Smoking causes added mutations in DNA of lung cells

What
A paper published today in Science shows that smoking tobacco causes added mutations in the DNA of lung cells and in the DNA of other cells in the body. This is the first study to show the process by which smoking causes these cancers.

Why
Mutations are changes in DNA, deoxyribonucleic acid. DNA is the genetic code that governs how a cell carries out its tasks. Cancer results when DNA mutations disturb how certain genes function.

This study looked at the DNA changes in the cancers of more than 5,000 patients.  The researchers compared tumor cells from people who smoked with tumor cells from people who never smoked. They found that smokers' tumor cells had more mutations than nonsmokers' tumor cells for almost every type of cell they tested. The researchers were able to estimate the number of mutations caused by smoking a pack of cigarettes per day for a year: every smokers' lung cell amassed, on average, 150 additional mutations.

Previous studies have shown a strong link between smoking and lung cancer and a link between smoking and other types of cancers. But until now, these studies did not show how smoking caused the cellular changes that led to cancer.

Who
The lead co-authors of the paper are Ludmil Alexandrov, PhD, and Sir Michael Stratton, PhD, FMedSci, FRS.

Alexandrov is an Oppenheimer Fellow in the Theoretical Biology and Biophysics Group at Los Alamos National Laboratories and a full member of the Cancer Genetics, Epigenetics and Genomics Research Group at The University of New Mexico Comprehensive Cancer Center.

Stratton is the Director of the Wellcome Trust Sanger Institute and Chief Executive Officer of the Wellcome Genome Campus. He is a Fellow of the Royal Society (FRS) and was Knighted by the Queen in 2013.

When
The paper, "Mutational signatures associated with tobacco smoking in human cancer," was published in the November 3, 2016, online edition of Science.