He has also been consulting physician and associate attending physician in the Department of Medicine at Memorial Sloan-Kettering Cancer Center as well as assistant clinical professor of medicine in the Department of Medicine at Cornell University Medical School and assistant attending physician at Memorial Hospital. Dr. Hakes completed his residencies at St. Lukes Hospital and Memorial Hospital in New York City. Dr. Hakes is a member of several scientific and medical societies including the American College of Physicians, American Society of Clinical Oncology and the New York Academy of Science. He is the author of over 100 articles.