EFFECT OF DIETARY-COMPONENTS ON HPRT MUTANT FREQUENCIES IN HUMAN T-LYMPHOCYTES

The 6-thioguanine resistance (TG(r)) assay in human T-lymphocytes, whi ch detects mutations at the hprt locus, identifies exposures to enviro nmental mutagens. However, the ability of this assay to detect small i ncreases in mutation rates is limited by the broad range of mutant fre quencies (Mf) in healthy individuals. While subject age, lymphocyte cl oning efficiency, and cigarette smoking history have been shown to inf luence the Mf, these factors account for only a portion of the variabi lity in the Mf in human populations. To investigate the influence of d ietary differences on hprt Mf, 70 women with breast masses were asked to complete a nutritional questionnaire and submit a peripheral blood sample for a TG(r) assay. Multivariate analyses, adjusted for age, clo ning efficiency and total caloric intake, showed significant positive correlations between vitamin A and iron and lnMf (p = 0.03), and a neg ative correlation between total fat and lnMf (p = 0.004). Positive cor relations between dietary fiber and copper and lnMf, and a negative co rrelation between alcohol and lnMf were of borderline significance (0. 05 less than or equal to p less than or equal to 0.07). These results suggest that nutritional components may modulate the hprt Mf Dietary d ifferences may account for a part of the variability observed in hprt Mf in human populations.