At ASCO this week, Nobel laureate Elizabeth Blackburn chaired session during which she presented her work on telomeres and cancer. Telomeres, the regions of DNA at the ends of chromosomes, protect chromosomes from deteriorating or fusing with one another. When telomeres erode away, cells die, Blackburn said. Telomerase, the enzyme that continually adds DNA to the ends of telomeres to replenish them, has been implicated in cancer, as it makes cells "immortal" and allows them to grow out of control. But by mutating telomerase, researchers can make those cells mortal, Blackburn said.