Association of type and location of BRCA1 and BRCA2 mutations with risk of breast and ovarian cancer.

Importance: Limited information about the relationship between specific mutations in BRCA1 or BRCA2 (BRCA1/2) and cancer risk exists.

Objective: To identify mutation-specific cancer risks for carriers of BRCA1/2.

Design, Setting, And Participants: Observational study of women who were ascertained between 1937 and 2011 (median, 1999) and found to carry disease-associated BRCA1 or BRCA2 mutations.