[DNA repair and carcinogenesis].

Recent research support the idea that DNA damage is the initial event in the process of carcinogenesis. Involvement of DNA repair in the fixation of DNA damage leading to cancer has been suggested by the presence of several cancer-prone hereditary diseases associated with DNA repair deficiency. Among them, xeroderma pigmentosum has been most extensively investigated and the "SOS response" hypothesis, originally implied to the mechanism of mutagenesis in bacteria, appears to be an attractive hypothesis for the understanding of the cancer-proneness in xeroderma pigmentosum. The DNA repair of ionizing radiation damage, however, has not been clearly demonstrated in association with the process of radiation carcinogenesis, and further studies will be needed to understand the mechanisms of radiation carcinogenesis and the involvement of DNA repair in it.