Carcinogenetic impact of ADH1B and ALDH2 genes on squamous cell carcinoma risk of the esophagus with regard to the consumption of alcohol, tobacco and betel quid

The consumption of alcohol, tobacco and betel quid has been found to be an important contributor to esophageal squamous cell carcinoma (ESCC) in Taiwan. The genotoxic effect of the ADH1B and ALDH2 genes modulating an individual's alcohol-metabolizing capacity on ESCC may be linked to drinking behavior, intake pattern and other exogenous factors. To investigate the interplay of these genetic and environmental factors in determining the risk of ESCC, a multicenter case-control study was conducted. Here, 406 patients with pathology-proven ESCC, as well as 656 gender, age and study hospital matched controls were recruited. Genetic polymorphisms of ADH1B and ALDH2 appeared to correlate with the abstinence of alcohol, though not with tobacco and betel quid. Within the same levels of alcohol consumption, carcinoma risks increased along with an increase in the numbers of ADH1B*1 and ALDH2*2 alleles. The inactive ALDH2*1/*2 genotype was found to multiplicatively interact with a low-to-moderate (0.1-30 g/day) and a heavy (>30 g/day) ethanol intake to increase the ESCC risk (the joint aOR = 14.5 and 102.6, respectively). Among low-to-moderate drinkers, a smoking-dependent carcinogenetic effect for the ADH1B*1/*1 and ALDH2*1/*2+*2/*2 genotypes was recognized, with significant risks found in smokers, but not in nonsmokers. Further, a supra-multiplicative combined risk of ESCC for alcohol and tobacco use was identified among carriers of the ADH1B*1/*1 genotype (p for interaction = 0.042). In conclusion, the interplay of the ADH1B and ALDH2 genotypes, in conjunction with a behaved drinking habit and a practiced drinking pattern, along with continued tobacco consumption, plays an important pathogenic role in modulating ESCC risk.     

Interactive effects of lifetime alcohol consumption and alcohol and aldehyde dehydrogenase polymorphisms on esophageal cancer risks

In our previous study, we found that polymorphisms of alcohol and aldehyde dehydrogenase (ADH1B and ALDH2) are important risks for esophageal squamous cell carcinoma in a Taiwanese population. In this study, we increased the sample size to investigate the modifying effect of lifetime alcohol consumption on the association between ADH1B and ALDH2 genotypes and the risks of esophageal cancer. A multicenter hospital-based case-control study was conducted between August 2000 and June 2004. Three hundred and thirty newly-diagnosed esophageal squamous cell carcinoma patients and 592 controls were recruited from National Taiwan University Hospital in Taipei and Kaohsiung Veterans General Hospital and Kaohsiung Medical University Hospital in Kaohsiung, Taiwan. Controls were matched to the case patients by gender and age within 4 years (case:control = 1:1-4). Polymorphisms of ADH1B and ALDH2 were genotyped by the method of PCR-RFLP. Individuals with ADH1B*1/*1 genotype had a 3.99-fold risk (95% CI = 2.13-7.48) of developing esophageal cancer, compared with those with ADH1B*2/*2 genotype, after adjusted for appropriate covariates. Individuals with ALDH2*1/*2 and ALDH2*2/*2 had 4.99-fold risk (95% CI = 3.11-7.99) and 4.24-fold risk (95% CI = 1.52-11.84), respectively, of developing esophageal cancer, compared with those with ALDH2*1/*1, after adjusted for appropriate covariates. We also found a modifying effect of lifetime alcoholic consumption on the association between genotypes of ADH1B and ALDH2 on esophageal cancer risk. These results suggest that ADH1B and ALDH2 polymorphisms play a pivotal role on esophageal cancer and that the effect of these polymorphisms was modified by the amount of alcohol consumed.     

Meta-analysis of ALDH2 variants and esophageal cancer in Asians

Alcohol drinking is considered a risk factor for esophageal cancer, and exposure to high levels of acetaldehyde, the principal metabolite of alcohol, may be responsible. Individuals homozygous for the *2 variant allele of aldehyde dehydrogenase 2 (ALDH2) are unable to metabolize acetaldehyde, which prevents them from alcohol drinking, whereas those with *1/*2 have a 6-fold higher blood acetaldehyde concentration postalcohol consumption with respect to *1*1. We carried out a meta-analysis of ALDH2 and esophageal cancer searching for relevant studies on Asians in Medline and EMbase up to May 2011, and investigated the association between this genotype variation and esophageal cancer risk. A total of 2,697 cases and ,6344 controls were retained for the analysis. The pooled OR (95% CI) for ALDH2*1/*2 was 2.47 (95%CI: 1.76-3.46) compared with ALDH2*1/*1. ALDH2*2/*2 showed a non-significant decreased risk for esophageal cancer with OR of 0.6 (0.26-1.38). ALDH2*1/*2 individuals showed a higher risk of esophageal cancer among moderate and heavy alcohol users [2.17(1.95-2.43) and 3.20(2.78-3.70), respectively]. Moderate drinkers with ALDH2*2/*2 showed strong esophageal cancer risk [OR(95%CI)=8.52(3.81-19.04)] compared with ALDH2*1/*1 carriers among heavy drinkers than non-drinkers and moderate drinkers (OR=7.05). Our finding showed that ALDH2*1/*2 genotype increases the risk of esophageal cancer, while the ALDH2*2/*2 genotype reduces the risk, presumably preventing people from consumption due to discomfort. Drinking clearly modifies the effect of ALDH2 on esophageal cancer risk in Asians.     

Genetic polymorphisms of alcohol and aldehyde dehydrogenases, and drinking, smoking and diet in Japanese men with oral and pharyngeal squamous cell carcinoma

The genetic polymorphisms of aldehyde dehydrogenase-2 (ALDH2), alcohol dehydrogenase-1B (ADH1B, previously called ADH2), and ADH1C (previously called ADH3) affect the metabolism of alcohol. The inactive ALDH2 encoded by ALDH2*1/*2 and the less-active ADH1B encoded by ADH1B*1/*1 increase the risk of esophageal squamous cell carcinoma in East Asian drinkers. This case-control study involved 96 Japanese men with oral and pharyngeal squamous cell carcinoma (hypopharyngeal cancer in 43 patients and oral/oropharyngeal cancer in 53) and 642 cancer-free Japanese men. The risk of the cancers overall and of hypopharyngeal cancer was increased 3.61- and 10.08-fold, respectively, by ALDH2*1/*2 among moderate-to-heavy drinkers (9+ units/week; one unit = 22 g of ethanol), but the risk of oral/oropharyngeal cancer was not significantly affected by the ALDH2 genotype. The results obtained with a simple alcohol flushing questionnaire were essentially comparable with those obtained by ALDH2 genotyping. Among moderate-to-heavy drinkers, men with the less-active ADH1B*1/*1 had a significantly higher risk of the cancers overall, of hypopharyngeal cancer, and of oral/oropharyngeal cancer (OR = 5.56, 7.21 and 4.24, respectively). In view of the linkage disequilibrium between ADH1B and ADH1C, the ADH1C genotype does not significantly affect cancer risk. The significant independent risk factors for oral and pharyngeal cancer overall among moderate-to-heavy drinkers were inactive ALDH2*1/*2, less-active ADH1B*1/*1, frequent drinking of strong alcohol beverages straight, smoking, and lower intake of green-yellow vegetables. Educating these risks for cancer of the upper aerodigestive tract could be a useful new strategic approach to the prevention of these cancers in Japanese.     

Relationship between alcohol drinking, ADH2 and ALDH2 genotypes, and risk for hepatocellular carcinoma in Japanese

The polymorphism in the ALDH2 gene plays a central role in Asian alcohol hypersensitivity and has been associated with the risk for esophageal cancer. In the present study, we attempted to examine associations between the ADH2 and ALDH2 polymorphisms, alcohol drinking and hepatocellular carcinoma (HCC) development in a case-control study in Japan. One hundred and two patients with HCC (85 males and 17 females) and 125 control subjects (101 males and 24 females) were enrolled in the study. Higher cumulative amounts of alcohol consumption (drink-years of > or = 40 drinks/day x year) showed a significant association with HCC development (odds ratio, OR = 2.7; 95% CI = 1.3-5.5, adjusted for age and smoking). By contrast, we could find no association of the ALDH2 genotypes with HCC development (adjusted OR for ALDH2*1/*2 = 1.1; 95% CI = 0.6-2.1). Likewise, the ADH2 genotypes were not associated with HCC development (adjusted OR for ADH2*2/*2 = 0.8; 95% CI = 0.5-1.5). The present results do not support a contribution of acetaldehyde, an active metabolite of ethanol, to HCC development and rather indicate a direct involvement of ethanol in hepatocarcinogenesis.     

Development of squamous neoplasia in esophageal iodine-unstained lesions and the alcohol and aldehyde dehydrogenase genotypes of Japanese alcoholic men

We investigated the development of esophageal neoplasia in biopsy specimens of the distinct iodine-unstained lesions (DIULs) ≥ 5 mm detected in 280 of 2,115 Japanese alcoholic men who underwent screening by esophageal iodine staining. Low-grade intraepithelial neoplasia (LGIN) was diagnosed in 155 of them, high-grade intraepithelial neoplasia (HGIN) in 57, and invasive SCC in 35. The size of the DIULs increased with the degree of neoplasia. Most LGINs were flat and were missed before iodine staining. Some DIULs became a light pink color (PC) about 2 min after staining, and 2.6, 56.1 and 96.0% of the LGIN, HGIN and invasive SCC lesions, respectively, were PC-sign-positive. Multiple DIULs of any size markedly increased the risk of LGIN [adjusted OR (95%CI) = 10.1 (7.12-14.5)], HGIN [27.9 (14.6-53.4)] and invasive SCC [21.6 (10.1-46.4)], and were strongly associated with the presence vs. absence of DIULs ≥ 5 mm [13.3 (9.21-19.1)], inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/*2) vs. ALDH2*1/*1 [2.60 (1.79-3.78)], and less-active alcohol dehydrogenase-1B (ADH1B*1/*1) vs. ADH1B*2 allele [2.61 (1.87-3.64)]. The combination of ALDH2*1/*2 and ADH1B*1/*1 synergistically increased the risk of LGIN [4.53 (2.17-9.47)], HGIN [10.4 (4.34-24.7)] and invasive SCC [21.7 (7.96-59.3)]. Esophageal neoplasia developed at earlier ages in those with ALDH2*1/*2. Biopsy-proven HGIN was diagnosed as invasive SCC in 15 (39.5%) of 38 patients after endoscopic mucosectomy or surgery. In conclusion, large size, non-flat appearance, positive PC sign and multiplicity of DIULs and ALDH2*1/*2 and ADH1B*1/*1 were associated with development of esophageal neoplasia in Japanese alcoholics. Biopsy-proven HGIN should be totally resected for both diagnostic and therapeutic purposes.     

Lifestyle habits and genetic susceptibility and the risk of esophageal cancer in the Thai population

The association of lifestyle habits and polymorphism of ADH2 and ALDH2 genes with the risk of esophageal cancer in Thai population was investigated in a hospital-based case-control study: 202 cases and 261 controls. The results of multivariate logistic analysis showed that alcohol consumption >60g/day, smoking >10 cigarettes/day and chewing betel >or=10 quids/day significantly increased risk (odds ratio (OR) 5.84, 95% confidence interval (CI) 3.15-10.83; 4.65, 95% CI 1.99-10.84; and 4.68, 95% CI 2.05-10.72, respectively). ADH2*1/*1 also increased the risk significantly (OR 1.56, 95% CI 1.01-2.39) while ALDH2 did not (OR of ALDH2*1/*2 1.57, 95% CI 0.89-2.76). However, the combined at risk genotypes, ADH2*1/*1 and ALDH2*1/*2 increased risk to four-fold. In addition, significant gene-environment interaction was found. Heavy drinkers >60g/d harboring ADH2*1/*1 or ALDH2*1/*2 had about an 11-fold increased risk.     

Influence of alcohol consumption and gene polymorphisms of ADH2 and ALDH2 on hepatocellular carcinoma in a Japanese population

Although alcohol intake as well as hepatitis viruses has been associated with hepatocellular carcinoma (HCC), gene-alcohol interactions on HCC risk remain to be elucidated. We conducted a case-control study to examine whether polymorphisms of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) modified the HCC risk depending on the amount of alcohol intake. ADH2 and ALDH2 genotyping was performed by a duplex polymerase chain reaction with confronting two-pair primers in 209 newly diagnosed HCC cases and 2 different controls [275 hospital controls and 381 patients with chronic liver disease (CLD)]. Multiple logistic regression analyses revealed that heavy drinkers consuming >or=3 "go"s/day of sake (69 g of ethanol/day) showed an increased risk of HCC based on comparison of HCC cases with hospital controls [adjusted odds ratio (OR) = 13.5; 95% confidence interval (CI) 3.3-54.3] or CLD patients (adjusted OR = 7.0; 95% CI 2.5-19.2), whereas the overall risk was not elevated among light to moderate drinkers consuming <3 "go"s/day. Interestingly, light to moderate drinking was associated with an increased risk among those with ALDH2*1/*2 (adjusted OR = 4.5 or 2.0), but not among those with ALDH2*1/*1 (adjusted OR = 0.8 or 1.0; p interaction = 0.03 or 0.13). However, this gene-alcohol interaction was not observed for heavy drinking. Among light to moderate drinkers, people with the combination of ALDH2*1/*2 and ADH2*2/*2 revealed the highest risk of HCC. These findings indicate that the ALDH2 polymorphism may modify HCC risk among light to moderate drinkers.     

Alcohol dehydrogenase-2 and aldehyde dehydrogenase-2 genotypes, alcohol drinking and the risk of primary hepatocellular carcinoma in a chinese population.

Objective: To investigate the relationship of alcohol dehydrogenase-2 (ADH2) and aldehyde dehydrogenase-2 (ALDH2) genotypes as well as alcohol drinking to the susceptibility of primary hepatocellular carcinoma (HCC). Methods: A case-control study including 208 cases of HCC and 208 controls matched with sex, age and residential area was carried out in Taixing city of Jiangsu province, China. Blood samples were collected and tested for ADH2 and ALDH2 genotypes by PCR-RFLP method. Results: There were no significant differences in the frequency of either ADH2 or ALDH2 genotypes between cases and controls. Compared with no-drinkers possessing ALDH21*1 genotypes, drinkers with ALDH21*2 or ALDH22*2 genotypes and cumulative amount of alcohol consumption >3 (Kg * years) were at a significantly higher risk of developing HCC (OR=3.30, 95%CI: 1.24-8.83). In contrast, there was no significant difference in cancer risk between no-drinkers with ADH21*1 and drinkers with ADH2 1*2 or ADH22*2 genotypes. A dose-dependent positive result was found (P=0.044) between cumulative amount of alcohol consumption and the risk of HCC in individuals carrying ALDH21*2 or ALDH22*2 genotypes. Drinkers with cumulative amount of alcohol consumption >3 (Kg * years) who possessed both inactive ALDH2 (ALDH21*2 or ALDH22*2) and inactive ADH (ADH21*2 or ADH22*2) genotypes were not at a significantly higher risk of HCC (adjusted OR=4.26, 95%CI: 0.63-29.08) compared to no-drinkers possessing ADH21*1 and ALDH21*1 genotypes. Compared with individuals possessing ALDH21*1, with negative HBsAg and cumulative amount of alcohol consumption 3 (Kg * years) had a significantly higher risk of HCC (OR=49.71, 95%CI: 5.51-448.96). Conclusion: These results revealed that it was not ADH2 but ALDH2 polymorphisms that had a significant interaction with heavy alcohol consumption in the development of HCC. This result suggests that to help lower their risk for HCC , persons with ALDH21*2 or ALDH22*2 genotypes should be encouraged to reduce their consumption of alcoholic beverages.     

Alcohol Dehydrogenase-2 and Aldehyde Dehydrogenase-2 Genotypes,Alcohol Drinking and the Risk for Stomach Cancer in Chinese Males

Objective: To investigate the relationship among alcohol dehydrogenase-2 (ADH2) and aldehyde dehydrogenase-2 (ALDH2) genetic polymorphisms, alcohol consumption, and the susceptibility of stomach cancer in Chinese males. Methods: Three hundred and eighty-two stomach cancer patients and 382 healthy controls from Taixing and Changshu city of Jiangsu province were enrolled in this study. ADH2 and ALDH2 genotypes were examined by PCR and denaturing high-performance liquid chromatography (DHPLC). Unconditional logistic regression was used to calculate the odds ratios (OR) and 95% confidence intervals (95% CI). Results: (1) In no drinkers, compared with ALDH2G/G carriers, ALDH2 G/A (OR=1.67, 95%CI: 1.01-2.78) carriers showed a significantly elevated risk of developing stomach cancer. No association was found between ADH2 genotypes and risk of stomach cancer. (2) ALDH2 A allele carriers with cumulative amount of alcohol consumption ≥2.5 (Kg * years) were at a higher risk of developing stomach cancer compared with those with cumulative amount of alcohol consumption <2.5Kg (Kg * years) (OR=2.72, 95%CI:0.89-8.31) and ALDH2 G/G carriers with cumulative amount of alcohol consumption <2.5 (Kg * years) (OR=2.46, 95%CI=0.90-6.72) or ≥2.5 (Kg * years) (OR=2.53, 95%CI=0.86-7.49). (3) Compared with individuals with ADH2 A/A and ALDH2 G/G genotypes, ADH2 G and ALDH2 A allele carriers were not at a high risk of developing stomach cancer, with regard to the status of alcohol consumption, and even cumulative amount of alcohol consumption ≥1.5 (Kg * years) (OR =1.65, 95%CI:0.56-4.82). Conclusion: ADH2 and ALDH2 polymorphisms and alcohol drinking may not play an important role in the development of stomach cancer in Chinese males.     

ADH1B and ALDH2 polymorphisms and their associations with increased risk of squamous cell carcinoma of the head and neck in the Korean population

Alcohol consumption is a major risk factor for squamous cell carcinoma of the head and neck (SCCHN). Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are key enzymes in ethanol metabolism. The objective of this study was to investigate the relationships of ADH and ALDH single nucleotide polymorphisms (SNPs) with the risk of developing SCCHN in a Korean sample. We genotyped ADH1B +3170A>G (rs1229984) and ALDH2 +1951G>A (rs671) SNPs in 225 Korean SCCHN patients and 301 healthy controls by single base extension and TaqMan assay. The frequencies of the ADH1B +3170A>G (*2*2/*2*1/*1*1) genotypes were 48.0%/38.7%/13.3% in SCCHN patients, and 57.8%/37.2%/5.0% in controls, respectively. The odds ratio (OR) and 95% confidence interval of the ADH1B*1*1 genotype was 1.89 (1.23-2.92) relative to the *2*2 genotype. The frequencies of the ALDH2 +1951G>A (*1*1/*1*2/*2*2) genotypes were 67.6%/31.6%/0.9% in SCCHN patients, and 67.8%/29.6%/2.7% in controls, respectively. In subgroup analyses according to smoking and alcohol drinking status, the OR of the ADH1B*1*1 genotype was increased in the heavy drinker group [8.85 (1.095-40.0)] and in the heavy smoker group [4.7 (1.54-14.29)]. We conclude that the ADH1B*1*1 genotype is associated with an increased risk of SCCHN, especially in heavy drinkers and heavy smokers. This genotype could be a useful biomarker for identifying Koreans with a greater risk of SCCHN.     

Risk of squamous cell carcinoma of the upper aerodigestive tract in cancer-free alcoholic Japanese men: an endoscopic follow-up study.

Asian case-control studies have shown a strong relationship between the development of squamous cell carcinoma (SCC) of the esophagus and alcohol consumption combined with inactive aldehyde dehydrogenase-2 (ALDH2*1/*2), less-active alcohol dehydrogenase-1B (ADH1B*1/*1), high mean corpuscular volume (MCV), and self-reported facial flushing in response to alcohol. However, little is known about whether these risk factors prospectively influence cancer development in cancer-free alcoholics. Between 1993 and 2005, 808 Japanese alcoholic men diagnosed as cancer-free by an initial endoscopic screening examination received follow-up examinations ranging from 1 to 148 months (median, 31 months) later, and SCC of the upper aerodigestive tract was diagnosed in 53 of them (esophagus in 33 and oropharyngolarynx in 30). Cox proportional hazards analysis showed that the age-adjusted relative hazard for SCC was 11.55 [95% confidence interval (95% CI), 5.73-23.3] in ALDH2*1/*2 heterozygotes compared with ALDH2*1/*1 homozygotes, 2.02 (95% CI, 1.02-4.02) in ADH1B*1/*1 homozygotes compared with ADH1B*1/*2 heterozygotes or *2/*2 homozygotes, 2.64 (95% CI, 1.49-4.67) in patients with flushing compared with those who had never experienced flushing, 2.91 (95% CI, 1.63-5.20) in those with an MCV >or= 106 compared with those with an MCV < 106, 2.52 (95% CI, 1.22-5.22) in those who smoked >or=30 cigarettes per day compared with those who smoked 0 to 19 cigarettes per day, 7.26 (95% CI, 3.99-13.23) in those with esophageal dysplasia compared with those without distinct iodine-unstained lesions >or=5 mm, and 0.28 (95% CI, 0.09-0.85) in those with body mass index >or= 23.2 (highest quartile) compared with those with body mass index < 19.0 (lowest quartile). These predictors are useful for selecting appropriately patients for careful follow-up examinations.     

Alcohol and aldehyde dehydrogenase gene polymorphisms and oropharyngolaryngeal, esophageal and stomach cancers in Japanese alcoholics

Alcohol dehydrogenase-2 (ADH2) and aldehyde dehydrogenase-2 (ALDH2) gene polymorphisms play roles in ethanol metabolism, drinking behavior and esophageal carcinogenesis in Japanese; however, the combined influence of ADH2 and ALDH2 genotypes on other aerodigestive tract cancers have not been investigated. ADH2/ALDH2 genotyping was performed on lymphocyte DNA samples from Japanese alcoholic men (526 cancer-free; 159 with solitary or multiple aerodigestive tract cancers, including 33 oropharyngolaryngeal, 112 esophageal, 38 stomach and 22 multiple primary cancers in two or three organs). After adjustment for age, drinking and smoking habits, and ADH2/ALDH2 genotypes, the presence of either ADH2*1/2*1 or ALDH2*1/2*2 significantly increased the risk for oropharyngolaryngeal cancer [odds ratios (ORs), 6.68 with ADH2*1/2*1 and 18.52 with ALDH2*1/2*2] and esophageal cancer (ORs, 2.64 and 13.50, respectively). For patients with both ADH2*1/2*1 and ALDH2*1/2*2, the risks for oropharyngolaryngeal and esophageal cancers were enhanced in a multiplicative fashion (OR = 121.77 and 40.40, respectively). A positive association with ALDH2*1/2*2 alone was observed for stomach cancer patients who also had oropharyngolaryngeal and/or esophageal cancer (OR = 110.58), but it was not observed for those with stomach cancer alone. Furthermore, in the presence of ALDH2*1/2*2, the risks for multiple intra-esophageal cancers (OR = 3.43) and for esophageal cancer with oropharyngolaryngeal and/or stomach cancer (OR = 3.95) were higher than the risks for solitary intra-esophageal cancer and for esophageal cancer alone, but these tendencies were not observed for ADH2*1/2*1 genotype. Alcoholics' population attributable risks due to ADH2/ALDH2 polymorphisms were estimated to be 82.0% for oropharyngolaryngeal cancer and 63.9% for esophageal cancer.     

Contribution of the alcohol dehydrogenase-1B genotype and oral microorganisms to high salivary acetaldehyde concentrations in Japanese alcoholic men

The less-active homozygous alcohol dehydrogenase-1B (ADH1B*1/*1) and inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/*2) increase the risk of upper aerodigestive tract cancer (UADTC) in Japanese alcoholics. We evaluated associations between ADH1B/ALDH2 genotypes and the blood and salivary ethanol/acetaldehyde levels of 80 Japanese alcoholic men in the morning when they first visited our hospital after drinking the day before. Higher levels of ethanol persisted in the blood for longer periods in ADH1B*1/*1 carriers (n = 25) than in ADH1B*2 allele carriers after adjustment for the amount and time of the preceding alcohol consumption and body weight [median (25th-75th %): 20.5 mM (15.5-52.4) vs. below detection level (相似文献   

乙醇脱氢酶2和乙醛脱氢酶2基因多态性及饮酒习惯与直肠癌易感性的研究

目的:研究乙醇脱氢酶2(ADH2)、乙醛脱氢酶2(ALDH2)基因多态性与直肠癌易感性的关系。方法:采用病例-对照研究方法,以PCR-DH-PLC检测研究对象的ADH2/ALDH2基因型,比较不同的基因型及生活习惯与直肠癌的关系。结果:1)与不饮酒者相比较,饮酒者患直肠癌的危险性显著增高(OR=2.20,95%CI:1.47～3.28,P=0.000);2)多因素分析结果未发现ADH2、ALDH2各基因型与直肠癌的危险性有关。3)对ADH2、ALDH2基因多态相互作用的分层分析发现,同时携带ADH2A/A和ALDH2G/G基因型者,发生直肠癌的危险性显著增高(性别、年龄和吸烟调整OR=1.82,95%CI:1.07～3.09)。4)在饮酒者中,ADH2A/A、A/G G/G基因型者患直肠癌的调整OR分别为2.56(95%CI:1.38～4.73)和2.10(95%CI:1.15～3.84);ALDH2G/G基因型者发生直肠癌的调整OR为1.82(95%CI:1.07～3.09)。结论:饮酒是直肠癌的危险因素;ADH2A/A与ALDH2G/G基因型在增加直肠癌易感性上有协同作用;ALDH2G/A A/A基因型可减弱饮酒患直肠癌的危险性。     

Esophageal Cancer Risk by ALDH2 and ADH2 polymorphisms and Alcohol Consumption: Exploration of Gene-Environment and Gene-Gene Interactions

Alcohol drinking is a major risk factor for esophageal cancer in Japan and its impact may be modulated by levels ‍of ALDH2, ADH2 and CYP2E1, three representative alcohol-metabolizing enzymes which display genetic ‍polymorphisms altering individual alcohol-oxidizing capacity and drinking behavior. To assess the actual influence ‍of ADH2 Arg47His, ALDH2 Glu487Lys and CYP2E1 variant c2 allele polymorphisms on esophageal cancer risk ‍with conjunction with alcoholic consumption, the present 1:3 matched case-control study was conducted. The 165 ‍histologically diagnosed Japanese esophageal cancer cases were here compared with 495 randomly selected controls, ‍matched with respect to sex and age. Conditional logistic regression was used to calculated Odds Ratios (ORs) and ‍95% confidence intervals (95% CI). Significant gene-environment interactions between alcohol drinking and both ‍ADH2 and ALDH2 were observed regarding esophageal cancer risk. The ADH2 Arg47His polymorphism showed ‍moderately increased risk (OR for Arg/His and Arg/Arg relative to His/His: 2.01 (1.39-2.90)). In the ALDH2 case, ‍comparing the Glu/Lys with the Glu/Glu genotype, ORs were markedly increased to 9.64 (3.23-28.8) and 95.4 (28.7- ‍317) from 1.88 (0.42-8.37) and 4.62 (0.93-23.1) for moderate drinking and heavy drinking, respectively. No significant ‍alteration in risk was observed with the CYP2E1 polymorphism. In conclusion, the present study revealed a significant ‍gene-environment interaction between alcohol drinking and the ALDH2 polymorphism regarding esophageal cancer ‍risk among a general population in Japan, providing concrete evidence of a role for acetaldehyde in neoplastic ‍development. Interactions between ALDH2 and ADH2 need further clarification.‍ ‍     

Macrocytosis,a new predictor for esophageal squamous cell carcinoma in Japanese alcoholic men

Early esophageal squamous cell carcinoma detected by esophageal iodine staining can be easily treated by endoscopic mucosectomy, and identifying its predictors is important in better selecting candidates to screen for this high-mortality cancer. The common etiologies of elevated mean corpuscular volume (MCV) and esophageal cancer, including folate deficiency, smoking, drinking and high acetaldehyde exposure, suggest testing MCV as such a predictor. Japanese alcoholic men with (n = 65) and without (n = 206) esophageal squamous cell carcinomas, excluding those with liver cirrhosis, were assessed for MCV within 7 days of their last drink, alone or in combination with findings from either the alcohol flushing questionnaire or genotyping to identify inactive aldehyde dehydrogenase-2 (ALDH2*1/2*2) and the less-active form of alcohol dehydrogenase-2 (ADH2*1/2*1), which pose risks for esophageal squamous cell carcinoma. MCV was higher in cancer patients than in the control group. MCV was higher in both groups in those who were heavier smokers, had lower body mass index (BMI), experienced alcohol flushing, and had ALDH2*1/2*2. After adjusting for age, drinking and smoking habits, BMI and ALDH2/ADH2 genotypes, macrocytosis of MCV > or =106 fl was associated with increased risk for esophageal cancer (OR = 2.75). Men with both MCV > or =106 fl and alcohol flushing had an even higher cancer risk (OR = 5.51). The combinations of MCV > or =106 fl with ALDH2*1/2*2 or ADH2*1/2*1 alone, and both ALDH2*1/2*2 and ADH2*1/2*1 (ORs = 11.44, 21.22 and 319.7, respectively) showed consistently higher risk than the corresponding group with MCV <106 fl (ORs = 7.24, 4.71 and 27.01, respectively). In conclusion, MCV measurement, alone or in combination with the markers of alcohol sensitivity, provides a new means of predicting risk for esophageal squamous cell carcinoma in Japanese alcoholic men.     

Gene-gene and gene-environment interactions between alcohol drinking habit and polymorphisms in alcohol-metabolizing enzyme genes and the risk of head and neck cancer in Japan

Alcohol consumption is a strong risk factor for squamous cell carcinoma of the head and neck (SCCHN). The genetic polymorphisms aldehyde dehydrogenase2 (ALDH2) Glu487Lys and alcohol dehydrogenase 2 (ADH2) His47Arg, which have a strong impact on alcohol metabolism, are common in the Japanese population. To clarify the significance of these polymorphisms in SCCHN carcinogenesis, we conducted a matched case-control study with 239 incident SCCHN subjects and 716 non-cancer controls. Both ADH2 Arg/Arg and ALDH2 Glu/Lys were found to be independently associated with increased risk, with odds ratios (OR) of 2.67 (95% confidence interval [CI] 1.51-4.57) and 1.66 (95% CI 1.20-2.31), respectively. Further, compared with subjects having both ADH2 His/His and ALDH2 Glu/Glu, the adjusted OR and its 95% CI for those with both ADH2 Arg/Arg and ALDH2 Glu/Lys was 5.00 (2.32-10.71) in all subjects. This combination effect was evident in heavy drinkers (OR 11.3, 95% CI 2.97-43.3) but not in moderate or non-drinkers. Statistically significant gene-environment interactions between the two polymorphisms and drinking level were seen (ADH2 P = 0.035, ALDH2, P = 0.013). Furthermore, we also found a statistically significant gene-gene interaction between the two polymorphisms (P = 0.042). In conclusion, this case-control study showed a significantly increased risk of SCCHN in subjects with the ADH2 Arg/Arg and ALDH2 Glu/Lys polymorphisms in a Japanese population. In addition, our results also demonstrated that this risk was associated with significant gene-gene interactions between ADH2 and ALDH2 polymorphisms, as well as gene-environment interactions between these polymorphisms and alcohol drinking.     

Oral squamous cell cancer risk in relation to alcohol consumption and alcohol dehydrogenase-3 genotypes.

Heavy alcohol consumption, particularly in combination with cigarette smoking, increases the risk of oral squamous cell carcinoma (OSCC). Alcohol dehydrogenase 3 (ADH3) converts ethanol to acetaldehyde, which is a suspected oral carcinogen. The ADH3*1 allele is associated with increased conversion of ethanol to acetaldehyde, but whether the risk of OSCC is increased among ADH3*1 carriers, or whether the risk of OSCC attributable to alcohol consumption is modified by ADH3 genotype is unclear from previous studies. We examined the association between ADH3 genotypes, alcohol consumption, and OSCC risk in a population-based study of 333 cases and 541 controls from the state of Washington. The distribution of ADH3 genotypes was similar among cases and controls: ADH3*1/*1: 32.7% cases, 36.5% controls; ADH3*1/*2: 49.0% cases, 43.1% controls: ADH3*2/*2: 18.3% cases, 20.3% controls. The age-, sex-, and race-adjusted odds ratios (OR), relative to ADH3*2/*2 carriers, were as follows: ADH*1/*1: OR, 1.0 [95% confidence interval (CI) = 0.7, 1.5]; and ADH3*1/*2: OR, 1.3 (95% CI = 1.0, 1.8). We modeled the risk of OSCC associated with alcohol consumption as modified by ADH3 genotype adjusting for age, sex, race, and cigarette smoking. Among ADH3*2 homozygotes, the risk of OSCC increased 5.3% (2.1-8.5%) with each additional alcoholic drink/week, compared with 2.5% (1.5-2.6%) and 1.2% (0.0-2.4%) among persons carrying the ADH3*1/*2 and ADH3*1/*1 genotypes, respectively. These data suggest that the ADH3*2 allele confers increased susceptibility to the effect of alcohol on OSCC risk in our population.     

ADH1B,ALDH2, GSTM1 and GSTT1 Gene Polymorphic Frequencies among Alcoholics and Controls in the Arcadian Population of Central India

Background: Epidemiological research has highlighted the global burden of primary liver cancer cases due toalcohol consumption, even in a low consumption country like India. Alcohol detoxification is governed by ADH1B,ALDH2, GSTM1 and GSTT1 genes that encode functional enzymes which are coordinated with each other to removehighly toxic metabolites i.e. acetaldehyde as well as reactive oxygen species generated through detoxification processes.Some communities in the population appears to be at greater risk for development of the liver cancer due to geneticpredispositions. Methods: The aim of this study was to screen the arcadian population of central India in order toinvestigate and compare the genotype distribution and allele frequencies of alcohol metabolizing genes (ADH1B,ALDH2, GSTM1 and GSTT1) in both alcoholic (N=121) and control (N=145) healthy subjects. The gene polymorphismanalysis was conducted using PCR and RFLP methods. Results: The allele frequency of ALDH2 *1 was 0.79 and ofALDH2*2 was 0.21 (OR:1.12; CI (95%): 0.74-1.71). The null allele frequency for GSTM1 was 0.28 (OR:0.85; CI(95%): 0.50-1.46) and for GSTT1 was 0.20 (OR:1.93; CI (95%): 1.05-3.55). No gene polymorphism for ADH1B wasnot observed. The total prevalence of polymorphisms was 3.38% for ALDH2, GSTM1 and GSTT1. Conclusion: Theresults of this study suggested that individuals of the Central India population under study are at risk for liver disordersdue to ALDH2, GSTM1 and GSTT1 gene polymorphisms. This results may have significance for prevention of alcoholdependence, alcoholic liver disorders and the likelihood of liver cancer.