DNA damage, DNA repair and carcinogenicity: Tobacco smoke versus electronic cigarette aerosol

•Tobacco smoke induces mainly acrolein- and crotonaldehyde-DNA adducts in lungs.•Tobacco smoke reduces DNA repair in lungs and aldehydes do the same in human cells.•Aldehydes in tobacco smoke are the major driving forces of inducing DNA damage.•E-cigarettes induce acrolein-DNA and methyl-dG adducts in the lungs and bladder.•E-cigarettes induce lung adenocarcinoma and bladder urothelial hyperplasia in mice.