Study: Two-thirds of cancer caused by bad luck

A new study on cancer has an answer to the question, "Why me?"

Researchers at Johns Hopkins University found that on average, 66 per cent of cancer mutations are caused by random DNA copying errors in your body, simply bad luck.  

Another 29 per cent was caused by the environment, and only 5 per cent was hereditary.

The numbers vary for different cancer types. They looked at 32 different types and lung cancer, for example, was shown to be caused by the environment, mostly smoking, 65 per cent of the time.

The study authors say that random mutations are like typos made by your body. When a cell divides, it makes mistakes when copying the DNA. The mutations often happen in parts of the DNA that are not important, but other times it can cause cancer.

The researchers say this should not cause you to give up on a healthy lifestyle.