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 …

… To identify the risk of developing breast and ovarian cancer in Ashkenazi Jewish women
with inherited mutations in BRCA1 or BRCA2. … This article evaluated the breast and
ovarian cancer risks in BRCA1 and BRCA2 mutation carriers. By examining a population
with a relatively high rate of BRCA1 and BRCA2 mutations (2.5%), and three mutation sites
that harbor most mutations1,2, direct testing of relatives of mutation carriers was feasible. …