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.

亚甲基四氢叶酸还原酶基因多态和叶酸摄取与乳腺癌的发病风险

目的研究亚甲基四氢叶酸还原酶（5，10-methylenetetrahydrofolate reductase，MTHFR）基因C677T、A1298C多态、饮食叶酸摄取与女性乳腺癌发病风险的关系。方法采用病例一对照研究，收集江苏省乳腺癌患者669例，选取682名健康人作为对照，用包括83个饮食项目的定量问卷表调查研究对象的饮食状况。采用聚合酶链反应．限制性片段长度多态性（PCR．RFLP）技术检测624例患者和624名对照者的MTHFRC677T和A1298C基因型，用非条件logistic回归进行分析，计算比值比（OR）。结果病例组的MTHFRC677TC／C，C／T和T／T基因型分别为32．37％（202／624）、48．88％（305／624）和18．75％（117／624），对照组分别为37．66％（235／624）、48．24％（301／624）和14．10％（88／624），两组的基因型分布差异有统计学意义（χ^2=6．616，P=0．037）。T／T基因型者的乳腺癌发病风险显著升高[调整OR值为1．62（95％CI值：1．14～2．30）]。病例组的MTHFRA1298CA／A、A／C和C／C基因型分别为71．47％（446／624）、27．08％（169／624）和1．44％（9／624），对照组分别为68．11％（425／624）、30．13％（188／624）和1．76％（11／624），两组间的基因型分布差异无统计学意义（χ^2=1．716，P=0．424）。病例组的饮食叶酸摄取量[（263．00±137．38）μg／d]显著低于对照组[（285．12±149．61）μg／d]（t=-2．830，P=0．005）。与最低三分位组（≤199．08μg／d）相比，叶酸最高摄取量组（≥315．11μg／d）的OR值为0．70（95％CI值：0．53～0．92）。在MTHFR A1298CA／A基因型者中，叶酸中间摄取量组（199．09～315．10μg／d）与最高摄取量组的OR值分别为0．89（95％CI值：0．62—1．27）、1．69（95％CI值：1．20～2．36），其线性趋势检验χ^2=11．372，P=0．001。结论本研究结果显示MTHFR遗传多态、饮食叶酸摄取与乳腺癌的发病风险相关。