PIK3CA

Phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha - a specific mutation within the PI3 (phosphoinositide 3) kinase pathway or a gene copy number variation; aberrations along the PI3K pathway are associated with many cancers. Cancers that may benefit from testing for this biomarker: colorectal, brain (glioblastoma), gastric, breast, lung, ovarian.

resistance to lapatinib (Tykerb®), cetuximab (Erbitux®), and panitumumab (Vectibix); decreased response to trastuzumab (Herceptin®)