Different mutations on Phosphoinositide-3-kinase α catalytic subunit (PIK3CA) correlated with two distinct (p = 1.97e−12, q = 2.36e−10; Table S3a) breast cancer subtypes: one defined by mutations in the α−helical domain that are predicted to disable interfaces with regulator N-terminal SH2 domains, and another that affects the highly oncogenic kinase domain mutation (H1047R) and is predicted to disable the C-terminal SH2 domain interface (Fig. 4). The gene discussed is PIK3CA; the disease is breast cancer.