Lewis C. Cantley (born February 20, 1949) is an American cell biologist and biochemist who has made significant advances to the understanding of cancer metabolism. Among his most notable contributions are the discovery and study of the enzyme PI-3-kinase, now known to be important to understanding cancer and diabetes mellitus. He is currently Meyer Director and Professor of Cancer Biology at the Sandra and Edward Meyer Cancer Center at Weill Cornell Medicine in New York City. He was formerly a professor in the Departments of Systems Biology and Medicine at Harvard Medical School, and the Director of Cancer Research at the Beth Israel Deaconess Medical Center, in Boston, Massachusetts. In 2016, he was elected Chairman of the Board for the Hope Funds for Cancer Research.