BRCA1 and BRCA2 mutations in Japanese patients with ovarian, fallopian tube, and primary peritoneal cancer

abstract

BACKGROUND

The contribution of BRCA1 and BRCA2 to ovarian cancer in Japanese patients is still unclear. This study investigated the frequency of germline mutations in BRCA1/2 in Japanese patients with ovarian, peritoneal, or fallopian tube cancer, regardless of their family histories, which were suggestive of hereditary breast and ovarian cancer.

METHODS

Ninety-five unselected women with ovarian cancer who were seen from 2013 to 2015 at Yamanashi Prefectural Central Hospital were enrolled. Analyses of BRCA1/2 gene mutations were performed with next-generation sequencing.

RESULTS

Twelve of the 95 patients (12.6%), including 5 in the BRCA1 (5.3%) and 7 in the BRCA2 (7.4%), had deleterious mutations. Among the 36 cases with a family history, 6 (16.7%) were found to carry mutations in BRCA1 and BRCA2. Notably, 6 of the 59 cases (10.2%) without a family history also had BRCA1/2 germline mutations. There was no statistical difference between the 2 groups (P = .36). The presence of mutations and their clinical relevance were studied. Mutation carriers were diagnosed at advanced stages (100% of positive cases among stage III or IV cases) and had poor prognostic histological subtypes (100% of positive cases had high-grade serous adenocarcinomas).

CONCLUSIONS

In this unselected Japanese population, approximately 13% of the cases with ovarian cancer appeared to be associated with an inherited risk, regardless of a family history. This finding indicates that BRCA1/2 genetic testing should be performed for all patients with ovarian cancers.