Dumb Luck Plays a Crucial Role in Developing Cancers

A new study from John Hopkins University revealed the risk of a person developing cancer is more likely to be influenced by random chance than environmental factors.

The study, published in the journal Science, showed that over half of genetic mutations that develop into cancer are caused by random mistakes made as stem cells divide while environmental factors only contributed more than a quarter of the genetic mutations.

"Every time a perfectly normal cell divides, as you all know, it makes several mistakes -- mutations," explained co-author Dr. Bert Vogelstein, from John Hopkins University, in a briefing as reported by CNN. "Now most of the time, these mutations don't do any harm. They occur in junk DNA, genes unrelated to cancer, unimportant places with respect to cancer. That's the usual situation and that's good luck."

For their study, the researchers developed a new mathematical model to analyze the relationship between the number of normal stem cell divisions and the risk of 17 types of cancer in 69 countries. The data used by the researchers were collected from 423 international cancer databases and represents about 4.8 billion people, or about two-thirds of the world's population.

The researchers found that 66 percent of the genetic mutations leading to cancer are caused by simple random DNA errors occurring when self-renewing cells divide. On the other hand, environmental and hereditary factors contributed to mutations by 29 percent and 5 percent, respectively.

Despite having such a large influence on cancer risk, the researchers noted that a person should not solely rely on his luck to prevent developing cancer. Three or more mutations should occur before it develops into cancer.

If you have bad luck and two of the mutations occur, your lifestyle could play a crucial role. Smoking, obesity, lack of exercise or poor eating habits may provide the third mutation necessary for cancer development.