Some credit Heidelberger and Duschinsky with the discovery that 5 - fluorouracil markedly inhibited tumors in mice .
Charles Heidelberger , who had earlier found that fluorine in fluoroacetic acid inhibited a vital enzyme , asked Robert Duschinsky and Robert Schnitzer at Hoffman - La Roche to synthesize fluorouracil .
Some credit Charles Heidelberger and Duschinsky with the discovery that 5 - fluorouracil markedly inhibited tumors in mice .
Charles Heidelberger , who had earlier found that fluorine in fluoroacetic acid inhibited a vital enzyme , asked Robert Duschinsky and Robert Schnitzer at Hoffman - La Roche to synthesize fluorouracil .