Rockefeller University, located on the Upper East Side of Manhattan, is a world-renowned center for research and graduate education in the biomedical sciences, chemistry, and physics. Founded by John D. Rockefeller in 1901, the university has been the site of many important scientific breakthroughs. Rockefeller scientists established that DNA is the chemical basis of heredity, discovered blood groups, showed that viruses can cause cancer, founded the modern field of cell biology, worked out the structure of antibodies, developed methadone maintenance for people addicted to heroin, devised the AIDS "cocktail" drug therapy, and identified the weight-regulating hormone leptin. Twenty-three Nobel Prize winners have been associated with the university, an amazing figure considering that Rockefeller University houses a relatively small amount of labs.