The PIK3CA gene is located on the long arm of chromosome 3. PIK3CA spans nearly 92-Kb and encodes for the 110 kDa catalytic subunit of phosphatidylinositol 3-kinase.
Many mutations were uncovered in the PIK3CA gene with a myriad of clinical consequences. A number of these mutations are involved in cancers. For instance, His1047Arg and Glu545Lys are two common mutations in colorectal cancer. It is important to remember that these mutations are somatic and, hence, they are confined to tumor cells. Other conditions that are associated with PIK3CA mutations include hemimegalencephaly; fibroadipose hyperplasia; and congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal or spinal abnormalities (CLOVES) syndrome. The list of mutations underlying these conditions includes missense and indel mutations.