Studies have shown that 90 percent of cancer cells contain large amounts of an enzyme called telomerase.[6] Telomerase is an enzyme that replenishes the worn away telomeres by adding bases to the ends and thus renewing the telomere. A cancer cell has in essence turned on the telomerase gene, and this allows them to have an unlimited amount of divisions without the telomeres wearing away. Other kinds of cells that can surpass the Hayflick limit are stem cells, hair follicles, and germ cells.[7] This is because they contain raised amounts of telomerase.