Cancer "random" in two thirds of cases?

Interesting statistical study.....

"The mistakes, or mutations, cause cancer to happen because even a tiny error in DNA can make cells multiply out of control, the study said. Scientists had thought these mutations resulted mainly from two things: Either the mutation was inherited, or it was caused by outside factors that can damage DNA, such as cigarette smoke or ultraviolet radiation, the researchers wrote.  

But a third cause — random mistakes — actually accounts for two-thirds of these mutations, said the new study, published today (March 23) in the journal Science.

http://www.livescience.com/58393-cancer-caused-by-random-dna-mistakes.html"