Targeting the phosphoinositide 3-kinase pathway in cancer

The phosphoinositide 3-kinase (PI3K) pathway is a key signal transduction system that links oncogenes and multiple receptor classes to many essential cellular functions, and is perhaps the most commonly activated signalling pathway in human cancer. This pathway therefore presents both an opportunity and a challenge for cancer therapy. Even as inhibitors that target PI3K isoforms and other major nodes in the pathway, including AKT and mammalian target of rapamycin (mTOR), reach clinical trials, major issues remain. Here, we highlight recent progress that has been made in our understanding of the PI3K pathway and discuss the potential of and challenges for the development of therapeutic agents that target this pathway in cancer.