After about 50 cell divisions, the telomeres become critically short. If additional cell division causes the telomeres to shorten any further, the chromosomes will become unstable, and the cell will die. Researchers now think that some cancer cells in a developing tumor can survive this crisis if mutations activate the gene for the enzyme telomerase. Such cells could use the enzyme to maintain the length of their telomeres with each cell division. Those cells could achieve immortality and proliferate indefinitely.
Cancer is an extraordinarily complex disease.
People can spend their lives studying DNA repair enzymes alone. But through such work, our understanding of cancer is growing. Each detail that we add represents a possible new opportunity to treat or prevent malignancies. Unlike automobiles, the human body doesn't come with repair manuals. We have to write the book ourselves, and we' re doing that using knowledge gained through basic research.