Reference Work Entry

Encyclopedia of Cancer

pp 2892-2894


  • Ben Ho ParkAffiliated withThe Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University Email author 


Phosphatidylinos​itol 3-kinase (PI3-Kinase)


PIK3CA is a human gene that regulates various cellular functions including proliferation and invasion. Because it is an oncogene, its activation by either gene amplification or mutation results in a cellular growth advantage contributing toward cancer formation and progression.


The PI3-Kinase pathway is one of many signaling pathways that are important for cell growth, transformation, adhesion, apoptosis, survival, and invasion. PI3-kinases themselves are heterodimeric lipid kinases composed of catalytic and adaptor/regulatory subunits encoded by separate genes and alternative splicing. The PI3-Kinase enzyme family is organized under three main classes (class I, II, and III), and various subgroups have been categorized based on their primary structure, substrate specificity, and regulation.

The PIK3CA oncogene encodes for the alpha catalytic subunit and, along with the p85 regulato ...

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