The Evolution of Ovarian Carcinoma Subclassification

The phenotypically informed histotype classification remains the mainstay of ovarian carcinoma subclassification. Histotypes of ovarian epithelial neoplasms have evolved with each edition of the WHO Classification of Female Genital Tumours. The current fifth edition (2020) lists five principal histotypes: high-grade serous carcinoma (HGSC), low-grade serous carcinoma (LGSC), mucinous carcinoma (MC), endometrioid carcinoma (EC) and clear cell carcinoma (CCC). Since histotypes arise from different cells of origin, cell lineage-specific diagnostic immunohistochemical markers and histotype-specific oncogenic alterations can confirm the morphological diagnosis. A four-marker immunohistochemical panel (WT1/p53/napsin A/PR) can distinguish the five principal histotypes with high accuracy, and additional immunohistochemical markers can be used depending on the diagnostic considerations. Histotypes are further stratified into molecular subtypes and assessed with predictive biomarker tests. HGSCs have recently been subclassified based on mechanisms of chromosomal instability, mRNA expression profiles or individual candidate biomarkers. ECs are composed of the same molecular subtypes (POLE-mutated/mismatch repair-deficient/no specific molecular profile/p53-abnormal) with the same prognostic stratification as their endometrial counterparts. Although methylation analyses and gene expression and sequencing showed at least two clusters, the molecular subtypes of CCCs remain largely elusive to date. Mutational and immunohistochemical data on LGSC have suggested five molecular subtypes with prognostic differences. While our understanding of the molecular composition of ovarian carcinomas has significantly advanced and continues to evolve, the need for treatment options suitable for these alterations is becoming more obvious. Further preclinical studies using histotype-defined and molecular subtype-characterized model systems are needed to expand the therapeutic spectrum for women diagnosed with ovarian carcinomas.

BRCA1/2 NGS Somatic Testing in Clinical Practice: A Short Report

High-grade serous ovarian carcinoma (HGSOC) is the most common subtype of all ovarian carcinomas. HGSOC harboring BRCA1/2 germline or somatic mutations are sensitive to the poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi). Therefore, detecting these mutations is crucial to identifying patients for PARPi-targeted treatment. In the clinical setting, next generation sequencing (NGS) has proven to be a reliable diagnostic approach BRCA1/2 molecular evaluation. Here, we review the results of our BRCA1/2 NGS analysis obtained in a year and a half of diagnostic routine practice. BRCA1/2 molecular NGS records of HGSOC patients were retrieved from our institutional archive covering the period from January 2020 to September 2021. NGS analysis was performed on the Ion S5™ System (Thermo Fisher Scientific, Waltham, MA, USA) with the Oncomine™ BRCA Research Assay panel (Thermo Fisher Scientific). Variants were classified as pathogenic or likely pathogenic according to the guidelines of the American College of Medical Genetics and Genomics by using the inspection of Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) and ClinVar (NCBI) databases. Sixty-five HGSOC patient samples were successfully analyzed. Overall, 11 (16.9%) out of 65 cases harbored a pathogenic alteration in BRCA1/2, in particular, six BRCA1 and five BRCA2 pathogenic variations. This study confirms the efficiency and high sensitivity of NGS analysis in detecting BRCA1/2 germline or somatic variations in patients with HGSOC.

Current ideas about molecular genetic subtypes of ovarian cancer: a personalized approach and a new platform for further research

Highly malignant ovarian cancers are a histopathological diagnosis, but can be multiple diseases at the molecular level. Research aimed at identifying molecular genetic subtypes of ovarian cancer is being conducted to find an answer to the question: can different molecular subgroups influence the choice of treatment? One of the achievements of this direction is the recognition of the dualistic theory of the origin of ovarian carcinomas with their division into High-grade and Low-grade subtypes. However, the data of sequencing of the tumor genome suggest the existence of 6 subtypes of carcinoma, including two LG and four HG subtypes. Patients of subtype C1 are characterized by a high stromal response and have the lowest survival, tumors of C2 and C4 subtypes have a higher rate of intratumoral CD3 + cells, lower stroma gene expression and better survival than C1. The mesenchymal subtype C5 is widely represented by mesenchymal cells, characterized by overexpression of N-cadherins and P-cadherins, low expression of differentiation markers and lower survival than C2 and C4. The use of a consensus algorithm to determine the subtype allows the identification of only a minority of ovarian cancers (approximately 25%). In this regard, the practical significance of this classification still requires additional research, and today it is permissible to talk about the existence of only 2-3 reproducible subtypes. It is thought that it makes sense to randomize tumors into groups with altered expression of angiogenic genes and with overexpression of immune response genes, as in the angiogenic group there is a comparison of the advantage in survival (prescribing bevacizumab improves it, and in the immune group even increases bevacizumab). Molecular subtypes with poorer survival rates (proliferative and mesenchymal) also benefit most from bevacizumab treatment. The review focuses on some advances in understanding molecular, cellular, and genetic changes related to ovarian cancers with the results achieved so far in describing molecular subtypes of ovarian cancer. The available information is the basis for planning further research.

Combining ReACp53 with Carboplatin to Target High-Grade Serous Ovarian Cancers

Ovarian malignancies are a leading cause of cancer-related death for US women. High-grade serous ovarian carcinomas (HGSOCs), the most common ovarian cancer subtype, are aggressive tumors with poor outcomes. Mutations in TP53 are common in HGSOCs, with a subset resulting in p53 aggregation and misregulation. ReACp53 is a peptide designed to inhibit mutant p53 aggregation and has been shown efficacious in targeting cancer cells in vitro and in vivo. As p53 regulates apoptosis, combining ReACp53 with carboplatin represents a logical therapeutic strategy. The efficacy of this combinatorial approach was tested in eight ovarian cancer cell lines and 10 patient HGSOC samples using an in vitro organoid drug assay, with the SynergyFinder tool utilized for calculating drug interactions. Results demonstrate that the addition of ReACp53 to carboplatin enhanced tumor cell targeting in the majority of samples tested, with synergistic effects measured in 2 samples, additivity measured in 14 samples, and antagonism measured in 1 sample. This combination was found to be synergistic in OVCAR3 ovarian cancer cells in vitro through enhanced apoptosis, and survival of mice bearing OVCAR3 intraperitoneal xenografts was extended when treated with the addition of ReACp53 to carboplatin versus carboplatin alone. Results suggest that carboplatin and ReACp53 may be a potential strategy in targeting a subset of HGSOCs.

Immunohistochemical Evaluation of Adaptor Protein FAM159B Expression in Normal and Neoplastic Human Tissues

FAM159B is a so-called adaptor protein. These proteins are essential components in numerous cell signalling pathways. However, little is known regarding FAM159B expression in normal and neoplastic human tissues. The commercially available rabbit polyclonal anti-human FAM159B antibody HPA011778 was initially characterised for its specificity using Western blot analyses and immunocytochemistry and then applied to a large series of formalin-fixed, paraffin-embedded normal and neoplastic human tissue samples. Confirmation of FAM159B’s predicted size and antibody specificity was achieved in BON-1 cells, a neuroendocrine tumour cell line endogenously expressing FAM159B, using targeted siRNA. Immunocytochemical experiments additionally revealed cytoplasmic expression of the adaptor protein. Immunohistochemical staining detected FAM159B expression in neuronal and neuroendocrine tissues such as the cortex, the trigeminal ganglia, dorsal root and intestinal ganglia, the pancreatic islets and the neuroendocrine cells of the bronchopulmonary and gastrointestinal tract, but also in the syncytiotrophoblasts of the placenta. FAM159B was also expressed in many of the 28 tumour entities investigated, with high levels in medullary and anaplastic thyroid carcinomas, parathyroid adenomas, lung and ovarian carcinomas, lymphomas and neuroendocrine tumours of different origins. The antibody HPA011778 can act as a useful tool for basic research and identifying FAM159B expression in tissue samples.

CLINICAL AND EPIDEMIOLOGICAL FEATURES OF OVARIAN NEOPLASMS IN GRODNO REGION

Background. When providing specialized medical care and planning preventive measures, analysis of epidemiological data is instrumental in determining what should be done to reduce morbidity and mortality from ovarian malignant neoplasms (OMNs) within the given scenario. Purpose of research. To study the epidemiological situation with OMNs in the Grodno region. Material and methods. The OMN incidence and indicators of the quality of oncological care in the Grodno region were analyzed according to the data obtained from the Belarusian cancer registry. Results. Since 2007, the OMN morbidity and mortality rates have been relatively stable. In most cases, the diagnosis of malignant ovarian pathology has been based on the results of a pathomorphological investigation. The histological variant of the neoplasm significantly affects the prognosis for life. The most common neoplasms are serous ovarian carcinomas (69%). Neoplasms of non-epithelial origin occur in 8% of all cases. About 16% of women have multiple primary neoplasms with ovarian involvement. In most cases of metachronous development of polyneoplasia the ovarian neoplasm occurs last. The analysis of the age-specific morbidity showed that OMN was most often (52%) diagnosed at the age of 46-65 years. During the study period, about 70% of neoplasms were diagnosed at a later stage, 10% of patients were incurable and received only symptomatic therapy. The indicators of the quality of oncological care demonstrate an increase in the number of cases diagnosed at an early stage. In 2019, in the Grodno region, OMNs of stage I-II were diagnosed in 42% of patients. Conclusion. To improve oncological care for the population and reduce morbidity and mortality from OMNs, it is necessary to develop and implement a set of measures aimed primarily at early diagnosis of the disease and prevention of neoplasm development in the case of primary multiple forms.