Use of DNA Repair Synthesis in Detecting Organotropic Actions of Chemical Carcinogens 1

Summary

A combined in vivo and in vitro system for estimating carcinogen-induced DNA alterations was employed to examine the organotropic action of two carcinogens, 4-nitroquinoline-1-oxide (4NQO) and dimethylnitrosamine (DMN). A DNA repair synthesis, which follows 4NQO- or DMN-induced DNA alterations, was found to occur only in those tissues from which neoplasms arise. No detectable DNA repair synthesis was observed after application of the nononcogenic 4NQO metabolite, 4-aminoquinoline-1-oxide (4NH₂QO). This novel in vivo and in vitro combination system may prove to be a suitable tool to detect organotropic carcinogens and to identify tissues which may give rise to neoplasms.