Random Mutations and Cancer

We all know that eating a healthy diet, not smoking, and avoiding alcohol, among other things, is supposed to minimize your risk of developing cancer.  But what if you did everything right, and you still got it?

In a new study, scientists at Johns Hopkins Kimmel Cancer Center have found that random, unpredictable DNA copying mistakes account for nearly two-thirds of the mutations that cause cancer.

Their research is based on a new mathematical model, which uses DNA sequencing and epidemiological data from a round the world.

They say that about 40% of cancers can be prevented by avoiding unhealthy environments and lifestyles.  The ones that are caused by random mutations however, occur despite living a healthy life style and avoidance of known risk factors.

Age also seems to play a role.  As we age, there is more of a chance for a mistake to be made when DNA is being copied.  The more cells divide, the greater the chance for copying mistakes.

In a previous study, done by Tomisetti and Volgelstein, the researchers say that DNA copying errors could explain why cancers such as those of the colon, occur more commonly than other cancers such as those of the brain.

They also said that in order for a cell to become cancerous, 2 or more critical gene mutations must occur.  These can be due to random DNA copying errors, the environment, or inherited genes.

The researchers used pancreatic cancer to demonstrate their mathematical model.  When the critical mutations were added together, 77% are due to random copying errors, 18% are environmental factors, and 5% are hereditary .  Cancers such as those of the brain, bone, and prostate are due to random copying errors.  Lung cancer however, is different in that 65% of all mutations are due to environmental factors such as smoking, and 35% are because of random copying errors

Despite these findings, people are still encouraged to avoid the known risk factors.  We still have a long way to go in our understanding of cancer.  However, research findings such as this slowly add to our knowledge.  Hopefully one day we can cure this disease.



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