The Clinical Relevance of the Expression of SGLT2 in Lung Adenocarcinoma.

PURPOSE: We aimed to elucidate the functions and clinical relevance of sodium-glucose cotransporter 2 (SGLT2) in resected lung adenocarcinoma. METHODS: The protein expression of SGLT2 in tumor samples from 199 patients with lung adenocarcinoma was analyzed by immunohistochemistry, and the protein expression, clinical variables, and survival outcomes were compared. RESULTS: The median SGLT2 expression was significantly higher in advanced-stage and more aggressive adenocarcinomas. Age ≥70 (p < 0.01), BI ≥600 (p < 0.01), PRDX4 <25 (p < 0.01), and SGLT2 ≥12% (p = 0.03) were significant factors for RFS in multivariate analysis. Significant differences were observed in the RFS rates of the groups divided using the cutoff value of SGLT2 ≥12% (5-year RFS: 72.6% vs. 90%) (p < 0.01). CONCLUSION: The expression of SGLT2 was more frequently detected in advanced-stage and more aggressive adenocarcinomas with aggressive biological behavior than in their counterparts. The survival analysis revealed that the strong expression of SGLT2 was associated with poorer RFS. The SGLT2 expression predicts postoperative recurrence in lung adenocarcinoma patients.

The effect of ethanol on the formation of N2-ethylidene-dG adducts in mice: implications for alcohol-related carcinogenicity of the oral cavity and esophagus.

The present study aimed to experimentally confirm that long-term alcohol drinking causes a high risk of oral and esophageal cancer in aldehyde dehydrogenase 2 (ALDH2)-deficient individuals. Aldh2 knockout mice, an animal model of ALDH2-deficiency, were treated with 8% ethanol for 14 months. Levels of acetaldehyde-derived DNA adducts were increased in esophagus, tongue and submandibular gland. Our finding that a lack of Aldh2 leads to more DNA damage after chronic ethanol treatment in mice supports epidemiological findings on the carcinogenicity of alcohol in ALDH2-deficient individuals who drink chronically.

Triple-negative expression (ALDH1A1-/CD133-/mutant p53-) cases in lung adenocarcinoma had a good prognosis.

Cancer stem cells (CSCs) are major contributors to the malignant transformation of cells because of their capacity for self-renewal. Aldehyde dehydrogenase1A1 (ALDH1A1) and CD133 are promising candidate of CSC markers in non-small cell lung cancer (NSCLC). Furthermore, TP53 is frequently mutated in lung cancer, and the loss of its function is associated with malignant characteristics. However, the relationship between CSCs and mutant p53 in lung adenocarcinoma is not well-established. We examined the expression of ALDH1A1, CD133, and mutant p53 in lung adenocarcinoma patients and conducted a clinicopathological study. Triple-negative cases without ALDH1A1, CD133, and mutant p53 expression in lung adenocarcinoma were shown to have a much better prognosis than others. Our present results suggest that detection of CSC markers and mutant p53 by immunohistochemical staining may be effective in therapeutic strategies for lung adenocarcinoma.

Monocarboxylate transporters 1 and 4 are involved in the invasion activity of human lung cancer cells.

Cancer cells show constitutive upregulation of glycolysis, and the concentration of lactate thus produced correlates with prognosis. Here, we examined whether lactate concentration and lactate transporter expression are related to migration and invasion activity. We found that the expression of the monocarboxylate transporters MCT1 and MCT4, but not MCT5, in human lung cancer cell lines was significantly correlated with invasiveness. To clarify the effects of MCT1 and MCT4 expression on invasion, we performed migration and invasion assays after transfection with siRNA specific for MCT1 or MCT4. Knockdown of MCT1 or MCT4 did not influence cell migration but reduced invasion; this was also observed for knockdown of the lactate transporter-associated protein basigin. We also demonstrated that both expression and activity of MMP9 and MMP2 were not correlated with invasion activity and not regulated by MCT1, MCT4 and basigin. Furthermore, the addition of lactate did not increase migration and invasion activity, but low concentration of 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), a general anion channel blocker, as well as other MCT inhibitors quercetin and simvastatin, inhibited cell invasion without influencing migration activity and the cellular expression of MCT1 and MCT4. This is the first report suggesting that lactate transporters are involved in human cancer cell invasiveness. As such, these proteins may be promising targets for the prevention of cancer invasion and metastasis.

Paraneoplastic limbic encephalitis due to lung squamous cell carcinoma.

Paraneoplastic limbic encephalitis (PLE) is one of paraneoplastic neurological syndrome (PNS). We herein report a case of PLE due to lung squamous cell carcinoma. A 80-year-old woman visited because of several neurological symptoms. Brain magnetic resonance imaging revealed hyperintense signals at the splenium of the corpus callosum, suggesting limbic encephalitis. Chest X-ray and computed tomography showed a 17 × 14 mm tumor in the left lung field, suggesting lung cancer. Surgical examination revealed T1bN0M0 lung squamous cell carcinoma. She died 50 days after surgery due to the rapid progression of encephalitis. PLE is an extremely rare disorder, and even a case in the early stage of cancer shows poor prognosis. We should doubt a possibility of PLE, and detailed brain examination should be performed in case of consciousness disorder with rapid progression in the cancer patient.

Association Between CD133 Expression and Prognosis in Human Lung Adenocarcinoma.

BACKGROUND/AIM: CD133 is a promising candidate marker for cancer stem cells. However, clinical studies on CD133 expression in human lung adenocarcinoma have not yet been conducted. We hypothesized that CD133 expression in lung adenocarcinoma is a poor prognostic factor. PATIENTS AND METHODS: CD133 expression in lung adenocarcinoma was examined clinicopathologically. Then, clinicopathological parameters and patient prognosis were investigated. Moreover, CD133 expression was examined via immunohistochemical staining, and the relationship between CD133 expression and clinicopathological parameters was explored. RESULTS: Approximately 48.0% (49/102) of patients had CD133-positive cells. Based on a subgroup analysis, the CD133-positive group with pStage I+II disease had a significantly worse disease-free interval than the CD133-negative group (p<0.05). CONCLUSION: CD133 expression may be a poor prognostic factor in lung adenocarcinoma.

Application of tryptophan fluorescence to assess sensitizing potentials of chemicals.

There are too many chemical substances around our living space. However, the toxicity of most of them has not been reported, especially regarding their sensitizing potentials. We aimed to develop a simple in vitro method to quantitatively predict the sensitizing potentials of chemicals by measuring the fluorescence of chemical-human serum albumin (HSA) complexes. HSA was treated with test chemicals and then analyzed by tryptophan fluorescence and protein concentration measurement. Four commonly designated sensitizers, two possible sensitizers, and two nonsensitizers were examined using the tryptophan fluorescence assay. HSA fluorescence at 280 nm excitation and 340 nm emission was reduced by toluene 2,4-diisocyanate (TDI), dose dependently. The addition of TDI immediately reduced the fluorescence, and it was stable for 6 h to 21 days after treatment, with a slight decrease. The reduction of HSA fluorescence by chemicals was in the order: commonly designated sensitizers > possible sensitizers > nonsensitizers. Chemical treatment at 0.05 and 0.5 mM led to optimal separation among the three groups. o-Phthalaldehyde (OPA), which has not been evaluated regarding its sensitization potential by any of the authorized organizations, reduced HSA fluorescence as much as the commonly designated sensitizer at final concentrations of the chemical of 0.05 and 0.5 mM. According to our method, OPA is evaluated as a commonly designated sensitizer. The treatment of all test chemicals did not lead to marked differences in the total protein concentrations by either the Lowry or the Bradford method. The assay utilizing tryptophan fluorescence loss of HSA after chemical treatment is a promising method to evaluate the sensitizing potentials of chemicals.

Characteristics of aldehyde dehydrogenase 2 (Aldh2) knockout mice.

Acetaldehyde is an intermediate of ethanol oxidation. It covalently binds to DNA, and is known as a carcinogen. Aldehyde dehydrogenase 2 (ALDH2) is an important enzyme that oxidizes acetaldehyde. Approximately 45% of Chinese and Japanese individuals have the inactive ALDH2 genotypes (ALDH2*2/*2 and ALDH2*1/*2), and Aldh2 knockout mice appear to be a valid animal model for humans with inactive ALDH2. This review gives an overview of published studies on Aldh2 knockout mice, which were treated with ethanol or acetaldehyde. According to these studies, it was found that Aldh2 -/- mice (Aldh2 knockout mice) are more susceptible to ethanol and acetaldehyde-induced toxicity than Aldh2 +/+ mice (wild type mice). When mice were fed with ethanol, the mortality was increased. When they were exposed to atmospheres containing acetaldehyde, the Aldh2 -/- mice showed more severe toxic symptoms, like weight loss and higher blood acetaldehyde levels, as compared with the Aldh2 +/+ mice. Thus, ethanol and acetaldehyde treatment affects Aldh2 knockout mice more than wild type mice. Based on these findings, it is suggested that ethanol consumption and acetaldehyde inhalation are inferred to pose a higher risk to ALDH2-inactive humans. These results also support that ALDH2-deficient humans who habitually consume alcohol have a higher rate of cancer than humans with functional ALDH2.

Expression of cytochrome P450 in non-small cell lung cancer.

Lung cancer accounts for most of cancer-related deaths in both men and women. Lung cancer is also associated with cigarette smoking that exposes the individual to carcinogenic chemicals. Normally, CYP enzymes (cytochrome P450s) metabolize carcinogens to inactive derivatives, however, occasionally the action of CYP enzymes leads to development of more potent carcinogens. In addition to the metabolism of carcinogenic compounds, CYP enzymes are also involved in the activation and/or inactivation of agents, which are used in the treatment of lung cancer. Therefore, the local level of CYP enzymes in lung cancer and surrounding tissues could be an important determinant in the efficacy of anticancer drugs. Furthermore, the expression of CYP19 (aromatase), estrogen synthesis P450, was found in more than 80 percent of non-small cell lung cancers. Lung cancer was also found to frequently express CYP24A1 that converts 1 alpha, 25-dihydroxyvitamin D3 to its inactive 24-hydroxylated derivatives. The understanding of the local expression of CYP enzymes in tumor tissues is important in the development of better treatment for lung cancer and a standardized treatment, tailor-made, for individual patients.

Significance of immunohistochemical expression of estrogen receptors alpha and beta in squamous cell carcinoma of the esophagus.

PURPOSE: Possible significance of sex hormone estrogen as an antitumor therapeutic arm toward esophageal squamous cell carcinoma (ESCC) cells has been suggested. The aim of the current study was to clarify the clinicopathologic significance of an immunohistochemical expression of estrogen receptors alpha and beta (ER alpha and ER beta) in ESCC. EXPERIMENTAL DESIGN: Expression of ER alpha and ER beta were examined using an immunohistochemical methods in 73 paraffin-embedded sections collected from patients with ESCC who had been subjected to esophageal resection and digestive reconstruction without any preoperative induction therapy. RESULTS: Forty-seven (64.4%) ESCCs had a positive cytoplasmic expression of ER alpha and 21 (28.8%) ESCCs had a positive nuclear expression of ER beta. Univariate analysis showed that both positive ER alpha expression (P=0.0001) and negative ER beta expression (P=0.026) were unfavorable prognostic indicators in ESCC. Moreover, multivariate analysis showed that ER alpha-positive/ER beta-negative expression (P=0.003) and progression of tumor stage (P=0.014) were found to be independent unfavorable prognostic indicators in ESCCs. CONCLUSIONS: Immunohistochemical expression of ER alpha and ER beta were found to be observed in ESCC. Positive expression of ER alpha in addition to negative expression of ER beta proved to be an unfavorable independent prognostic indicator in ESCC.

Methods and rationale for keeping records of hepatitis virus testing in Japanese workplaces.

In Japan, the Ministry of Health, Labour and Welfare issued corporate guidance that employers should recommend their employees to have tests for hepatitis B virus and hepatitis C virus (HV) at least once in their lifetime. However, employers should treat this information as confidential, even though the testing is carried out along with the health examination designated by the Industrial Safety and Health Law. Therefore, the records of HV tests should not be kept by employers, even though records of medical examinations designated by the law must be. This study aimed to clarify the present method for keeping records of HV infection and the rationale in Japanese workplaces. Questionnaires about viral hepatitis were sent to 118 occupational health physicians, and 81 physicians from 100 workplaces responded. The HV test for employees was conducted in 58 workplaces (75.8% of large, 60.4% of bigger medium-sized and 16.7% of smaller medium-sized enterprises). These workplaces were the types of industries where the risk of infecting other persons was low. Subjects of the HV tests were workers who were suspected to have hepatitis virus, and workers who were applicants. Occupational health physicians from most workplaces answered that records of medical examinations designated by law and records of HV tests were not kept separately and shouldn't be. The opinion that the two types of records should not be kept separately appeared to be more from the workplaces where employers or health insurance covered the cost of the HV test. In these cases, the purpose of conducting HV tests at the workplaces was thought to be both promoting welfare of employees and occupational considerations for workers. Occupational health physicians from about 60% of workplaces had misgivings about employees who had hepatitis virus being discriminated against at the workplace if the HV test was included with the required medical examination. Among occupational health physicians from workplaces where occupational health professionals were in charge of the records, there was no standardized rationale for keeping records. However, most workplaces took into consideration the workers' privacy by getting employees' consent before divulging information to their employers. This relied not only on the occupational health professional's or health/safety officer's ethics, but also the necessity of reviewing the purpose and methods of keeping records of HV testing of employees, based on official notices or the Act on the Protection of Personal Information.

Susceptibility to inhalation toxicity of acetaldehyde in Aldh2 knockout mice.

In this study, we evaluated the inhalation toxicity of acetaldehyde in Aldh2 KO (Aldh -/-) mice, using pathological method. Male C57BL/6 (Aldh2 +/+) mice and Aldh -/- mice were exposed to atmospheres containing acetaldehyde at levels of 0, 125, and 500 ppm for 24 h/day during 14 days. Although the average blood acetaldehyde concentration of Aldh -/- mice was higher than that of Aldh2 +/+ mice in the acetaldehyde exposure group, observable effects by the acetaldehyde exposure on the lung and liver were not different between wild type and ALDH2 null mice. In Aldh2 -/- mice, the levels of 1) erosion of respiratory epithelium and the subepithelial hemorrhage in nose, 2) hemorrhage in nasal cavity, 3) degeneration of respiratory epithelium in larynx, pharynx and trachea, and 4) degeneration of dorsal skin were higher compared with Aldh2 +/+ mice, indicating that Aldh2 -/- mice are more acetaldehyde-sensitive than Aldh2 +/+ mice. This is the first example for studying pathological effects of Aldh2 deficiency using Aldh -/- mice exposed to a low level of acetaldehyde.

Cytochrome P450 expression (CYP) in non-small cell lung cancer.

The cytochrome P450 (CYP) is associated with tumor development and progression as well as activation of anti-cancer prodrugs and their metabolic clearance. In this study, we investigated the expression of aryl-hydrocarbon receptor (AH-R) and four CYPs (CYP1A1, CYP2A6, CYP2E1 and CYP3A) as putative diagnostic markers in 78 non-small cell lung cancers (NSCLC) along with clinical features of the patients. In non-small cell lung cancer, the expression of the five markers was mainly observed in adenocarcinoma but not in the most squamous cell cancers. The expression of them in adenocarcinoma was more frequent in females than in males, suggesting that a higher risk of women for developing lung adenocarcinoma might be associated with the frequent expression of AH-R and the CYPs. These factors were also more frequently expressed in early stage adenocarcinoma and more differentiated adenocarcinoma. Multiple types of CYPs are more frequently expressed in early stage of adenocarcinoma than in advanced stage of adenocarcinoma. There were positive relationships among AH-R, CYP1A1, CYP2E1 and CYP3A expressions in adenocarcinoma, which suggests a metabolite-mediated cross talk in the gene regulation of these markers. However, any of them was unrelated with the expression of CYP2A6, suggesting that the gene regulation of CYP2A6 in adenocarcinoma may be different from the other three CYPs. The expression frequency of CYP1A1 and CYP2E1 in tumors is independent of their genetic polymorphism. The survival of the patients with advanced adenocarcinoma expressing more than one of CYPs was lower rate than the patients with those expressing no CYPs, suggesting that the expression of the CYPs in advanced adenocarcinoma may be associated with poor survival. Our results suggest that AH-R and 4 CYPs may be good markers for the determination of quality of lung cancer. The information could be useful for the better management of lung cancer by molecular targeting therapy and selection of anti-cancer drug based on individual spectrum of the marker proteins. Therefore, the spectrum of CYP proteins in lung cancer could be useful for changing the present "order-made" therapy to the "tailor-made" therapy.

Increased cytochrome P450 and aryl hydrocarbon receptor in bronchial epithelium of heavy smokers with non-small cell lung carcinoma carries a poor prognosis.

Smoking induces mutations via the formation of DNA-adducts in the bronchial and alveolar epithelium and contributes to the development of lung cancer. Benz(a)pyrene and nitrosamine, typical carcinogens in cigarette smoke, undergo metabolic activation by the phase I enzymes, such as cytochrome P450 (CYP) 1A1, CYP2A6 and CYP2E1. The transcriptional regulation of these phase I enzymes is regulated by arylhydrocarbon receptor (AH-R) which binds many well-known carcinogens. To identify a cause and effect relationship, the expression of cytochrome CYP and AH-R in the bronchial epithelium was correlated with the history of cigarette smoking in patients with non-small cell lung carcinoma (NSCLC). Although CYP3A+ cells were absent in the bronchial epithelium of all patients, there were many CYP2E1+ cells in heavy (>1000 cigarette/day x year) smokers (38.5%). In contra-distinction, there was significantly less number of CYP2E1+ cells in light (less than 1000 cigarette/day x year) smokers (15.6%) or non-smokers (10.0%). Similarly, there were more CYP1A1+ (19.2%) and CYP2A6+ cells in heavy (65.4%) smokers as compared to non-smokers. The number of AH-R+ cells was also significantly higher in cases with p53 mutation (62.5%) than those without (12.2%) mutation. Since in patients with early NSCLC, CYP positivity showed a close correlation with a poor survival (p less than 0.01), expression of CYP in bronchial epithelium has a prognostic potential.

A new mechanism for primary resistance to gefitinib in lung adenocarcinoma: the role of a novel G796A mutation in exon 20 of EGFR.

Subsets of non-small cell lung cancer (NSCLC) patients who carry activating somatic mutations of the epidermal growth factor receptor (EGFR) have demonstrated an increased probability of obtaining objective responses to the receptor tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib. However, a substantial proportion of the cases with somatic mutations, which suggest sensitivity to gefitinib, are primary resistant to it. A primary resistant case of lung adenocarcinoma that was found to carry both delE746-A750 and a G796A mutation in the EGFR is reported. In vitro, a stable clone of cells bearing the G796A mutation was approximately 50,000-fold less sensitive to gefitinib in comparison to cells carrying the delE746-A750 mutant EGFR. This study suggests that screening tumour samples for a range of EGFR mutations may improve our ability to identify the patients most likely to benefit from EFGR TKIs.

A comparison of covalent binding of ethanol metabolites to DNA according to Aldh2 genotype.

In order to clarify the effects of ALDH2 polymorphism on the carcinogenicity and organ damage caused by ethanol consumption, labeled ethanol was administered to wild-type (C57BL/6, Aldh2+/+) and Aldh2 knock-out (Aldh2-/-) mice, and DNA adduct levels of organs were compared according to Aldh2 genotype. Aldh2-/- mice, which have the same genetic background as C57BL/6 mice except in the Aldh2 gene, were used as a model of lack of ALDH2 activity in humans. The DNA adduct levels in liver, stomach, and kidney and radioactivity in liver, stomach, kidney, and serum were measured by liquid scintillation counting 6, 12, and 24h after administration. Though radioactivity levels in all organs decreased over time, there were no significant differences in radioactivity between Aldh2+/+ and Aldh2-/- mice. On the other hand, the DNA radioactivity in each organ tested differed significantly between Aldh2+/+ and Aldh2-/- mice 24h after administration. These findings show that ethanol consumption affects DNA in Aldh2-/- mice much more strongly than in Aldh2+/+ mice. According to the IARC document, ethanol consumption is carcinogenic to humans (Group 1). Moreover, several studies have shown that ALDH2-deficient humans who habitually consume ethanol have higher rates of cancer than humans with ALDH2. Our results support these findings of epidemiological studies.

Single-dose ethanol administration downregulates expression of cytochrome p450 2E1 mRNA in aldehyde dehydrogenase 2 knockout mice.

The polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is very common in East Asian origin. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people with ALDH2*2 because the mutant ALDH2 protein lacks the activity of acetaldehyde metabolism. On the other hand, it is well established that one of the cytochrome P450 enzymes, CYP2E1, is an activator of carcinogens (e.g., nitorosamines) and a generator of oxidative stress, and it is shown that CYP2E1 was induced by ethanol via gene transcriptional regulation. In the present study, to examine the consequences of ALDH2 polymorphism on transcriptional regulation of CYP2E1 in liver tissue, Aldh2+/+ and Aldh2-/- mice were orally administered 5 g/kg body weight of ethanol and the levels of CYP2E1 mRNA in liver tissue then analyzed. The level of CYP2E1 mRNA 12h after the ethanol administration tended to be higher than the 0-h group in Aldh2+/+ mice, however, it was significantly lower than the 0-h group in Aldh2-/- mice. These findings suggest that single-dose ethanol administration downregulates the expression of cytochrome p450 2E1 mRNA in the presence of inactive ALDH2.

Lack of aldehyde dehydrogenase ameliorates oxidative stress induced by single-dose ethanol administration in mouse liver.

Polymorphism of aldehyde dehydrogenase 2 (ALDH2), denoted ALDH2*2, is far more common in East Asian countries. Acetaldehyde, an intermediate metabolite of ethanol, is metabolized very slowly in people who have ALDH2*2, as the mutated ALDH2 lacks acetaldehyde metabolizing activity. On the other hand, it is well established that metabolism of ethanol causes oxidative stress in liver tissue. To examine the consequences of this polymorphism on ethanol-induced oxidative stress in liver tissue, we conducted a study using Aldh2 knockout mice. Aldh2+/+ and Aldh2-/- mice were orally administered ethanol at a dose of 5g/kg body weight. Levels of malondialdehyde, an indicator of oxidative stress, and glutathione, a key antioxidant, in liver tissue were analyzed 0-24h after administration. Levels of malondialdehyde were significantly lower in Aldh2-/- mice than in Aldh2+/+ mice at 12h after injection, while levels of glutathione were higher in Aldh2-/- mice than in Aldh2+/+ mice at 6 and 12h after injection. Our results suggest that a lack of ALDH ameliorates ethanol-induced oxidative stress in liver tissue.

Clinicopathologic significance of an immunohistochemical expression of p27 in scirrhous carcinoma of the breast.

BACKGROUND: Scirrhous carcinoma has been known to have more aggressive biological behavior than other histologic subtypes of invasive ductal carcinoma of the breast. The significance of expression of p27kip1, which is thought to be a tumor suppressor gene, in breast carcinoma remains controversial. The aim of the current study was to clarify clinicopathologic significance of scirrhous carcinoma of the breast with special reference to p27 expression. METHODS: Clinicopathologic features including immunohistochemical expression of p27 were compared between scirrhous carcinoma (n=42) and non-scirrhous invasive ductal carcinoma (papillotubular and solid-tubular carcinoma, n=63) of the breast. RESULTS: The proportion of pathologic lymph node metastasis among scirrhous carcinomas was significantly higher than that among carcinomas of other histologic types (papillotubular or solid-tubular carcinomas, p=0.029). The proportion of strong expression of p27 among scirrhous carcinomas was significantly lower than that among tumors of other histologic types (p<0.0001). CONCLUSIONS: Biological behavior of scirrhous carcinoma was found to be aggressive. The aggressiveness and poor cellular differentiation of scirrhous carcinoma of the breast might be related to low p27 expression.

Ethanol-induced oxidative DNA damage and CYP2E1 expression in liver tissue of Aldh2 knockout mice.

Excessive alcohol consumption is associated with increased risks of many diseases including cancer. We evaluated oxidative DNA damage in Aldh2 +/+ and Aldh2 -/- mice after they had been subjected to acute ethanol exposure. Olive tail moment, which was measured using a comet assay, was not increased by ethanol treatment in both Aldh2 +/+ and Aldh2 -/- mice. However, after controlling for the effect of ethanol exposure, the Aldh2 genotype was a significant determinant for Olive tail moments. Although the ethanol treatment significantly increased the hepatic 8-OHdG generation in only Aldh2 +/+ mice, the level of 8-OHdG was the highest in Aldh2 -/- ethanol treated mice. The increase in the level of 8-OHdG was associated with hepatic expression of cytochrome P450 2E1 (CYP2E1). The levels of Olive tail moment and the hepatic 8-OHdG in the Aldh2 -/- control group were significantly higher than those of the Aldh2 +/+ control group. The level of CYP2E1 in liver tissue showed a similar pattern to those of the oxidative DNA damage markers. This study shows that acute ethanol consumption increases oxidative DNA damage and that expression of CYP2E1 protein may play a pivotal role in the induction of oxidative DNA damage. The finding that oxidative DNA damage was more intense in Aldh2 -/- mice than in Aldh2 +/+ mice suggests that ALDH2-deficient individuals may be more susceptible than wild-type ALDH2 individuals to ethanol-mediated liver disease, including cancer.