1976

Harold Varmus and Michael Bishop’s proto-oncogene theory reorganizes cancer biology, retuning genes again to its center. Their experiments demonstrated “that a precursor of a cancer-causing gene – the ‘proto-oncogene’ . . . was a normal cellular gene. Mutations induced by chemicals or X-rays caused cancer not by ‘inserting’ foreign genes into cells, but by activating such endogenous proto-oncogenes. . . . Cancer genes came from within the human genome” (Mukherjee, 363-364, quoted at 364). In 1982, three labs published finding of isolation of same fragment of DNA, containing a gene called ras, from their respective cancer cells: “they had purified a mutated oncogene from a cancer cell” (376).