In addition to the extensive TP53 mutations cataloged in both ER-positive and triple negative cases, multiple genes (e.g., CDH1, AKT1, NCOR1, DYNC2H1, BIRC6, MYO18B) encoding the interacting components of cancer cell line-specific PPIs displayed significant rates of mutation in each the respective breast cancer molecular subtypes (Supplementary Figs. 6, 7), suggesting that this mutational burden impacts multi-protein complexes directly and consequently elicits distinct malignant phenotypes as noted recently by ref. 46. This evidence concerns the gene BIRC6 and breast cancer.