Polymorphisms of alcohol dehydrogenase 2 and aldehyde dehydrogenase 2 and colorectal cancer risk in Chinese males

AIM: To evaluate the relationship between drinking and polymorphisms of alcohol dehydrogenase 2 (ADH2) and/or aldehyde dehydrogenase 2 (ALDH2) for risk of colorectal cancer (CRC) in Chinese males. METHODS: A case-control study was conducted in 190 cases and 223 population-based controls. ADH2 Arg47His (G-A) and ALDH2 Glu487Lys (G-A)genotypes were identified by PCR and denaturing high-performance liquid chromatography (DHPLC). Information on smoking and drinking was collected and odds ratio (OR) was estimated. RESULTS: The ADH2 A/A and ALDH2 G/G genotypes showed moderately increased CRC risk. The age- and smoking-adjusted OR for ADH2 A/A relative to G/A and G/G was 1.60 (95% CI=1.08-2.36), and the adjusted OR for ALDH2 G/G relative to G/A and A/A was 1.79 (95% CI=1.19-2.69). Signif icant interactions between ADH2, ALDH2 and drinking were observed. As compared to the subjects with ADH2 G and ALDH2 A alleles, those with ADH2 A/A and ALDH2 G/G genotypes had a signif icantly increased OR (3.05, 95% CI= 1.67-5.57). The OR for CRC among drinkers with the ADH2 A/A genotype was increased to 3.44 (95% CI= 1.84-6.42) compared with non-drinkers with the ADH2 G allele. The OR for CRC among drinkers with the ALDH2 G/G genotype was also increased to 2.70 (95% CI= 1.57-4.66) compared with non-drinkers with the ALDH2 A allele. CONCLUSION: Polymorphisms of the ADH2 and ALDH2 genes are significantly associated with CRC risk. There are also signifi cant gene-gene and gene- environment interactions between drinking and ADH2 and ALDH2 polymorphisms regarding CRC risk in Chinese males.

Genetic polymorphisms of ADH2 and ALDH2 association with esophageal cancer risk in southwest China

AIM＂ TO evaluate the impact of alcohol dehydrogenase 2 （ADH2） and aldehyde dehydrogenase 2 （ALDH2） polymorphisms on esophageal cancer risk. METHODS;One hundred and ninety-one esophageal cancer patients and 198 healthy controls from Yanting County were enrolled in this study. ADH2 and ALDH2 genotypes were examined by polymerase-chain-reaction with the confronting-two-pair-primer （PCR-CTPP） method. Unconditional logistic regression was used to calculate the odds ratios （OR） and 95% confidence interval （95% CI）. RESULTS; Both ADH2＊1 allele and ALDH2＊1/＊2 allele showed an increased risk of developing esophageal cancer. The adjusted OR （95% CI） for ADH2＊1 allele compared with ADH2＊2/＊2 was 1.65 （95% CI = 1.02-2.68） and 1.67 （95% CI = 1.02-2.72） for ALDH2＊1/＊2 compared with ALDH2＊1/＊1. A significant interaction between ALDH2 and drinking was detected regarding esophageal cancer risk, the OR was 1.83 （95% CI = 1.13-2.95）. Furthermore, when compared with ADH2＊2/＊2 and ALDH2＊1/＊1 carriers, ADH2＊1 and ALDH2＊2 carriers showed an elevated risk of developing esophageal cancer among non-alcohol drinkers