A new UK-based study says new lung cells can replace damaged cells after people stop smoking.
The study was conducted by researchers from the Wellcome Trust Sanger Institute, University College London, and Kyoto University in Japan and was funded by Cancer Research UK and the Wellcome Trust.
During the study, researchers examined lung cells from children, adults who had never smoked, smokers, and ex-smokers to look for DNA mutations. They found thousands of mutations in cells of smokers and ex-smokers, including mutations known to lead to cancer. However, they also found a surprising amount of variation within the samples of cells from ex-smokers.
The researchers found that even in people who had smoked heavily for decades before quitting, some of their cells were near-normal, suggesting the cells had grown since people had stopped smoking. These normal cells were not found in current smokers.