Alfred Knudson, the cancer researcher who developed the two-hit hypothesis, has died, the Philadelphia Inquirer reports. He was 93.
Knudson, who was at the Fox Chase Cancer Center for 40 years, published with his two-hit hypothesis for cancer in 1971 after studying children with retinoblastoma, the Associated Press adds. His theory argues that two copies of a damaged gene needed for someone to develop cancer: people with familial cancers inherit one damaged copy and then develop disease when the other copy becomes damaged, while people who have nonhereditary cancers have to get both hits throughout their lifetime, which is why they tend to develop disease at later in life.
"This was all conceptual work," Jonathan Chernoff, the scientific director at Fox Chase and an oncologist, tells the Philadelphia Inquirer. Chernoff adds that the tools to confirm Knudson's hypothesis weren't around until some 10 years after he proposed it.
"He won everything but the Nobel Prize, and he might have won that, too, if he had lived a little longer," Chernoff adds.