Repair excision of alkylated bases from DNA in vivo.

Recent experiments are reviewed which indicate that O6-alkylation of guanine in nuclear DNA constitutes a promutagenic lesion possibly implicated in malignant transformation by monofunctional alkylating carcinogens. The differential capacity of various organs to enzymically excise O6-alkylguanine from their DNA seems to correlate with the organ specificity of the carcinogenic effect.