Somatic mutations in BRCA1&2 in 201 unselected ovarian carcinoma samples – single institution study

Ovarian cancer (OC) is the most lethal among gynecologic malignancies worldwide. Unfortunately, in around 70% of cases cancer is diagnosed in late stages (III-IV) which decreases the 5-year survival rate to 25%. The standard of care in ovarian cancer is debulking surgery followed by chemotherapy regimens based on platinum salts. Since 2014 PARP inhibitors became available for OC patients with germline or/and somatic mutations in BRCA1/2, including maintenance therapy. BRCA1/2 Next Generation Sequencing (NGS)-based analysis of formalin-fixed paraffin-embedded (FFPE) ovarian cancer samples becomes the standard of care. The aim of the present study was to evaluate the frequency of mutations in 201 unselected ovarian cancer tissues using the NGS method. In total, pathogenic mutations in both genes were detected in 24% (49/201) of the ovarian cancer cases tested. For 41 patients the results of testing of DNA isolated from blood sample revealed that 17% (35/201) mutations were germline origin, whereas 3% (6/201) mutations were somatic. In 4% (8/201) cases blood sample was inaccessible. The presence of pathogenic mutations was correlated with younger age at diagnosis and serous subtype. Close cooperation between many specialists (gynecologist, pathologist, oncologist, clinical genetics and molecular biologist) is indispensable for efficient and on-time BRCA1/2 ovarian tumor tissue testing.