Lwoff, Andre, lwawf, ahn DRAY (1902-1994), a French microbiologist, shared the 1965 Nobel Prize for physiology or medicine with Francois Jacob and Jacques Monod. The three scientists, all members of the Pasteur Institute in Paris, studied the cells of bacteria. They discovered a previously unknown class of genes that regulate other genes. Radiation and some chemicals can damage these regulatory genes and make them function improperly. Without regulation, other genes can become overactive. This overactivity can lead to cell damage or excessive cell growth and division. Since Lwoff and his colleagues discovered regulatory genes, study of their activity has become a major area of cancer research.