Cancer at times is simply 'bad luck'

Cancer is often caused by the "bad luck" of random mutations that arise when cells divide, not family history or environmental factors, US researchers said on Thursday.

The study in the Jan 2 edition of the journal Science was led by researchers at Johns Hopkins University and based on a statistical model that includes many types of cancer in a range of human tissues.

However, it did not include breast cancer, the most common form in women, and prostate cancer, the second-most common in men, after skin cancer.