Recently characterized molecular events in uncommon gynaecological neoplasms and their clinical importance

Pediatric Sertoli-Leydig Cell Tumors of the Ovary: An Integrated Study of Clinicopathological Features, Pan-cancer-Targeted Next-generation Sequencing and Chromosomal Microarray Analysis From a Single Institution

Sertoli-Leydig cell tumors (SLCTs) are currently classified into 3 molecular subtypes: DICER1 -mutant (younger patient age), FOXL2 -mutant, and DICER1/FOXL2 -wildtype. However, it is not clear whether all pediatric SLCTs are DICER1 -mutant molecular subtypes and whether other molecular genetic aberrations besides DICER1 are involved in the pathogenesis and prognosis of these tumors. We studied comprehensive data for 8 cases of pediatric SLCTs, including clinicopathological features, pan-cancer-targeted next-generation sequencing/OncoKids panel, and chromosomal microarray analysis, to further analyze the correlation among clinicopathological features, molecular genetic aberrations, and prognosis. The ages of the patients ranged from 4 to 16 years (median, 14 y). Seven cases were moderately differentiated, and one was poorly differentiated with heterologous mesenchymal elements. Two cases had heterologous epithelium or retiform elements. Follow-up was available for all 8 patients (median, 49.5 mo). Seven patients were alive without evidence of recurrence or metastasis, and only case 5 developed metastases (synchronous bilateral pulmonary tumors with rhabdomyosarcomatous differentiation). All 8 tumors were found to harbor somatic hotspot DICER1 mutations, and 5 patients carried germline DICER1 mutations (2 of them had the phenotype of DICER1 syndrome). Together with recent studies, the DICER1 mutation frequency is 100% in pediatric SLCTs (n=27, age≤16 y). Copy number alterations were detected in 3 tumors; the only recurrent copy number alterations was the gain of whole chromosome 6 in case 5 and case 8. This is the first report describing clinicopathological features and molecular alterations in pediatric SLCTs. Our results demonstrate that all pediatric SLCTs belong to the DICER1 -mutant molecular subtype, highlighting that somatic hotspot DICER1 mutation detection has high sensitivity (100%) for the auxiliary diagnosis of pediatric SLCTs (age ≤16 y). Some pediatric SLCTs harbor molecular genetic aberrations other than DICER1 mutation, and their significance needs further study.

Unusual Aspects of Small Cell Carcinoma of the Ovary of Hypercalcaemic Type: Retained SMARCA4 Immunohistochemical Staining and Positive Staining With TLE1

Small cell carcinoma of the ovary of hypercalcaemic type (SCCOHT) is a rare and aggressive ovarian neoplasm that is most common in the second and third decades. Molecular studies have established inactivating SMARCA4 alterations as the driver of SCCOHT, these being present in over 95% of these neoplasms. SMARCA4 alterations almost always result in loss of immunoreactivity with SMARCA4 (BRG1) antibody, and this is an extremely useful adjunct in the diagnosis of SCCOHT. Herein, we report 7 cases of SCCOHT (2 from the same patient) with retention of nuclear immunoreactivity with SMARCA4, but with SMARCA4 alterations identified on molecular testing. All cases exhibited loss of SMARCA2 (BRM) immunoreactivity. In addition, following the identification of diffuse TLE1 immunoreactivity in one of these cases (which did not exhibit an SS18 gene rearrangement characteristic of synovial sarcoma), we stained a total of 63 cases of SCCOHT (14 on whole tissue sections: 49 on tissue microarray) with this marker and 7 of 14 (50%) and 22 of 49 (45%) were positive on whole sections and tissue microarray, respectively. Most cases were focally positive but occasional cases exhibited diffuse immunoreactivity. Our observations highlight the importance of SMARCA2 immunohistochemical staining and molecular testing in suspected cases of SCCOHT that exhibit retained SMARCA4 immunoreactivity. Th common expression of TLE1 in these neoplasms represents a potential diagnostic pitfall since synovial sarcoma may be considered in the differential, especially in cases with retained SMARCA4 immunohistochemistry.

Borderline With Bad Behavior: An Unusual Low-grade Serous Carcinoma With Dedifferentiation From a Serous Borderline Tumor

The pathogenesis of serous ovarian tumors has been extensively investigated, with a dualistic model dividing these cancers into 2 groups. Type I tumors, including low-grade serous carcinoma, is characteristic for concurrent presence of borderline tumors, less atypical cytology, relatively indolent biologic behavior, and molecular aberrations related to the MAPK pathway with chromosomal stability. Meanwhile, type II tumors, such as high-grade serous carcinoma, are notable for no significant association with borderline tumors, higher grade cytology, more aggressive biologic behavior, and TP53 mutations along with chromosomal instability. We describe a case of morphologic low-grade serous carcinoma with focally increased cytologic atypia arising in serous borderline tumors involving both ovaries, which demonstrated highly aggressive behavior despite several years of surgical and chemotherapeutic management. Each recurrent specimen contained more uniform higher grade morphology than what was seen in the original specimen. Immunohistochemical and molecular studies in both the original tumor and the most recent recurrence demonstrate identical mutations in the MAPK genes, but with additional mutations in the latter, notably an acquisition of a variant of possible clinical significance in the SMARCA4 gene, which is associated with dedifferentiation and aggressive biologic behavior. This case challenges our current and still evolving understanding of the pathogenesis, biologic behavior, and expected clinical outcome of low-grade serous ovarian carcinomas. It also underscores the need for further investigation into this complicated tumor.

Key changes to the world health organisation (who) classification of female genital tumours introduced in the 5TH edition (2020)

An updated World Health Organisation (WHO) Classification of Female Genital Tumours was published in Autumn 2020. We discuss the major new additions and changes from the prior 2014 Classification with discussion of the reasons underlying these. A feature of the new Classification is the greater emphasis on key molecular events with integration of morphological and-molecular features. Most of the major changes from the prior Classification pertain to uterine (corpus and cervix) and vulval tumours but changes in all organs are covered.

Progress in the pathological arena of gynecological cancers

This review covers the significant new developments in the pathological classification of gynecological tumors. Many of these were included in the updated World Health Organization Classification of Female Genital Tract Tumours, published in 2020. Topics include the compelling evidence that a large majority of extrauterine high‐grade serous carcinomas arise from the fallopian tube; the Cancer Genome Atlas (TCGA) Classification of endometrial carcinomas; the discovery that most so‐called synchronous endometrial and ovarian endometrioid carcinomas represent metastasis from the endometrium to the ovary; and the division of cervical, vaginal, and vulval carcinomas into clinically meaningful HPV‐associated and HPV‐independent types. Newly described tumor types are covered, including endometrial and ovarian mesonephric‐like adenocarcinoma, uterine sarcoma types associated with specific molecular abnormalities, and gastric (gastrointestinal)‐type adenocarcinomas of the endometrium and vagina. Important molecular events in ovarian sex cord–stromal tumors are also discussed.

Review of significant new developments in the classification of gynecological tumors; many are included in the 2020 World Health Organization Classification of Female Genital Tract Tumours.

Somatic tumour testing establishes that bilateral DICER1-associated ovarian Sertoli-Leydig cell tumours represent independent primary neoplasms

AIMS

Sertoli-Leydig cell tumours (SLCTs) are rare ovarian neoplasms that are commonly associated with somatic or germline DICER1 mutations, especially when of the moderately or poorly differentiated type. A large majority are unilateral, but bilateral neoplasms have been reported, sometimes in the context of germline DICER1 mutations (DICER1 syndrome). It is currently unknown whether these represent independent neoplasms or metastasis from one ovary to the other and we aimed to elucidate this.

METHODS AND RESULTS

We report three cases of bilateral ovarian SLCT (all in patients with DICER1 syndrome) and review all reported cases of bilateral neoplasms. In the three cases (all moderately or poorly differentiated neoplasms), the time interval between the discovery of the tumours in each ovary ranged from 2.7 years to 6 years. In all cases, different DICER1 somatic hotspot mutations within the two tumours provided definitive proof that they represent independent neoplasms; this may be important clinically. Our literature review revealed that, when this information was available, all patients with bilateral SLCT had a germline DICER1 mutation.

CONCLUSIONS

Bilateral ovarian SLCTs represent independent rather than metastatic neoplasms, and essentially always occur in the context of DICER1 syndrome.

CDK4/6 inhibitors target SMARCA4-determined cyclin D1 deficiency in hypercalcemic small cell carcinoma of the ovary

Inactivating mutations in SMARCA4 (BRG1), a key SWI/SNF chromatin remodelling gene, underlie small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). To reveal its druggable vulnerabilities, we perform kinase-focused RNAi screens and uncover that SMARCA4-deficient SCCOHT cells are highly sensitive to the inhibition of cyclin-dependent kinase 4/6 (CDK4/6). SMARCA4 loss causes profound downregulation of cyclin D1, which limits CDK4/6 kinase activity in SCCOHT cells and leads to in vitro and in vivo susceptibility to CDK4/6 inhibitors. SCCOHT patient tumors are deficient in cyclin D1 yet retain the retinoblastoma-proficient/p16INK4a-deficient profile associated with positive responses to CDK4/6 inhibitors. Thus, our findings indicate that CDK4/6 inhibitors, approved for a breast cancer subtype addicted to CDK4/6 activation, could be repurposed to treat SCCOHT. Moreover, our study suggests a novel paradigm whereby critically low oncogene levels, caused by loss of a driver tumor suppressor, may also be exploited therapeutically.

Second primary rhabdomyosarcoma of the uterine cervix presenting with synchronous ovarian Sertoli-Leydig cell tumor: An illustrative case of DICER1 syndrome

•Embryonal rhabdomyosarcoma of the uterine cervix and ovarian Sertoli-Leydig cell tumors are associated with DICER1 mutation•DICER1-associated tumors should prompt genetic counseling and testing•Somatic and germline genetic mutation profiles can be used to differentiate second primary from recurrent tumors.

Paediatric ovarian tumours and their associated cancer susceptibility syndromes

Non-epithelial ovarian tumours are rare neoplasms that occasionally arise in childhood and adolescence. They can be associated with various cancer susceptibility syndromes. The morphological overlap seen across these tumours and their rarity can make the diagnosis challenging. In the case of an incorrect diagnosis, the underlying genetic susceptibility may be missed. In this review, we outline the genetic background of ovarian non-epithelial tumours arising in children, emphasizing the genes harbouring pathogenic germline variants associated with each tumour type. Specifically, juvenile granulosa cell tumours, Sertoli-Leydig cell tumours, sex cord tumours with annular tubules, Sertoli cell tumours, germ cell tumours and small cell carcinoma of the ovary of hypercalcaemic type are discussed in this review. For each tumour type, we detail the personal and family history features and the presenting characteristics of the ovarian tumour as well as the pathological features and molecular markers that point towards a cancer predisposition syndrome. Throughout, we stress the need for specialised pathological review in difficult cases.

Tumor Microenvironment and Models of Ovarian Cancer: The 11th Biennial Rivkin Center Ovarian Cancer Research Symposium

OBJECTIVE

The aim of this study was to review the latest research advances on the topics of the ovarian cancer tumor microenvironment and models of ovarian cancer.

METHODS

In September 2016, a symposium of the leaders in the field of ovarian cancer research was convened to present and discuss current advances and future directions in ovarian cancer research.

RESULTS

One session was dedicated to Tumor Microenvironment and Models of Ovarian Cancer, and included a keynote presentation from Anil Sood, MD, and an invited oral presentation from David Huntsman, MD. Eight additional oral presentations were selected from abstract submissions. Twenty-nine abstracts were presented in poster format and can be grouped into the categories of stromal cells in the microenvironment, immune cells in the microenvironment, epithelial-mesenchymal transition and metastasis, metabolomics, and model systems including spheroids, murine models, and other animal models.

CONCLUSIONS

Rapid advances continue in our understanding of the influence of the tumor microenvironment on ovarian cancer progression and metastasis. Vascular endothelial cells, stromal cells, and immune cells all modulate epithelial tumor cell biology and therefore serve as potential targets for improved treatment responses either in conjunction with or instead of current treatment modalities. Characterization of the underlying genetic alterations in both the tumor cells and surrounding microenvironment cells enhances our understanding of tumor biology. Model systems including both in vitro and in vivo approaches allow novel advances. Technological advances including sequencing strategies, use of mass spectrometry for metabolomics and other studies, and bioengineering approaches all complement conventional methodologies to push forward our understanding and ultimately the treatment of ovarian cancer.

Ovarian sex-cord stromal tumours and small cell tumours: Pathological, genetic and management aspects

Non-epithelial ovarian cancers (NEOC) constitute a group of uncommon malignancies and their treatment is still a challenging task. Collectively, these tumours account for about 10% of all ovarian cancers and occur in all age groups from childhood to old-age. They include malignancies of germ cell origin, sex cord-stromal cell origin, and a variety of extremely rare ovarian cancers, such as small-cell carcinomas and sarcomas. Each of these classifications encompasses multiple histologic subtypes. It is imperative that these rare tumours are managed with accurate diagnosis, staging, and treatment, to optimise the outcome. The aetiology and molecular origins of each sub-group of NEOC remain largely unresolved, and international cooperation to promote high quality translational research is crucial. Much effort has been made into researching the molecular mechanisms underlying epithelial ovarian cancers, but far less is known about the genetic changes in NEOC. In this article, it is provided an overview of the current knowledge on the incidence, clinical presentation, pathology, genetics, therapeutic interventions, survival and prognostic factors of adult and juvenile granulosa cell tumours (GrCT), Sertoli-Leydig Cell tumours (SLCT) and small cell carcinoma of the ovary. We also consider future potential therapeutic targets in these rare cancers.

DICER1-related Sertoli-Leydig cell tumor and gynandroblastoma: Clinical and genetic findings from the International Ovarian and Testicular Stromal Tumor Registry

BACKGROUND

Ovarian sex cord-stromal tumors (OSCST) include juvenile granulosa cell tumors (JGCT), Sertoli-Leydig cell tumor (SLCT) and gynandroblastoma (GAB) among others. These ovarian sex cord-stromal tumors as well as other tumors including pleuropulmonary blastoma (PPB) may be associated with DICER1 mutations. We sought to describe the clinical and genetic findings from the first 107 individuals enrolled in the International Ovarian and Testicular Stromal Tumor Registry.

METHODS

Medical and family history were obtained for individuals consecutively enrolled in the International Ovarian and Testicular Stromal Tumor Registry. Pathology was centrally reviewed. DICER1 sequencing was performed on blood and tumor tissue.

RESULTS

Of the 107 participants, 49 had SLCT, 25 had JGCT and 5 had GAB. Nearly all (36/37) SLCTs and 4/4 GAB tested had a DICER1 mutation in an RNase IIIb domain hotspot; approximately half of these individuals had a predisposing germline DICER1 mutation. Metachronous SLCTs were seen in 3 individuals with germline DICER1 mutations. Other DICER1-associated conditions were seen in 19% of patients with SLCT or GAB. Three children of women with SLCT were diagnosed with PPB based on genetic testing and clinical screening during the course of this study. All were diagnosed with PPB in its earliest and most curable form (Type I), were treated with surgery alone, and are alive without evidence of disease.

CONCLUSIONS

Recognition of the distinct genetic basis for a group of these tumors improves precise classification in difficult cases and promotes mutation-based screening and early detection.

Genomic profiling of gynecologic cancers and implications for clinical practice

PURPOSE OF REVIEW

This article summarizes advances in the application of next-generation sequencing (NGS) to the personalized treatment of gynecologic malignancies.

RECENT FINDINGS

Many recurrent genomic alterations (GA) in gynecologic malignancies have been identified by studies applying NGS to tumor tissue, which can provide insights into tumor biology, diagnostic or prognostic information, and potential targeted therapy options. NGS can be used to assay single genes, portions of multiple genes ("hot-spot" panels), or the complete coding sequence of a broad range of cancer-associated genes [i.e. comprehensive genomic profiling (CGP)]. CGP of a patient's tumor reveals to practitioners clinically relevant GA (CRGA) and associated biomarker-matched treatments, with a goal of improving therapeutic response while limiting cumulative chemotherapeutic toxicities. Although the use of precision medicine for gynecologic cancers holds much promise, the data detailing impact on survival and quality of life is still accumulating, lagging behind other areas of oncology. Enrolling gynecologic oncology patients in genotype-matched trials remains challenging and highlights the need for more molecular-based basket trials for reproductive tract malignancies.

SUMMARY

Identification of molecular subsets with distinct clinical attributes, prognostic significance, and targeted therapy directed options is now feasible in clinical gynecologic oncology practice.