An improved version of a yeast - derived drug called DON could block cancer cells from producing glutamine ( which is important for metabolism ) without the severe side effects of its 1950s predecessor , researchers from the Johns Hopkins School of Medicine in Baltimore have found . When DON was administered to patients with colon cancer , the tumours shrank and almost disappeared compared with a 5x growth in tumors in the control group . A study out today shows that an updated version of a failed cancer drug can not only prevent tumor cells from using an essential nutrient, but also spur immune cells to attack the growths. In addition , T cells — important in destroying cancer cells — were able to switch to alternative sources of raw materials , whereas tumour cells could not .
An improved version of a yeast - derived drug called DON could block cancer cells from producing glutamine ( which is important for metabolism ) without the severe side effects of its 1950s predecessor , researchers from the Johns Hopkins School of Medicine in Baltimore have found . When DON was administered to patients with colon cancer , the tumours shrank and almost disappeared compared with a 5x growth in tumors in the control group . In addition , T cells — important in destroying cancer cells — were able to switch to alternative sources of raw materials , whereas tumour cells could not .