Breast and Ovarian Cancer Risks Due to Inherited Mutations in <i>BRCA1</i> and <i>BRCA2</i>

TLDR

Breast and ovarian cancer risks were assessed in Ashkenazi Jewish women carrying BRCA1 or BRCA2 mutations. The study examined 1,008 index cases and performed comprehensive molecular analysis of their families. Lifetime breast cancer risk for carriers was 82%, rising from 24% before 1940 to 67% after 1940, while ovarian cancer risk was 54% for BRCA1 and 23% for BRCA2 carriers; adolescent physical activity and lower obesity were linked to delayed breast cancer onset.

Abstract

Risks of breast and ovarian cancer were determined for Ashkenazi Jewish women with inherited mutations in the tumor suppressor genes BRCA1 and BRCA2 . We selected 1008 index cases, regardless of family history of cancer, and carried out molecular analysis across entire families. The lifetime risk of breast cancer among female mutation carriers was 82%, similar to risks in families with many cases. Risks appear to be increasing with time: Breast cancer risk by age 50 among mutation carriers born before 1940 was 24%, but among those born after 1940 it was 67%. Lifetime risks of ovarian cancer were 54% for BRCA1 and 23% for BRCA2 mutation carriers. Physical exercise and lack of obesity in adolescence were associated with significantly delayed breast cancer onset.