| Abstract
| - Occupational exposure to hydrocarbon solvents has been found to be associated with an increased risk of exocrine pancreatic cancer (EPC), the human tumor with the highest prevalence of K-ras mutations. Ras genes are critical DNA targets for chemical carcinogens. We analysed the relationship between past occupational exposure to hydrocarbon solvents and mutations in codon 12 of the K-ras gene in 107 incident cases of EPC. Information on occupational factors and life-style was obtained from personal interviews conducted during hospital stay. Occupational exposure to hydrocarbon solvents (aliphatic, aromatic, chlorinated, benzene, other organic solvents) was examined using two methods: expert assessment and the Finnish job-exposure matrix (Finjem). Exposure among K-ras mutated EPC cases (n = 83) was compared with that of K-ras wild-type EPC cases (n = 24). An association between K-ras mutations and solvent exposure was observed with Finjem but barely so with the expert assessment. Over 7-fold increased odds ratios (OR) were found for every group of solvents evaluated with Finjem (all P< 0.05). On the basis of the expert assessment, K-ras mutations were significantly associated only with exposure to benzene in men (OR = 7.07, P< 0.05). When requiring exposure to have occurred according to both the experts and Finjem, over 4-fold risks were obtained for aromatic, aliphatic, and for `any hydrocarbon solvent'. A significantly higher proportion of cases with a mutation from glycine to valine (GGT○ISOdia→GTT) or to aspartic acid (GGT○ISOdia→GAT) were exposed to a hydrocarbon solvent. The results raise the possibility that hydrocarbon solvents might be involved in the pathogenesis of EPC, possibly through indirect modulation of K-ras activation. Since this is only the first study on occupational exposures and K-ras mutations in EPC, studies able to refute or to confirm the findings are required before public health implications, if any, are assessed.
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