PIK3CA and cancer: Activating somatic mutations in the phosphatidylinositol‐4,5‐bisphospate 3‐kinase, catalytic subunit alpha gene (PIK3CA) occur frequently in congenital overgrowth syndromes and in human cancer.1PIK3CA encodes the p110 α catalytic subunit of phosphoinositide 3‐kinase (PI3K), that phosphorylates phosphatidylinositol to generate phosphatidylinositol 3,4,5‐trisphosphate (PIP3).