Mitomycin C-induced damage and repair in human and pig lymphocytes.

Human and pig lymphocytes were used to compare the chromosomal sensitivity to MMC and the efficiency of repair of MMC-induced DNA adducts. No significant interspecies differences were found. The results obtained show that SCE frequencies are linearly correlated with MMC doses. During the G0 period there are indications that lymphocytes may half-repair the DNA-interstrand crosslinks transforming bi- into mono-adducts. SCEs induced by MMC decrease to near control levels in the second cell cycle. Therefore, most MMC lesions responsible for SCEs should be repaired between the moment in the first S phase in which they induce the exchanges and the onset of the second S period.