Smoke signals in the DNA of normal lung cells

Surprisingly, ex-smokers’ lungs have a large fraction of healthy cells with nearly normal profiles.

According to the World Health Organization, there are 1.1 billion smokers worldwide and an estimated 1.8 million deaths from lung cancer annually. Lung cancer caused by smoking can take decades to arise, and smokers have up to a 30-fold higher risk of developing the disease than do non-smokers¹. 

https://www.nature.com/articles/d41586-020-00165-7