Because cancer involves so many genes, many scientists doubt that gene therapy alone can treat cancer's many variations, especially in the immediate future. Another avenue is the study of how DNA regulates the destruction of old, worn-out cells, a necessary and normal process to prevent damaged cells from reproducing. The ends of chromosomes have sections called telomeres.
Young cells have long strings of telomeres at the tips of their chromosomes.
Each time a cell divides, a portion of this string breaks off. Eventually, when the length of the telomere string becomes very short, the cell stops reproducing. Cancer cells bypass this death sentence by making an enzyme that prevents the telomere chain from shortening. If scientists can deactivate this enzyme, they will prevent the cancer cells from trying to live on forever.