PI3K/Akt/mTOR pathway as a target for cancer therapy.

The PI3K/Akt/mTOR pathway regulates several normal cellular functions that are also critical for tumorigenesis, including cellular proliferation, growth, survival and mobility. Components of this pathway are frequently abnormal in a variety of tumors, making them an attractive target for anti-cancer therapy. Inhibition of mTOR in patients with cancer became more feasible after the development of rapamycin analogs with improved pharmacologic properties. The promising activity of these agents in early clinical trials has led to the development of ongoing phase III trials in renal cell carcinoma and breast cancer. Future studies are needed to identify the patients most likely to benefit from this form of therapy, and to define its role in combination with chemotherapy, hormones and growth factor inhibitors.