DHAKA: Cancer is often caused by the ‘bad luck’ of random mutations that arise when cells divide, not family history or environmental causes.

US researchers said Thursday, The Straits Times publishes this report on Friday.

The study in the January 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, which is the most common cancer in women, or prostate cancer, which is the second most common cancer in men after skin cancer.

In the adult cancers they did measure, about two-thirds could be explained by random mutation in genes that encourage tumours to grow, while the remaining one third was due to environmental factors and inherited genes.

‘This study shows that you can add to your risk of getting cancers by smoking or other poor lifestyle factors,’ said study author Bert Vogelstein, a professor of oncology at the Johns Hopkins University School of Medicine.

‘However, many forms of cancer are due largely to the bad luck of acquiring a mutation in a cancer driver gene regardless of lifestyle and heredity factors.’

He added that people who live a long time without getting cancer, despite being long-time smokers or being exposed heavily to the sun, do not have ‘good genes’.

‘The truth is, that most of them simply had good luck,’ he added.

BDST: 0724 HRS, JAN 02, 2015