Interaction between alcohol dehydrogenase II gene, alcohol consumption, and risk for breast cancer

Influence of alcohol consumption and alcohol metabolism variants on breast cancer risk among Black women: results from the AMBER consortium

BACKGROUND

Moderate to heavy alcohol consumption is associated with an increased risk of breast cancer. The etiologic role of genetic variation in genes involved in ethanol metabolism has not been established, with little information available among women of African ancestry.

METHODS

Our analysis from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium included 2889 U.S. Black women who were current drinkers at the time of breast cancer diagnosis (N cases = 715) and had available genetic data for four ethanol metabolism genomic regions (ADH, ALDH, CYP2E1, and ALDH2). We used generalized estimating equations to calculate genetic effects, gene* alcohol consumption (≥ 7drinks/week vs. < 7/week) interactions, and joint main plus interaction effects of up to 23,247 variants in ethanol metabolism genomic regions on odds of breast cancer.

RESULTS

Among current drinkers, 21% of cases and 14% of controls reported consuming ≥ 7 drinks per week. We identified statistically significant genetic effects for rs79865122-C in CYP2E1 with odds of ER- breast cancer and odds of triple negative breast cancer, as well as a significant joint effect with odds of ER- breast cancer (≥ 7drinks per week OR = 3.92, < 7 drinks per week OR = 0.24, p_joint = 3.74 × 10^-6). In addition, there was a statistically significant interaction of rs3858704-A in ALDH2 with consumption of ≥ 7 drinks/week on odds of triple negative breast cancer (≥ 7drinks per week OR = 4.41, < 7 drinks per week OR = 0.57, p_int = 8.97 × 10^-5).

CONCLUSIONS

There is a paucity of information on the impact of genetic variation in alcohol metabolism genes on odds of breast cancer among Black women. Our analysis of variants in four genomic regions harboring ethanol metabolism genes in a large consortium of U.S. Black women identified significant associations between rs79865122-C in CYP2E1 and odds of ER- and triple negative breast cancer. Replication of these findings is warranted.

Alcohol drinking, ADH1B and ADH1C genotypes and the risk of postmenopausal breast cancer by hormone receptor status: the Netherlands Cohort Study on diet and cancer

Alcohol consumption has consistently been shown to increase breast cancer (BC) risk. This association may be modified by single nucleotide polymorphisms (SNPs) in alcohol dehydrogenase (ADH) isoenzymes ADH1B and ADH1C. The Netherlands Cohort Study comprises 62 573 women, aged 55-69 years at baseline (1986). Follow-up for postmenopausal BC for 20.3 years was available. Genotyping of six tag SNPs in ADH1B and ADH1C was performed on DNA from toenails. A case-cohort approach was used for analysis (complete data available for nsubcohort = 1301; ncases = 1630). Cox regression models for postmenopausal BC were applied to determine marginal effects of alcohol intake and SNPs using a dominant genetic model, as well as multiplicative interaction of the two. Results were also obtained for subtypes by estrogen receptor (ER) and progesterone receptor (PR) status. Multiple testing was adjusted for by applying the false discovery rate (FDR). Alcohol intake (categorical) increased the risk of postmenopausal BC (Ptrend = 0.031). Trends for ER and PR subgroups followed a similar pattern. Continuous modeling of alcohol resulted in a hazard rate ratio (HR) for overall postmenopausal BC of 1.09 (95% confidence interval: 1.01-1.19) per 10 g/day of alcohol. SNPs were not associated with BC risk. No effect modification of the alcohol-BC association by SNP genotype was seen after FDR correction in overall BC and ER/PR subgroups. In conclusion, alcohol consumption was shown to increase the risk of postmenopausal BC. This association was not significantly modified by common SNPs in ADH1B and ADH1C, neither in overall BC nor in hormone receptor-defined subtypes.

Alcohol and breast cancer: reconciling epidemiological and molecular data

Breast cancer is the most diagnosed cancer in women worldwide. Epidemiological studies have suggested a possible causative role of alcohol consumption as a risk factor for breast cancer. However, such conclusions should be interpreted with considerable caution for several reasons. While epidemiological studies can help identify the roots of health problems and disease incidence in a community, they are by necessity associative and cannot determine cause and effect relationships. In addition, all these studies rely on self-reporting to determine the amount and type of alcoholic beverage consumed, which introduces recall bias. This is documented in a recent study which stated that the apparent increased risk of cancer among light-moderate drinkers may be "substantially due to underreporting of intake." Another meta-analysis about alcohol and breast cancer declared "the modest size of the association and variation in results across studies leave the causal role of alcohol in question." Furthermore, breast cancer develops over decades; thus, correlations between alcohol consumption and breast cancer cannot be determined in epidemiological studies with windows of alcohol exposure that captures current or recent alcohol intake, after clinical diagnosis. Numerous risk factors are involved in breast carcinogenesis; some are genetic and beyond the control of a woman; others are influenced by lifestyle factors. Breast cancer is a heterogeneous and polygenic disease which is further influenced by epigenetic mechanisms that affect the transciptomes, proteomes and metabolomes, and ultimately breast cancer evolution. Environmental factors add another layer of complexity by their interactions with the susceptibility genes for breast cancer and metabolic diseases. The current state-of-knowledge about alcohol and breast cancer association is ambiguous and confusing to both a woman and her physician. Confronting the huge global breast cancer issue should be addressed by sound science. It is advised that women with or without a high risk for breast cancer should avoid overconsumption of alcohol and should consult with their physician about risk factors involved in breast cancer. Since studies associating moderate alcohol consumption and breast cancer are contradictory, a woman and her physician should weigh the risks and benefits of moderate alcohol consumption.

Alcohol Intake and Breast Cancer Risk: Weighing the Overall Evidence

Moderate alcohol consumption has been linked to an approximate 30-50% increased risk in breast cancer. Case-control and cohort studies have consistently observed this modest increase. We highlight recent evidence from molecular epidemiologic studies and studies of intermediate markers like mammographic density that provide additional evidence that this association is real and not solely explained by factors/correlates of the exposure and outcome present in non-randomized studies. We also review evidence from studies of higher risk women including BRCA1 and BRCA2 mutation carriers. Given the incidence of heart disease is higher than breast cancer and modest alcohol consumption is associated with reduced risk of heart disease, we examine the latest evidence to evaluate if alcohol reduction should be targeted to women at high risk for breast cancer. We also review the most recent evidence on the effect of alcohol use on tumor recurrence and survival for those diagnosed with breast cancer.

Alcohol Intake and Breast Cancer Risk: Weighing the Overall Evidence

Moderate alcohol consumption has been linked to an approximate 30-50% increased risk in breast cancer. Case-control and cohort studies have consistently observed this modest increase. We highlight recent evidence from molecular epidemiologic studies and studies of intermediate markers like mammographic density that provide additional evidence that this association is real and not solely explained by factors/correlates of the exposure and outcome present in non-randomized studies. We also review evidence from studies of higher risk women including BRCA1 and BRCA2 mutation carriers. Given the incidence of heart disease is higher than breast cancer and modest alcohol consumption is associated with reduced risk of heart disease, we examine the latest evidence to evaluate if alcohol reduction should be targeted to women at high risk for breast cancer. We also review the most recent evidence on the effect of alcohol use on tumor recurrence and survival for those diagnosed with breast cancer.

Alcohol, genetics and risk of breast cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial

We tested the hypothesis that genes involved in the alcohol oxidation pathway modify the association between alcohol intake and breast cancer. Subjects were women aged 55-74 at baseline from the screening arm of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Incident breast cancers were identified through annual health surveys. Controls were frequency matched to cases by age and year of entry into the trial. A self-administered food frequency questionnaire queried frequency and usual serving size of beer, wine or wine coolers, and liquor. Three SNPs in genes in the alcohol metabolism pathway were genotyped: alcohol dehydrogenase 2, alcohol dehydrogenase 3, and CYP2E1. The study included 1,041 incident breast cancer cases and 1,070 controls. In comparison to non-drinkers, the intake of any alcohol significantly increased the risk of breast cancer, and this risk increased with each category of daily alcohol intake (OR 2.01, 95% CI 1.14, 3.53) for women who drank three or more standard drinks per day. Stratification by genotype revealed significant gene/environment interactions. For the ADH1B gene, there were statistically significant associations between all levels of alcohol intake and risk of breast cancer (all OR > 1.34 and all lower CI > 1.01), while for women with the GA or AA genotype, there were no significant associations between alcohol intake and risk of breast cancer. Alcohol intake, genes involved in alcohol metabolism and their interaction increase the risk of breast cancer in post-menopausal women. This information could be useful for primary care providers to personalize information about breast cancer risk reduction.

Alcohol dehydrogenase 1B genotype and fetal alcohol syndrome: a HuGE minireview

Fetal alcohol syndrome (FAS), 1 of the most common developmental disabilities in the United States, occurs at a rate of 0.5-2.0:1000 live births. Animal model, family, and twin studies suggest a genetic component to FAS susceptibility. Alcohol dehydrogenases (ADHs) catalyze the rate-limiting step in alcohol metabolism. Studies of genetic associations with FAS have focused on the alcohol dehydrogenase 1B (ADH1B) gene, comparing mothers and children with the alleles ADH1B*2 or ADH1B*3, associated with faster ethanol metabolism, with those homozygous for ADH1B*1. While most studies have found a protective effect for genotypes containing ADH1B*2 or ADH1B*3, results have been conflicting, and further investigation into the association between the ADH1B genotype and FAS is needed. Whether increased alcohol intake accounts for the elevated risk reported for the ADH1B*1/ADH1B*1 genotype should be addressed, and future studies would benefit from consistent case definitions, enhanced exposure measurements, larger sample sizes, and careful study design.

Overview of the role of alcohol dehydrogenase and aldehyde dehydrogenase and their variants in the genesis of alcohol-related pathology

Alcohol dehydrogenase (ADH) and mitochondrial aldehyde dehydrogenase (ALDH2) are responsible for metabolizing the bulk of ethanol consumed as part of the diet and their activities contribute to the rate of ethanol elimination from the blood. They are expressed at highest levels in liver, but at lower levels in many tissues. This pathway probably evolved as a detoxification mechanism for environmental alcohols. However, with the consumption of large amounts of ethanol, the oxidation of ethanol can become a major energy source and, particularly in the liver, interferes with the metabolism of other nutrients. Polymorphic variants of the genes for these enzymes encode enzymes with altered kinetic properties. The pathophysiological effects of these variants may be mediated by accumulation of acetaldehyde; high-activity ADH variants are predicted to increase the rate of acetaldehyde generation, while the low-activity ALDH2 variant is associated with an inability to metabolize this compound. The effects of acetaldehyde may be expressed either in the cells generating it, or by delivery of acetaldehyde to various tissues by the bloodstream or even saliva. Inheritance of the high-activity ADH β2, encoded by theADH2*2gene, and the inactiveALDH2*2gene product have been conclusively associated with reduced risk of alcoholism. This association is influenced by gene–environment interactions, such as religion and national origin. The variants have also been studied for association with alcoholic liver disease, cancer, fetal alcohol syndrome, CVD, gout, asthma and clearance of xenobiotics. The strongest correlations found to date have been those between theALDH2*2allele and cancers of the oro-pharynx and oesophagus. It will be important to replicate other interesting associations between these variants and other cancers and heart disease, and to determine the biochemical mechanisms underlying the associations.

Alcohol dehydrogenase genetic polymorphisms, low-to-moderate alcohol consumption, and risk of breast cancer

BACKGROUND

In vitro, human isoenzymes encoded by genes homozygous for the ADH1C*1 or ADH1B*2 alleles metabolize ethanol to acetaldehyde at a faster rate than those homozygous for the ADH1C*2 or ADH1B*1 allele. Because alcohol is a known risk factor for breast cancer, we evaluated the joint association of genetic variants in ADH and alcohol consumption in relation to breast cancer.

METHODS

A nested case-control study of 321 cases and matched controls was conducted. Five single nucleotide polymorphisms (SNPs) in the ADH1C and ADH1B genes were genotyped. Logistic regression was used to assess odds ratios (ORs) and 95% confidence limits (CIs) for each SNP. Haplotype analysis of all 5 SNPs was also undertaken.

RESULTS

Among drinkers, the median intake of total alcohol was 13 g/wk (10th-90th percentiles; 4.5-135.9) in cases and 18 g/wk (10th-90th percentiles; 4.5-104.1) in controls. Women who drank alcohol tended to be at an increased risk of developing breast cancer compared with those who did not drink (OR=1.40%, 95% CI 0.97-2.03), particularly those who were premenopausal at the time of breast cancer diagnosis (OR=2.69%, 95% CI: 1.00-7.26). Of the known functional alleles, breast cancer risk was not significantly increased among carriers of at least 1 ADH1C*1 or ADH1B*2 allele, when compared with those homozygous for the genotype at each locus. However, breast cancer risk tended to be lower among women who inherited the G allele at ADH1B IVS1+896A>G (OR=0.62, 95% CI 0.37-1.04). Overall haplotype frequencies were not significantly different between cases and controls.

CONCLUSIONS

In this study low levels of alcohol are associated with a modest increase in breast cancer risk that is not altered by known functional allelic variants of the ADH1B and 1C gene. The protective association conferred by the G allele at ADH1B IVS1+896A>G needs further evaluation.

Alcohol metabolism, alcohol intake, and breast cancer risk: a sister-set analysis using the Breast Cancer Family Registry

Moderate alcohol intake has been consistently associated with a modest (30-50%) increase in breast cancer risk, but it remains unclear if certain individuals have higher susceptibility to the harmful effects of alcohol intake. Individuals differ in their ability to metabolize alcohol through genetic differences in alcohol dehydrogenase (ADH), the enzyme that catalyzes the oxidation of approximately 80% of ethanol to acetaldehyde, a known carcinogen. Using data from the Breast Cancer Family Registry (n = 811 sister sets), we examined whether sisters with breast cancer differ with respect to alcohol consumption and alcohol metabolism (measured by polymorphisms in ADH1B and ADH1C) compared to their sisters without breast cancer. Neither alcohol drinking nor alcohol metabolizing ADH1B and ADH1C genotypes were associated with breast cancer risk. However, only 19% and 42% of sisters were discordant by ADH1B and ADH1C, respectively, and even fewer were discordant by both genotype and alcohol intake, making it difficult to detect differences if they existed.

Activity of alcohol dehydrogenase (ADH) isoenzymes and aldehyde dehydrogenase (ALDH) in the sera of patients with breast cancer

Numerous experiments have shown that alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) play a significant role in the metabolism of many biological substances. Some metabolic disorders that can lead to breast carcinogenesis may be the cause of changes in ADH and ALDH activity. In previous experiments we found a changed level of class I ADH activity in breast cancer tissues. The changed level of this enzyme in cancer cells may be reflected by the enzyme's activity in the serum. Therefore, in this study we measured the activity of ADH isoenzymes and ALDH in the sera of patients with breast cancer. Serum samples were taken for routine biochemical investigation from 45 women with breast cancer before treatment. Among all tested classes of ADH isoenzymes, only class I had higher activity in the serum of patients with breast cancer in stage IV. The total ADH and ALDH activities were not significantly higher in patients with breast cancer than in healthy controls. The changes in activity, especially in class I ADH, appear to be caused by isoenzymes being released from the organ damaged by metastatic disease.

Alcohol dehydrogenase 1B (ADH1B) genotype, alcohol consumption and breast cancer risk by age 50 years in a German case-control study

In a population-based study of 613 cases and 1082 controls, alcohol dehydrogenase 1B (ADH1B) genotype was not an independent risk factor for breast cancer, athough the possibility was raised that it modifies risk associated with high levels of alcohol consumption (OR 1.1, 95% confidence interval (CI) 0.8–1.6 for ADH1B*1/*1 genotype vs 0.2, 95% CI 0.1–1.0 for ADH1B*2 carriers).

Age-specific detriments to quality of life among breast cancer patients one year after diagnosis

The aim of our study was to identify any differences in the quality of life (QOL) of breast cancer survivors one year after diagnosis when the acute treatment effects should not longer be apparent. QOL was assessed in a population-based cohort of 387 women with breast cancer from Saarland (Germany) using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC-QLC30). Functional and symptom QOL-scores were compared with published reference data from the general population. Breast cancer survivors and women from the general population reported similar scores of global health/QOL. However, major deficits among women with breast cancer were found, for emotional, social, role and cognitive functioning. Age-specific comparisons between breast cancer patients and the reference population revealed that these deficits are predominantly found in younger age groups. The overall QOL of life of breast cancer survivors one year after diagnosis is comparable to women from the general population. However, some differences exist that seem to predominantly affect younger women who show a poorer QOL in certain domains.

The impact of alcohol use in community-dwelling older adults

The purpose of this study was to explore the use of alcohol in community-dwelling older adults and to consider differences in physical and mental health, function, cognitive status, and social supports between those who drink minimal (1 to 3 glasses weekly), moderate (4 to 7 glasses weekly), or no alcohol. A total of 3305 older adults with a mean age of 81.6 -/+ 6.0 participated in the study. Twenty-two percent (n = 709) of the participants had 1 to 3 drinks weekly, only 1% (n = 18) reported 4 to 7 drinks weekly, and none of the participants admitted to 8 or more drinks. There was no difference in drinking behavior with regard to age (F = 1.1, p >.05) or social supports (F =.39, p >.05). There was a difference in drinking behavior with regard to physical health (F = 4.9, p <.05), functional status (F = 7.7, p <.05), cognitive status (F = 11.8, p <.05), and mental health (F = 6.9, p <.05). Health care providers should use an individualized approach to alcohol use in older adults and help these individuals establish, as appropriate, safe drinking habits that will augment health and quality of life.

Nutrition and lifestyle factors on the risk of developing breast cancer

Aspects of nutrition and lifestyle may be largely responsible for the development of common cancers in Western countries, as indicated by the large differences in breast cancer rates between countries, the striking changes in these rates among migrating populations, and the rapid changes over time within countries. The better informed and increasingly health-conscious population of the present day are intensively seeking to identify and eliminate these putative carcinogenic risk factors and to exploit the preventive effects that have been attributed to certain dietary components. Nutrition and 'lifestyle' may exert its carcinogenic effects indirectly by cell stimulations (alcohol, hormone therapy in postmenopause), inhibition of DNA-repair mechanisms (lack of vitamins), effecting estrogen metabolism (phytoestrogenes), or as promotors to enhance growth of tumours (body mass index). Some 'substances' may act as a carcinogenic itself, for example, aromatic hydrocarbons in tobacco or increased polycyclic aromatic hydrocarbons in well done meat. Individual differences in the effects of nutritional factors on mammary epithelia could be caused by genetic polymorphisms. In this critical review, we focus on current data regarding the effect of nutrition and lifestyle, on the risk of developing breast cancer. A health lifestyle, consisting of 'healthy diet', physical activity, renunciation of stimulants, is recommended from childhood throughout life.

Relation among alcohol dehydrogenase 2 polymorphism, alcohol consumption, and levels of gamma-glutamyltransferase

In human beings, alcohol is metabolized primarily by alcohol dehydrogenase 2 (ADH2) and acetaldehyde dehydrogenase 2 (ALDH2). Whereas polymorphisms of the ALDH2 are common in Asian persons, polymorphisms of the ADH2 seem to be more important in Caucasian individuals. The aim of this study was to assess the relation among ADH2 polymorphism, alcohol consumption, and levels of gamma-glutamyltransferase (GGT). The question was examined among 1,663 subjects (736 men and 927 women) participating in a national representative health and nutrition survey (VERA substudy of the German National Nutrition Survey). Alcohol consumption was assessed through responses to a semiquantitative food frequency questionnaire (FFQ), and the ADH2 restriction fragment length polymorphism (RFLP) Mae III and GGT levels were analyzed from frozen serum samples. The relations between the polymorphism and alcohol consumption and between alcohol consumption and GGT levels according to the polymorphism were assessed with the use of descriptive statistics and contingency table analysis. Of the subjects studied, 2.8% were homozygous or heterozygous for the ADH2*2 allele, and high levels of alcohol consumption (>20 g/day) were less common among these subjects (8.5%) than among subjects with the ADH2*1 allele (19.9%). Median levels of GGT increased with increasing levels of alcohol consumption. This increase tended to be stronger among subjects with the ADH2*2 allele than among other subjects, although differences were not statistically significant (P value for interaction=.1) given the small number of subjects with the polymorphism. These results are consistent with the hypothesis that subjects with the ADH2*2 allele, on the one hand, might tend to drink less alcohol but, on the other hand, might be at increased risk of alcohol-related effects on the liver with consumption of larger amounts of alcohol. However, this hypothesis needs to be evaluated among larger population samples.