[Absence of adaptive DNA repair in xeroderma pigmentosum cells]

Adaptive repair is the restoration of chemically induced DNA breaks in human fibroblasts previously gamma-irradiated at low doses. The adaptive repair in xeroderma pigmentosum (XP) cells was compared to that in normal human fibroblasts. The obtained results suggest that the repair is inducible and error-free. Adaptive repair was not found in XP cells in experiments with 4-NQO. This is correlated with the presence of an excision repair defect in XP.