Fifteen cigarettes: all it takes to harm genes..

December 18, 2009 - One genetic mutation occurs on average for every 15 cigarettes that a typical lung-cancer patient smokes, according to a study that has identified for the first time all of the mutations acquired during the lifetime of a cancer patient.

PAPER: A small-cell lung cancer genome with complex signatures of tobacco exposure, Erin D. Pleasance et al., Nature advance online publication,December 16, 2009, ABSTRACT..

Scientists have completed a full genetic analysis of the genomes of cancer patients, and hope the information will lead to a fundamental understanding of the causes of cancer – and possibly drugs and treatments – by identifying the mutations that turn a healthy cell into a cancerous tumour cell. They studied a lung-cancer victim who had built up about 23,000 DNA mutations in his lung cells that were linked with exposure to the toxins found in cigarette smoke and had accumulated over his lifetime.

Dr Peter Campbell of the Wellcome Trust Sanger Institute who led the project: "For the first time, we have a comprehensive map of all mutations in a cancer cell. The profile of mutations we observed [in the lung-cancer patient] is exactly that expected from tobacco, suggesting that the majority of the 23,000 we found are caused by the cocktail of chemicals found in cigarettes. On the basis of average estimates, we can say that one mutation is fixed in the genome for every 15 cigarettes smoked," Dr Campbell said.

Reference: 15 cigarettes: all it takes to harm genes Study reveals the genetic mutations suffered by smokers who go on to develop lung cancer by Steve Connor, Science Editor, The, 12/178/2009.