PIK3CA in cancer: The past 30 years.

Almost thirty years ago, PI3K was discovered as a lipid kinase associated with certain oncoproteins. The first decade of research on PI3K saw the identification, purification and cloning of PI3Kα. The second decade of research was noted for the identification of some of PI3K's activators and effectors. This was accompanied by the discovery that PI3K acts as a retroviral oncogene. The third decade was known for the establishment of the direct involvement of PI3K in cancer, demonstrated by the identification of cancer-specific mutations. Efforts to target PI3K were on the rise from that moment on, accompanied by the first clinical trials for PI3K inhibitor therapies. In the fourth decade of research, PI3K-based cancer drugs will continue to emerge, as will new knowledge regarding other uncovered functions of this protein and pathway.