BRCA1 and breast cancer: BRIP1 was investigated as a breast cancer susceptibility gene in heterozygous carriers because it interacts with other breast cancer predisposing genes such as BRCA1. Seal et al. [21] sequenced the exons and exon–intron boundaries of BRIP1 in 1212 breast cancer cases with a family history of disease and no BRCA mutation and in 2081 controls, and found mutations in nine cases (0.74 %) but only in two controls (0.10 %).