<P> This model of cancer in cell culture accurately describes the role of telomerase in actual human tumors . Telomerase activation has been observed in ~ 90% of all human tumors, suggesting that the immortality conferred by telomerase plays a key role in cancer development . Of the tumors without TERT activation, most employ a separate pathway to maintain telomere length termed Alternative Lengthening of Telomeres (ALT). The exact mechanism behind telomere maintenance in the ALT pathway is unclear, but likely involves multiple recombination events at the telomere . </P> <P> Elizabeth Blackburn et al., identified the upregulation of 70 genes known or suspected in cancer growth and spread through the body, and the activation of glycolysis, which enables cancer cells to rapidly use sugar to facilitate their programmed growth rate (roughly the growth rate of a fetus). </P> <P> Approaches to controlling telomerase and telomeres for cancer therapy include gene therapy, immunotherapy, small - molecule and signal pathway inhibitors . </P> <P> The ability to maintain functional telomeres may be one mechanism that allows cancer cells to grow in vitro for decades . Telomerase activity is necessary to preserve many cancer types and is inactive in somatic cells, creating the possibility that telomerase inhibition could selectively repress cancer cell growth with minimal side effects . If a drug can inhibit telomerase in cancer cells, the telomeres of successive generations will progressively shorten, limiting tumor growth . </P>

What would be a direct result of an increased number of blood cells