Chromosome 8, occupational exposures, smoking, and acute nonlymphocytic leukemias: a population-based study

In a previous epidemiological study on acute myelocytic leukemia (M. M. Crane et al., Cancer Epidemiol. Biomark. Prev., 5: 639-644, 1996), clonal aberrations in chromosome 8 have been reported to be in excess in smokers and in workers exposed to paints. In that study, cytogenetics was performed after therapy. In our report, we describe a population-based survey on nonlymphocytic leukemias in northern Italy, in which 79 patients (acute myelocytic leukemia, myelodysplastic syndromes, or other nonlymphocytic leukemias) were studied before cytotoxic therapy. We found 9 aberrations involving chromosome 8 (six +8, two -8, and one translocation), whereas abnormalities involving chromosomes 5 and 7 occurred with a low frequency compared with previous studies. Aberrations involving chromosome 8 were associated with smoking (odds ratio, 6.3; 95% confidence interval, 0.9-42.3; among smokers of 10 or more cigarettes/day: odds ratio, 14.2; 95% confidence interval, 1.4-142.3); +8 aberrations were found in 1 of 24 nonsmokers and in 5 of 38 smokers. Three +8 aberrations were found in 22 subjects potentially exposed to solvents or polycyclic aromatic hydrocarbons. The low frequency of chromosome 5 and 7 aberrations in our population-based series (compared with other studies) can be attributed to the recruitment before cytotoxic therapies. Aberrations involving chromosome 8 (particularly +8) were associated with smoking habits. Chromosome 8 includes the c-myc oncogene.