BRCA1 and neoplasm: The broad spectrum kinase inhibitor Dasatinib, which was able to block LYN Y397 phosphorylation in mammary epithelial cells in a dose-dependent manner (Figure S3B), inhibited growth of three mouse BRCA1 tumor-derived cell lines (half-maximal inhibitory concencetration [IC50] 0.1–1 μM) and the human BRCA1 mutant HCC1937 line (IC50 0.1 μM) (Figures S3C and S3D).