Frequencies of hprt(-) mutations and bcl-2 translocations in circulating human lymphocytes are correlated with United Kingdom sunlight records

Between 1983 and 1995 we have monitored human populations for evidence of e xposure to environmental mutagens, taking blood samples to measure hprt(-) mutant frequency in T cells and more recently bcl-2 t(14:18) translocation frequency in B cells. We have now analysed data from 785 assays on 448 bloo d samples from 308 normal subjects and find that there is a highly signific ant statistical correlation between hprt- mutant frequency and the sunlight record for the 3 weeks prior to taking the blood sample. We discuss the we aknesses in retrospective studies of this nature and the possibility of spu rious epidemiological correlations that may result. More controlled experim ents can be envisaged that would give a firmer basis to the statistical ass ociations observed. hprt(-) mutations in T cells show little evidence of a UV fingerprint, so that the correlation may be due to immunomodulation rath er than mutation. We also find a correlation between the sunlight record an d bcl-2 translocation, This translocation is found at a low frequency in th e B cells of many normal subjects and is the commonest translocation observ ed in non-Hodgkin's lymphoma. Our results strengthen the case for a link be tween sunlight and this increasingly common cancer.