MOLECULAR CYTOGENETIC ANALYSIS OF BUCCAL CELLS AND LYMPHOCYTES FROM BENZENE-EXPOSED WORKERS

Benzene is a well-characterized human carcinogen and clastogen still p resent in both the occupational and general environment, However, the levels of benzene encountered today are, in most cases, relatively low and new methods, more specific and sensitive than classical cytogenet ics, are probably needed to assess if current benzene exposures pose a genotoxic risk to human health, Bearing in mind the leukaemogenic act ion of benzene, blood lymphocytes appear to be a suitable cell system for biomonitoring studies, Buccal epithelium is an alternative source of tissue for monitoring human exposure to inhaled occupational and en vironmental genotoxicants. New molecular cytogenetic techniques allowi ng us to specifically study clastogenic or aneugenic events in human c ells may provide the additional sensitivity required, In the present s tudy, fluorescence in situ hybridization was used to examine the conte nt of micronuclei (MN) (using the pan-centromeric DNA probe SO-alpha A llCen) in lymphocytes and buccal cells and to detect numerical abnorma lities of chromosome 9 (using a chromosome 9 centromere-specific alpho id DNA probe) in buccal cells from a population occupationally exposed to benzene in an Estonian petrochemical plant, Age-matched Estonian v olunteers were used as a control group, Individual benzene exposure le vels were estimated to be around 1 p.p.m. (8 h time-weighted average), No increases in the frequency of total MN, MN harbouring whole chromo somes or acentric chromosomal fragments or chromosome 9 numerical abno rmalities were detected in relation to benzene exposure in the present study, The lack of positive results was consistent in both buccal cel ls and lymphocytes, indicating that the benzene exposure levels encoun tered did not induce detectable clastogenic or aneugenic effects in th e exposed workers, Other variables and confounding factors, such as ag e, smoking or alcohol consumption, did not influence any of the multip le cytogenetic biomarkers analysed.