DNA strand breakage and base modification induced by hydrogen peroxide treatment of human respiratory tract epithelial cells

Treatment of human respiratory tract epithelial cells with H 2 O 2 led to concentration‐dependent DNA strand breakage that was highly‐correlated with multiple chemical modifications of all four DNA bases, suggesting that damage is due to hydroxyl radical, OH . . However, the major base damage occurred to adenine. Hence, conclusions made about the occurrence and the extent of oxidative DNA damage on the basis only of changes in 8‐hydroxyguanine should be approached with caution.