BRCA1 and breast cancer: LYN is overexpressed in human triple-negative breast cancer (TNBC; the breast cancer subtype most strongly associated with BRCA1 loss) (Choi et al., 2010; Croucher et al., 2013; Hochgrafe et al., 2010; Molyneux et al., 2010) and is also expressed at high levels in mammary tumours from Brca1 conditional knockout mice (Molyneux et al., 2010).