H. Robert Horvitz (1947- present) was awarded one-third of the 2002 Nobel Prize in Physiology or Medicine for his discoveries concerning genetic regulation of organ development and programmed cell death. Horvitz's research focused on determining if a specific genetic program controls cell death. His studies involved the round worm Caenorhabditis elegans, which had been identified by fellow Nobel Laureate Sydney Brenner as an ideal organism in which to study programmed cell death. In 1986, Horvitz reported the discovery of the first two "death genes," ced-3 and ced-4, which are necessary for turning on the cell-death program. Later he showed that another gene, ced-9, protects against cell death by interacting with ced-3 and ced-4. Horvitz also established that humans have a counterpart to the ced-3 gene. Scientists later found that most of the genes involved in controlling programmed cell death in C. elegans have human equivalents. Such knowledge about programmed cell death contributed to important advances not only in developmental biology but also in medicine, especially concerning cancer treatments.