Chromosome damage and aneuploidy detected by interphase multicolour FISH in benzene-exposed shale oil workers

A multicolour tandem-labelling fluorescence in situ hybridization (FISH) pr ocedure was used to detect chromosome alterations in peripheral blood cells of a group of Estonian petrochemistry workers. Twelve workers employed in benzene production and five cokery workers, together with eight unexposed r ural controls, were enrolled in the study. The methodology employed, based on the in situ hybridization of adjacent centromeric and pericentromeric re gions, allowed the simultaneous detection of both chromosome breakage, invo lving damage-prone pericentromeric regions, and hyperploidy in interphase c ells. Blood smears from all subjects were hybridized with chromosome 1 spec ific probes, in order to detect genotoxic damage in circulating lymphocytes and granulocytes. Moreover, lymphocyte cultures were established, harveste d 48 h following mitogen stimulation and hybridized with the tandem chromos omes 1 and 9 probes. No significant difference in the incidence of breakage was detected in the nucleated cells of blood smears of exposed vs. control subjects. In contrast, modest but significantly increased frequencies of b reakage affecting both chromosomes and 9 were observed in the cultured lymp hocytes of the benzene-exposed workers compared to the unexposed controls, suggesting an expression of premutagenic lesions during the S-phase in vitr o. Across the entire study group, the frequencies of breakage affecting chr omosomes 1 and 9 in the stimulated lymphocytes were highly intercorrelated (p < 0.001). No significant difference was found in the incidence of hyperp loidy among the study groups, although a tendency to higher values was obse rved in benzene-exposed workers. Although the relatively small size of the study groups does not allow firm conclusions on the role of occupational ex posure, the observed patterns are suggestive of effects in the benzene-expo sed workers. This work also shows that tandem labelling FISH can be usefull y applied in human biomonitoring, allowing the simultaneous detection of bo th hyperploidy and chromosome breakage at interphase in different cell type s. (C) 1999 Elsevier Science B.V. All rights reserved.