Rapid screening assay for mutagen sensitivity and DNA repair capacity in human peripheral blood lymphocytes

Individual susceptibility to carcinogens, an important determinant of disea se risk, is influenced by host factors such as the ability to repair DNA le sions. In order to identify subjects who are at high risk, we have develope d a microgel electrophoresis assay for use in molecular epidemiological stu dies. The assay was validated in a pilot case-control study: Peripheral blo od lymphocytes were collected from 100 patients with lung cancer and 110 co ntrol patients without cancer and from the same hospital, and stored at -80 degreesC, After thawing, phytohaemagglutinin-stimulated cells were treated with bleomycin at 20 mug/ml for 30 min and the extent of DNA damage and DN A repair capacity were determined by microgel electrophoresis. Peripheral b lood lymphocytes from patients with lung cancer were significantly more sen sitive to mutagens than those from controls and showed reduced DNA repair c apacity (both P < 0.001). Both endpoints were independent risk factors for smoking-related lung cancer. Repeated analysis of peripheral blood lymphocy tes from the same individual demonstrated good reproducibility of the assay . Cryopreservation of the lymphocytes for <less than or equal to>12 months did not significantly affect their sensitivity. Our standardized microgel e lectrophoresis assay is suitable for determining individual sensitivity to mutagens and DNA repair capacity: it is sensitive and faster than cytogenet ic assays, and can be applied to native and cryopreserved peripheral blood lymphocytes.