CYP1A1,CYP2E1 and EPHX1 polymorphisms in sporadic colorectal neoplasms

AIM To investigate the contribution of polymorphisms in the CYP1A1, CYP2E1 and EPHX1 genes on sporadic colorectal cancer(SCRC) risk. METHODS Six hundred forty-one individuals(227 patients with SCRC and 400 controls) were enrolled in the study. The variables analyzed were age, gender, tobacco and alcohol consumption, and clinical and histopathological tumor parameters. The CYP1A1 *2A, CYP1A1 *2C CYP2E1 *5B and CYP2E1 *6 polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). The EPHX1 Tyr113 His, EPHX1 His139 Arg and CYP1A1 *2C polymorphisms were detected by real-time PCR. Chisquared test and binary logistic regression were used in the statistical analysis. Haplotype analysis was conducted using the Haploview program, version 2.05.RESULTS Age over 6 2 years was a risk factor for SCRC development(OR = 7.54, 95%CI: 4.94-11.50, P < 0.01). Male individuals were less susceptible to SCRC(OR = 0.55, 95%CI: 0.35-0.85, P < 0.01). The CYP2E1*5B polymorphism was associated with SCRC in the codominant(heterozygous genotype: OR = 2.66, 95%CI: 1.64-4.32, P < 0.01), dominant(OR = 2.82, 95%CI: 1.74-4.55, P < 0.01), overdominant(OR = 2.58, 95%CI: 1.59-4.19, P < 0.01), and log-additive models(OR = 2.84, 95%CI: 1.78-4.52, P < 0.01). The CYP2E1*6 polymorphism was associated with an increased SCRC risk in codominant(heterozygous genotype: OR = 2.81, 95%CI: 1.84-4.28, P < 0.01; homozygous polymorphic : OR = 7. 3 2, 9 5 % C I : 1.85-28.96, P < 0.01), dominant(OR = 2.97, 95%CI: 1.97-4.50, P < 0.01), recessive(OR = 5.26, 95%CI: 1.35-20.50, P = 0.016), overdominant(OR = 2.64, 95%CI: 1.74-4.01, P < 0.01), and log-additive models(OR = 2.78, 95%CI: 1.91-4.06, P < 0.01). The haplotype formed by the minor alleles of the CYP2E1*5B(C) and CYP2E1*6(A) polymorphisms was associated with SCRC(P = 0.002). However, the CYP1A1 *2A, CYP1A1 *2C, EPHX1 Tyr113 His and EPHX1 His139 Arg polymorphisms were not associated with SCRC.CONCLUSION In conclusion, the results demonstrated that CYP2E1*5B and CYP2E1*6 minor alleles play a role in the development of SCRC.

Polymorphisms of GSTM1 and CYP1A1 genes and their genetic susceptibility to prostate cancer in Chinese men

Background Variation in prostate cancer incidence between different racial groups has been well documented, for which genetic polymorphisms are hypothesized to be an explanation. We evaluated the association between polymorphisms in the cytochrome P-450 CYP1A1 （CYP1A1） and glutathione S-transferase M1 （GSTM1） genes and genetic susceptibility to prostate cancer in Chinese men.Methods TWO hundred and eight prostate cancer patients and 230 age matched controls were enrolled in this study. All DNA samples from peripheral blood lymphocytes were genotyped for common genetic polymorphisms of the CYP1A1 and GSTM1 genes using the oligonucleotide microarray （DNA chip） technique and the polymorphism results confirmed by sequencing. The different polymorphisms in prostate cancer patients were also analyzed according to age at diagnosis, prostate specific antigen level, cancer stage and grade （Gleason score）.Results The prevalence of the GSTM1 （0/0） genotype was significantly higher in prostate cancer patients （58.2%） than in controls （41.7%, P〈0.05）. Further analysis demonstrated that the prostate cancer patients with a GSTM1 （0/0） genotype were younger than those with the GSTM1 （＋/＋） genotype （P=-0.024）. No significant differences in the frequency distributions of CYP1A1 polymorphisms were observed between prostate cancer patients and controls.Conclusion GSTM1 （0/0）-gene polymorphism may be linked to prostate cancer risk and early age of Onset in Chinese.