The majority of these aberrations occur in the upstream components of the pathway, such as PIK3CA (p110α catalytic subunit of PI3K), PIK3R1 (p85α regulatory subunit of PI3K), and PTEN. So far, most characterized aberrations of these genes result in elevated production of phosphatidylinositol 3,4,5-triphosphate (PIP3) that activates AKT, which is also frequently aberrant in cancers. This evidence concerns the gene PIK3R1 and cancer.