Prevalence of and mutations in Japanese patients with triple-negative breast cancer: A single institute retrospective study.

Numerous databases for risk assessment of gene mutations contain insufficient data about Asians. Furthermore, few studies have reported the prevalence of germline mutations in Japanese patients, particularly those with triple-negative breast cancer (TNBC). The present study was a retrospective analysis of data from patients with TNBC who underwent mutation testing at Osaka International Cancer Institute (Osaka, Japan) between October 2014 and March 2020. A total of 65 patients with TNBC underwent a test for mutations, and 13 (20.0%) had deleterious mutations in the or genes. Furthermore, 12 out of 29 patients with a family history of breast or ovarian cancer had deleterious mutations, and only 1 of 34 without a family history had a mutation (41.4 vs. 2.9%; P=0.014). No patients aged >60 years had mutations; however, the age of diagnosis was not a significant risk factor for mutations (P=0.60). The prevalence of mutations in the present cohort of Japanese patients with TNBC was slightly higher than those reported in other larger studies from Europe and North America. Further data from large prospective studies are required to more precisely define the prevalence of mutations.