Tumour Versus Germline BRCA Testing in Ovarian Cancer: A Single-Site Institution Experience in the United Kingdom

Genomic and Molecular Characteristics of Ovarian Carcinosarcoma

Ovarian carcinosarcoma (OCS) is a rare malignancy with a poor prognosis. It is a biphasic tumor with malignant epithelial and mesenchymal components. A few mutations commonly seen in cancer have been identified in OCS, including TP53, PIK3CA, c-myc, ZNF217, ARID1A, and CTNNB1. Some OCS tumors have shown vascular endothelial growth factor positivity and limited HER2 expression. There is evidence of homologous recombination deficiency in OCS. This malignancy can be categorized as copy number high but has not been shown to have a high tumor mutational burden. There are mixed findings regarding the presence of biomarkers targeted by immune checkpoint inhibitors in OCS. For treatments other than systemic chemotherapy, the data available are largely based on in vitro and in vivo studies. In addition, there are case reports citing the use of poly-ADP ribose polymerase inhibitors, vascular endothelial growth factor inhibitors, and immunotherapy with varying degrees of success. This review paper will discuss the molecular and genomic characteristics of OCS, which can guide future treatment strategies.

Tumor BRCA Testing in Epithelial Ovarian Cancers: Past and Future-Five-Years' Single-Institution Experience of 762 Consecutive Patients

Simple Summary

Tumor BRCA testing is crucial in the clinical management of women affected by epithelial ovarian cancer (EOC). In the present study, we aimed to report the results of five years of experience in tumor BRCA testing performed in a single-institution diagnostic setting. We profiled 762 consecutive EOC patients with a failure rate of less than 1% and less than two weeks of turnaround time, which is consistent with the clinical needs. We identified 23.4% of cases with pathogenic/likely pathogenic mutations, including 76% of patients affected by germline and 24% by somatic alterations. Here, we proposed a comprehensive and multidisciplinary clinical workflow that could be successfully followed for the identification of somatic as well as germline alterations, maximizing the benefit of BRCA testing both from a therapeutic and risk assessment perspective.

Abstract

The establishment of PARP inhibitors in the treatment of epithelial ovarian carcinoma (EOC) has prompt BRCA assessment at the time of diagnosis. We described our five years of experience of tumor BRCA testing, as part of a multidisciplinary workflow for the management of EOC patients. We used a BRCA next-generation sequencing (NGS) test for profiling formalin-fixed, paraffin-embedded (FFPE) EOCs of 762 consecutive patients, with a success rate of 99.7% and a median turnaround time of 12 days. We found 178 (23.4%) cases with pathogenic/likely pathogenic (P/LP) mutations, 74 (9.7%) cases with variants of uncertain significance and 508 (66.8%) wild type tumors. Among 174 patients without P/LP mutations and investigated with multiple-ligation probe-amplification analysis on peripheral blood, two (1.1%) were positive for large rearrangements. Patients with P/LP alterations and/or with positive family history were referred to genetic counselling. Comparing tumor and blood NGS test results of 256 patients, we obtained a tumor test negative predictive value of 100% and we defined 76% of P/LP alterations as germline and 24% as somatic variants. The proposed workflow may successfully identify EOC patients with BRCA1/2 alteration, guiding both therapeutic and risk assessment clinical decisions.