The ends of chromosomes in normal cells eventually unravel, causing the cells to die. This does not happen in cancer cells, however. Cancer cells use an enzyme named telomerase to rebuild the chromosome ends, which are called telomeres, in essence making cancer cells immortal. Since the discovery of the link between telomerase and cancer, scientists have been hunting for ways to turn the enzyme off, in hopes that such a therapy could render cancer cells mortal. Now, two Harvard Medical School researchers, Xiao Zhen Zhou and Kun Ping Lu, have discovered the first protein that potently inhibits telomerase, suggesting a potential new cancer therapy and a genetic link between telomeres, cancer, and cell division. Their research was reported in the Nov. 2, 2001, issue of the journal Cell.