TP53 and breast cancer: Of the 49 cancer-driver genes studied, the most commonly altered genes in this cohort of MpBC included TP53 (68.4%, 13/19), PIK3CA (42.1%, 8/19), and PTEN (15.8%, 3/19) (Fig 1 and S1 Table). In a univariate analysis, the association of TP53, PIK3CA, and PTEN mutations and breast cancer specific survival was determined.