PIK3CA and cancer: From previous studies, mutations in various genes involved in the oncogenesis of CRC (e.g., APC, TP53, SMAD4, KRAS, and PIK3CA) and activation of cancer signaling pathways (e.g., WNT, RAS/MAPK, PI3K, TGF-β, P53, and DNA mismatch-repair) caused by these gene mutations have been reported [4].