Fluorescence in situ hybridization (FISH) is a powerful new technique that allows numerical
chromosome aberrations (
aneuploidy) to be detected in interphase cells. In previous studies, FISH has been used to demonstrate that the
benzene metabolites
hydroquinone and
1,2,4-benzenetriol induce
aneuploidy of chromosomes 7 and 9 in cultures of human cells. In the present study, we used an interphase FISH procedure to perform cytogenetic analyses on the blood cells of 43 workers exposed to
benzene (median = 31 ppm, 8-hr time-weighted average) and 44 matched controls from Shanghai, China. High
benzene exposure (> 31 ppm, n = 22) increased the hyperdiploid frequency of chromosome 9 (p < 0.01), but lower exposure (< or = 31 ppm, n = 21) did not. Trisomy 9 was the major form of
benzene-induced hyperdiploidy. The level of hyperploidy in exposed workers correlated with their urinary
phenol level (r = 0.58, p < 0.0001), a measure of internal
benzene dose. A significant correlation was also found between hyperdiploidy and decreased absolute lymphocyte count, an
indicator of
benzene hematotoxicity, in the exposed group (r = -0.44, p = 0.003) but not in controls (r = -0.09, p = 0.58). These results show that high
benzene exposure induces
aneuploidy of chromosome 9 in nondiseased individuals, with
trisomy being the most prevalent form. They further highlight the usefulness of interphase cytogenetics and FISH for the rapid and sensitive detection of
aneuploidy in exposed human populations.