“Most current research into the causes of cancer focuses on genes and environmental triggers. Evolutionary biologist Paul Ewald of the University of Louisville in Kentucky argues that scientists have overlooked the most important cause: parasites, especially viruses. Blending medicine and Darwinian biology, Dr. Ewald considers cancer and other diseases from the pathogen’s point of view, showing how natural selection determines why the smallpox virus, for instance, is a ruthless killer while viruses for the common cold are relatively benign. He says that once we identify the viruses that trigger cancer, we can work to prevent their transmission and force them to evolve from fatal scourges into mere nuisances, eventually turning cancer into a manageable disease.
To progress toward cancer, you need a few specific genes to be mutated, within a limited number of cell divisions, to cause the cells to divide uncontrollably. But if you mutated almost any of the other 30,000 genes, the cells would die or be crippled. So how do all those specific mutations occur so rapidly without destroying the cells? It turns out that each virus that’s been studied and associated with cancer—such as hepatitis B with liver cancer or human papilloma virus with cervical cancer—evolves characteristics that allow it to target those genes immediately upon infection. They’re pushing cells to the brink of cancer because the cells will grow faster with the virus embedded inside and won’t be able to stop dividing. These viruses don’t really benefit if you get cancer, but they do benefit when the viral genome can replicate and persist despite a sophisticated immune system.
Viruses push cells to the brink; additional mutations from genetic defects or the environment are needed for full-blown cancer. Keep in mind that the vast majority of mutating agents provoke cells to stop functioning or to die, meaning there is no chance for those mutations to cause cancer. Without an infection, the few mutated cells that could potentially cause cancer stop proliferating after several divisions. But infected cells can reach such high numbers that the progression to cancer is not terminated by the many mutations that kill the cells or make them nonfunctional. The small percentage that are cancer-causing can continue to proliferate.
You can test this idea by looking at the earliest stages of dysregulation. You should find that the virus is always there, but you’re not going to find the mutations that we know are associated with that cancer. That has been done with cervical cancer. If you look at the very early stages, the virus is always there, but the mutations are there only maybe 10 percent of the time."
Source: Discover Magazine
Posted: True Health Is True Wealth
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