Unclassified Variants of BRCA1 and BRCA2 in Korean Patients With Ovarian Cancer

Objective The aim of the present study was to investigate unclassified variants (UVs) in BRCA1 and 2 of Korean patients with ovarian cancer. Methods We retrospectively analyzed 138 patients diagnosed with ovarian/fallopian tubal/peritoneal cancer between January 2013 and January 2016, whose BRCA genetic test results and clinical characteristics were available for review. Patient peripheral blood lymphocyte specimens were assessed for BRCA mutations and variations by direct sequencing. Identified UVs were classified according to several algorithms. Results The results of genetic testing revealed 31 (22.5%, 31/138) pathogenic BRCA mutations (24 BRCA1 , 7 BRCA2 mutations). The BRCA1 c.390C>A mutation was observed in 4 patients (12.9%, 4/31). Thirty-four (24.6%, 34/138) BRCA UVs were identified in 33 patients. Of these, the BRCA1 c.4883T>C and BRCA2 c.8187G>T variants were each detected in 4 patients (4/34, 11.8%). According to the used algorithms and cosegregation test, the BRCA1 c.5339T>C and BRCA2 c.8437_8439delGGA variants were both predicted to be likely pathogenic. Conclusions The 2 identified likely pathogenic UVs require further verification with clinical evidence. Clarifying the clinical significance of UVs is an increasingly important step for cancer treatment in the current era of precision medicine.