The phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (the HUGO-approved official symbol = PIK3CA; HGNC ID, HGNC:8975), also called p110α protein, is a class I PI 3-kinase catalytic subunit. The human p110α protein is encoded by the PIK3CA gene.
The involvement of p110α in human cancer has been hypothesized since 1995. Support for this hypothesis came from genetic and functional studies, including the discovery of common activating PIK3CA missense mutations in common human tumors. It has been found to be oncogenic and is implicated in cervical cancers.PIK3CA mutations are present in over one-third of breast cancers, with enrichment in the luminal and in human epidermal growth factor receptor 2-positive subtypes. While substantial preclinical data show an association with robust activation of the pathway and resistance to common therapies, clinical data do not indicate that such mutations are associated with high levels of pathway activation or with a poor prognosis. It is unknown whether the mutation predicts increased sensitivity to agents targeting the P3K pathway.
Due to the association between p110α and cancer, it may be an appropriate drug target. Pharmaceutical companies are designing and characterizing potential p110α isoform specific inhibitors. The presence of PIK3CA mutation may predict response to aspirin therapy for colorectal cancer.
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