Continuous improvement of appropriate methods of dealing with cancer require active search for the possibility of applying more and newer targeted therapies. Scientific reports, in addition to best-described proteins KRAS, PI3K emphasize the important role in carcinogenesis. This paper presents overview PIK3CA mutations in the path PI3K/PTEN/Akt the most common cancers. Targeted to stop the most important components of this path can be used to create targeted therapies. PIK3CA mutation may also be a predictive factor in the selection of targeted therapies. A lot of questions remain unanswered such as: how the structure and biochemical effects of intracellular affect different mutations in PIK3CA, and all mutations in the gene lead to the activation of p110a subunit? Additional research on the biochemical structure and cell structure are necessary to complete the discovery of PIK3CA gene function and, in particular subunits of p110a.