phosphatidylinositol 3 - kinases are known to be important regulators of signaling pathways . to determine whether pi3ks are genetically altered in cancers , we analyzed the sequences of the p13k gene family and discovered that one family member , pik3ca , is frequently mutated in cancers of the colon and other organs . the majority of mutations clustered near two positions within the p13k helical or kinase domains . pik3ca represents one of the most highly mutated oncogenes yet identified in human cancers and is useful as a diagnostic and therapeutic target .