The relationship between BRCA-associated breast cancer and age factors: an analysis of the Japanese HBOC consortium database

BRCA1/2 pathogenic variant prevalence in Japanese breast cancer is unclear. Here, we analyzedBRCA1/2 pathogenic variant prevalence with a particular focus on age factors, using the Japanese HBOC consortium database. All registered subjects were Japanese individuals who underwentBRCA1/2 genetic testing from January 1996 to July 2017 according to the Japanese HBOC consortium database. Cases were extracted and analyzed for each evaluation item. Overall BRCA1 and BRCA2 pathogenic variant prevalence was 11.2% and 9.0% in the cohort of 2366 proband patients, respectively. The age at onset of breast cancer for patients with BRCA1/2 pathogenic variants was significantly lower than that for patients without aBRCA1/2 pathogenic variant. In bothBRCA1/2patients, ages at onset were not statistically significantly different between two subtype groups (ER-positive vs. TNBC). We analyzed the BRCA1/2 pathogenic variant prevalence among age groups in patients with no family history of breast or ovarian cancer. In the TNBC group, the rate of genetic variants was more frequent among younger patients. Our results demonstrated that early breast cancer onset is associated with aBRCA1/2 pathogenic variant in the Japanese population. Younger TNBC patients were more likely to have aBRCA1/2 pathogenic variant irrespective of a family history of breast or ovarian cancer.

Automated summary

The prevalence of BRCA1/2 pathogenic variants in Japanese breast cancer patients is 11.2% and 9.0%, with early onset breast cancer associated with BRCA1/2 pathogenic variants. Younger TNBC patients are more likely to have BRCA1/2 pathogenic variants, regardless of family history of breast or ovarian cancer.