on the QUADAS-2 tool showed a low risk of bias. There is no publication bias (p = 0.32) and the funnel plot showed symmetry. CONCLUSION: Frozen section is a reliable procedure with high accuracy, sensitivity and specificity in intraoperative margin assessment of breast-conserving surgery. Therefore, this modality of margin assessment could be useful in reducing reoperation rates.

Complete Clinical Response in Stage IVB Endometrioid Endometrial Carcinoma after First-Line Pembrolizumab Therapy: Report of a Case with Isolated Loss of PMS2 Protein.

Endometrial cancer is the only gynecological cancer that is rising in incidence and associated mortality worldwide. Although most cases are diagnosed as early stage disease, with chances of cure after primary surgical treatment, those with advanced or metastatic disease have a poor prognosis because of the quality of treatment options that are currently available. Mismatch repair (MMR)-deficient cancers are susceptible to programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 inhibitors. The US Food and Drug Administration granted accelerated approval to pembrolizumab for MMR-deficient tumors, the first tumor-agnostic approval for a drug. We present a case of stage IV endometrioid endometrial carcinoma with isolated PMS2 protein loss, in which treatment with first-line pembrolizumab therapy achieved a complete clinical and pathological response of tumor.

Nipple-sparing mastectomy for early breast cancer: the importance of intraoperative evaluation of retroareolar margins and intra-nipple duct removal.

BACKGROUND: Nipple-sparing mastectomy (NSM) is increasingly performed for breast cancer (BC) treatment. To ensure local control with this procedure, it is important to obtain clear surgical margins. Here, we aimed to estimate the confidence in intraoperative evaluation of the retroareolar margin (IERM) and the necessity of removing the intra-nipple ducts. METHODS: In this retrospective cohort study, we evaluated 224 BC (infiltrating carcinoma 178, ductal carcinoma in situ 46) patients, who underwent NSM. IERM was determined via cytology and frozen sections. Following gland removal, the intra-nipple ducts were excised and embedded in paraffin for analysis. The retroareolar tissue was also paraffin-embedded and reanalyzed for definitive evaluation of retroareolar margins (DERM). The IERM predictive capacity in relation to DERM and the frequency of intra-nipple duct involvement were estimated. RESULTS: IERM classified the sub-nipple areolar complex area as cancer-free in 219 cases (97.8%). The condition of clear retroareolar margin was confirmed by DERM in 216 cases (98.6%). The IERM accuracy was estimated as 98.6%. Ductal carcinoma in situ was detected in intra-nipple ducts using paraffin sections in 1.8% of the cases, despite clear IERM (4/219). CONCLUSIONS: In conclusion, IERM affords high accuracy and its results are suitable to manage the nipple-areolar complex. Nevertheless, some patients may retain residual disease in the intra-nipple ducts; thus, these ducts should ideally be removed during NSM.

L1 cell adhesion molecule (L1CAM) in stage IB cervical cancer: distinct expression in squamous cell carcinomas and adenocarcinomas.

AIMS: L1 cell adhesion molecule (L1CAM) has been shown to be correlated with tumour progression, attributed to its possible association with epithelial-mesenchymal transition (EMT), characterised by the expression of vimentin and loss of e-cadherin. Herein, we investigate the associations between L1CAM and clinicopathological parameters, as well as the expression of vimentin and e-cadherin, in carcinomas restricted to the cervix. METHODS: The study was retrospective observational and included 45 squamous cell carcinomas (63.4%) and 26 adenocarcinomas (36.6%) submitted to primary surgical treatment. Patient age, FIGO (International Federation of Gynecology and Obstetrics) stage, tumour size and follow-up were obtained from the medical records. All the slides were revised to evaluate histological differentiation, lymphovascular space invasion, depth of infiltration, disease-free cervical wall thickness, pattern of invasion front, Silva pattern (for adenocarcinomas) and the percentage of tumour-infiltrating lymphocytes. Tissue microarrays were constructed for immunohistochemical staining for L1CAM, e-cadherin and vimentin. RESULTS: Adenocarcinomas were associated with lower disease-free and overall survival. L1CAM and vimentin expressions were more frequent among adenocarcinomas, although loss of e-cadherin expression was more common among squamous carcinomas. L1CAM expression was associated with larger tumours, vimentin expression and lower disease-free survival. No association was observed between the expression of either L1CAM or vimentin and loss of e-cadherin. High levels of tumour-infiltrating lymphocytes were more frequent in squamous cell carcinoma, high-grade tumours, destructive pattern at front of invasion and loss of e-cadherin expression. CONCLUSIONS: Our results confirm the prognostic role of L1CAM in cervical carcinomas, but suggest a role for mechanisms other than EMT.

Ten years of experience with endometrial cancer treatment in a single Brazilian institution: Patient characteristics and outcomes.

Few reports have described the clinical and prognostic characteristics of endometrial cancer, which is increasing worldwide, in large patient series in Brazil. Our objective was to analyze the clinicopathological characteristics, prognostic factors, and outcomes of patients with endometrial cancer treated and followed at a tertiary Brazilian institution over a 10-year period.This retrospective study included 703 patients diagnosed with endometrial cancer who were treated at a public academic tertiary hospital between 2008 and 2018. The following parameters were analyzed: age at diagnosis, race, body mass index, serum CA125 level before treatment; histological type and grade, and surgical stage. Outcomes were reported relative to histological type, surgical staging, serum CA125, lymph-vascular space involvement (LVSI), and lymph-node metastasis. The median patient age at diagnosis was 63 (range, 27-93) years (6.4% were <50 years). Minimally invasive surgeries were performed in 523 patients (74.4%). Regarding histological grade, 468 patients (66.5%) had low-grade endometrioid histology and 449 patients (63.9%) had stage I tumors. Tumors exceeded 2.0 cm in 601 patients (85.5%). Lymphadenectomy was performed in 551 cases (78.4%). LVSI was present in 208 of the patients' tumors (29.5%). Ninety-three patients (13.2%) had recurrent tumors and 97 (13.7%) died from their malignant disease. The robust prognostic value of FIGO stage and lymph node status were confirmed. Other important survival predictors were histological grade and LVSI [overall survival: hazard ratio (HR) = 3.75, p < 0.001 and HR = 2.01, p = 0.001; recurrence: HR = 2.49, p = 0.004 and HR = 3.22, p = 0.001, respectively). Disease-free (p = 0.087) and overall survival (p = 0.368) did not differ significantly between patients with stage II and III disease. These results indicate that prognostic role of cervical involvement should be explored further. This study reports the characteristics and outcomes of endometrial cancer in a large population from a single institution, with systematic surgical staging, a predominance of minimally invasive procedures, and well-documented outcomes. Prognostic factors in the present study population were generally similar to those in other countries, though our patients' tumors were larger than in studies elsewhere due to later diagnosis. Our unexpected finding of similar prognoses of stage II and III patients raises questions about the prognostic value of cervical involvement and possible differences between carcinomas originating in the lower uterine segment versus those originating in the body and fundus. The present findings can be used to guide public policies aimed at improving the diagnosis and treatment of endometrial cancer in Brazil and other similar countries.

Aberrant Hypermetabolism of Benign Uterine Leiomyoma on 18F-FDG PET/CT.

Leiomyomas are prevalent benign smooth muscle tumors in the uterus, displaying variable degrees of FDG uptake on PET/CT. The glucose metabolism intensity of those lesions relies on biologic features and markedly increased FDG accumulation is more typically related to malignant diseases, as in the case of leiomyosarcomas. Notwithstanding that uterine fibroids typically exhibit mild to moderate FDG uptake, in this article we report a case of unexpectedly intense hypermetabolism of a benign uterine leiomyoma on a PET/CT scan performed for initial staging of a breast cancer patient.

Genetic Evidence of the Association of DEAH-Box Helicase 37 Defects With 46,XY Gonadal Dysgenesis Spectrum.

CONTEXT: 46,XY Gonadal dysgenesis (GD) is a heterogeneous group of disorders with a wide phenotypic spectrum, including embryonic testicular regression syndrome (ETRS). OBJECTIVE: To report a gene for 46,XY GD etiology, especially for ETRS. DESIGN: Screening of familial cases of 46,XY GD using whole-exome sequencing and sporadic cases by target gene-panel sequencing. SETTING: Tertiary Referral Center for differences/disorders of sex development (DSD). PATIENTS AND INTERVENTIONS: We selected 87 patients with 46,XY DSD (17 familial cases from 8 unrelated families and 70 sporadic cases); 55 patients had GD (among them, 10 patients from 5 families and 8 sporadic cases had ETRS), and 32 patients had 46,XY DSD of unknown etiology. RESULTS: We identified four heterozygous missense rare variants, classified as pathogenic or likely pathogenic in the Asp-Glu-Ala-His-box (DHX) helicase 37 (DHX37) gene in five families (n = 11 patients) and in six sporadic cases. Two variants were recurrent: p.Arg308Gln (in two families and in three sporadic cases) and p.Arg674Trp (in two families and in two sporadic cases). The variants were specifically associated with ETRS (7/14 index cases; 50%). The frequency of rare, predicted-to-be-deleterious DHX37 variants in this cohort (14%) is significantly higher than that observed in the Genome Aggregation Database (0.4%; P < 0.001). Immunohistochemistry analysis in human testis showed that DHX37 is mainly expressed in germ cells at different stages of testis maturation, in Leydig cells, and rarely in Sertoli cells. CONCLUSION: This strong genetic evidence identifies DHX37 as a player in the complex cascade of male gonadal differentiation and maintenance.