Large cohort studies of breast tumor samples identified somatic driver mutations in key breast cancer-associated genes, such as PIK3CA (MIM *171834), TP53 (MIM *191170), MAP3K1 (MIM *600982), CDH1 (MIM *192090), AKT1 (MIM *164730), CBFB (MIM *121360), TBX3 (MIM *601621), RB1 (MIM *614041)6–8. Here, RB1 is linked to breast cancer.