PIK3CA and breast cancer: Of these 10 mutations, AKT1 p.E17K, three PIK3CA mutations within the PI3Ka (E542K and E545K) and PI3Kc (H1047R) domains and two TP53 mutations (p.R175H and p.R248W) within the DNA binding domain were well established hotspots in breast cancer [48, 49].