CYTOGENETIC STUDIES ON THE IN-VITRO GENOTOXICITY OF 4-NITROQUINOLINE-1-OXIDE ON HUMAN-LYMPHOCYTES

Using the UV-mimetic mutagen 4-nitroquinoline-1-oxide (4NQO) to induce genetic damage in human cells (lymphoblastoid lines and primary cultu res of peripheral blood samples), chromosome aberrations were induced by treating the cells with 4NQO at 1 X 10(-5) M for 24 h. The overwhel ming majority of chromosome aberrations was of the chromatid (S + G2) type instead of the chromosome (G1) type. The most common chromatid ab errations were simple breaks, isochromatid breaks, and chromatid excha nges. When the number of chromatid breaks per cell value was used as a measurement for 4NQO sensitivity, lymphoblastoid cells from a xeroder ma pigmentosum patient showed the highest sensitivity, followed by the cells of two melanoma patients and normal persons. These preliminary results suggest that 4NQO may be employed to develop an assay system a s a biomarker for determining UV sensitivity in the human population.