The answer is not straightforward, and as yet, not fully understood by the medical profession. Causes of cancer lie not just in environmental factors, but also in genetic factors. Ultimately, changes in DNA are the final determinants in the genesis of cancer. But if the body's repair system is faulty or if cell division occurs before the cell is repaired, the cell replication may result in a mutant gene in the daughter cell. If the mutation occurs at just the right spot on a gene, the cell may be sensitized to the action of carcinogens or promoters.
Promoters cause the cells to proliferate abnormally and accumulate mutations.
According to many physicians, some precautions can be taken to decrease the risk of developing cancer. Americans have been told to avoid prolonged exposure to the sun, to eat more fiber, to take a daily dose of aspirin and to avoid red meat, especially when it's barbecued. Studies have shown these are good precautions against cancer. But since there's no sure-fire method of protection from the disease, oncologists continue to search for better treatments to cure it. By Jennifer Fisher 1970, the National Cancer Act declared a war against cancer.