Explain how a telomerase inhibitor might be an effective cancer treatment.

Some cells contain an enzyme, telomerase, which makes extra telomere repeats, keeping the number of telomere repeats constant from one cell division to another. Telomerase is active in more than 90 of cancers, allowing cancer cells to divide indefinitely. Because telomerase is not active in most cells of the body but is active in cancer cells, the development of a telomerase inhibitor may prove to be an effective treatment for cancer. If a drug can shut off telomerase, the chromosomes in cancer cells would shorten in each cell division, leading to a halt in tumor growth and the eventual death of the tumor cells.