Association of Genetic Polymorphisms, mRNA Expression ofp53andp21with Chronic Benzene Poisoning in a Chinese Occupational Population

Abstract

DNA damage induced by benzene reactive metabolites is thought of as an important mechanism underlying benzene hematotoxicity and genotoxicity, and genetic variation in cell-cycle control genes may contribute to susceptibility to chronic benzene poisoning (CBP). Using a case-control study that included 307 benzene-poisoned patients and 299 workers occupationally exposed to benzene in south China, we aimed to investigate the association between genetic polymorphisms of p53 and p21 and the odds of CBP. To investigate whether benzene exposure may influence mRNA expression of p53 and p21 in benzene-exposed workers, we also chose 39 CBP workers, 38 occupationally benzene-exposure workers, and 37 nonexposure workers in the same region of China. PCR-restriction fragment length polymorphism technique was applied to detect polymorphisms of p53 (rs17878362, rs1042522, and rs1625895) and p21 (rs1801270 and rs1059234), and real-time PCR was applied to detect the quantity of gene mRNA expression. We found that p21 C98A variant genotypes (CA+AA) or C70T variant genotypes (CT+TT) were associated with decreased odds of CBP [odds ratio (OR), 0.51; 95% confidence interval (95% CI), 0.32-0.83, and OR, 0.53; 95% CI, 0.29-0.95, respectively. Further analysis showed the decreased odds of CBP in the subjects with p21 CC/AT diplotype (OR, 0.51; 95% CI, 0.30-0.85). In addition, p53 mRNA expression of CBP workers or benzene-exposure workers was significantly lower than that of nonexposure workers. Although these results require confirmation and extension, our results show that polymorphisms in p21 may be protective against the risk of CBP in the Chinese occupational population.