MUTAGEN SENSITIVITY EXHIBITS A DOSE-RESPONSE RELATIONSHIP IN CASE-CONTROL STUDIES

We have been quantitating, as a marker of cancer susceptibility, induc ed chromatid breaks in lymphocyte cultures exposed to chemical mutagen s, This report highlights the consistency of the results from two case -control studies, using different methods of presenting the data, In b oth the lung cancer case-control study, which used bleomycin, a radiom imetic agent, as the test mutagen, and the melanoma study, which used 4-nitroquinoline-oxide, an W-mimetic agent, the mean number of breaks/ cell was significantly higher in the cases compared,vith the controls, When the data were dichotomized at the 75th percentile of breaks in t he control populations, significantly elevated adjusted odds ratios (3 .7 and 5.0, respectively) were detected, Dose-response relationships w ere evident in both studies when the data were categorized by quartile s of breaks/cell in the controls, with highest risk estimates being in the top quartile of induced breaks. The potential for extending this assay to other cancer sites, using a variety of test mutagens, is exci ting.