Abstract: The PIK3CA gene codes p100α, the catalytic  subunit of phosphatidylinositol 3-kinase (PI3K) and is involved in the initiating the PI3K/AKT pathway. PIK3CA plays its biological roles through.downstream PI3K pathway. PIK3CA gene mutants can be detected in many kinds of tumors. The mutant PIK3CA gene can abnormally activate PI3K pathway, leading to the abnormal cell cycle, decreased cell adhesion, down regulated apoptosis and neovascularization, and then promotes tumor genesis and development. Recent researches have found that mutant PIK3CA gene is closely correlated with the genesis, development, differentiation, metastasis and drug resistance of colorectal cancer. Research of PIK3CA in colorectal cancer may provide significant evidence for the early diagnosis, gene screen, therapeutic regimen making, recurrence and follow up.

Key words: Colorectal Neoplasms, PI3K pathway