Carcinogen-DNA adducts in bladder biopsies and urothelial cells: a risk assessment exercise

We have determined the levels of DNA adducts (using 32P-postlabelling) in the biopsies of 20 bladder cancer patients and in the exfoliated bladder cells of 36 healthy volunteers. The aims of the study were (a) to estimate the concentration of DNA adducts in cancer cases and controls according to the level of smoking; and (b) to investigate whether bladder cancer cases had higher levels of adducts in bladder cells than healthy controls had. A dose-response relationship between smoking levels and adduct levels was present among both cancer cases and controls. Cancer cases and the controls had similar adduct levels for the same level of smoking. According to a risk assessment exercise, adduct levels among heavy smokers were roughly comparable with those found in mice and dogs treated with bladder carcinogens, at doses which induce a 50% lifetime risk of bladder cancer.