Dr. Zwelling is a board-certified internist and medical oncologist. He was trained at Duke University, Duke Medical School and Duke Hospital after which he completed his oncology training at the National Cancer Institute. He started his research career at NCI and in 1984 moved to The University of Texas MD Anderson Cancer Center where he rose to the rank of Professor of Medicine and Pharmacology. He returned to business school at the University of Houston, graduating in 1993. He then gravitated to research administration.