The alcohol flush reaction represents one of the most visible and clinically consequential manifestations of human pharmacogenetic diversity, linking inherited metabolic variations directly to acute physiological discomfort and chronic oncological risk. Far from being a benign cosmetic phenomenon, this immediate dermatological and cardiovascular response serves as a biological indicator of cellular toxicity caused by defective ethanol processing. Exploring the underlying genetics, metabolic pathways, and systemic manifestations of this reaction provides crucial insights into personalized medicine, preventive oncology, and evolutionary biochemistry.
Alcohol Flush Reaction (AFR)
1. Concise Definition
Alcohol flush reaction (AFR) is an inherited metabolic condition characterized by rapid cutaneous erythema, facial vasodilation, tachycardia, nausea, headache, and physical discomfort following the ingestion of alcoholic beverages. The condition is driven primarily by an enzymatic defect in the ethanol metabolism pathway, which causes a rapid and toxic accumulation of blood acetaldehyde shortly after alcohol consumption.
Predominantly associated with single-nucleotide polymorphisms in genes encoding alcohol-metabolizing enzymes—most notably the ALDH2*2 variant of mitochondrial aldehyde dehydrogenase—the reaction reflects an inability to clear toxic intermediates into inert acetate. As a consequence, afflicted individuals experience systemic vasodilation triggered by endogenous histamine release, elevated catecholamines, and direct vascular endothelial stimulation. Beyond its immediate vasomotor presentations, the physiological cascade underpinning the alcohol flush reaction serves as an epidemiological biomarker for heightened susceptibility to alcohol-induced malignancies, including esophageal and upper aerodigestive tract cancers.
2. Etymology & Linguistic Origin
The term “alcohol flush reaction” comprises three distinct linguistic components derived through Latin, Middle English, and German etymological roots. The primary noun “alcohol” traces back historically to the Arabic al-kuḥl (denoting a fine powder of purified stibnite or antimony used as cosmetic eye shadow), which entered Medieval Latin via alchemical scholarship as a descriptor for any vaporous, sublimated, or highly distilled essence, eventually narrowing in the eighteenth and nineteenth centuries to refer specifically to ethanol (C2H5OH).
The word “flush” originates in early modern English, likely emerging from a blend of the Middle English fluschen (signifying a sudden surge, flight of birds, or gush of water) and the Latin fluxus (a flowing or loose state). Its medical application to express sudden, transient capillary engorgement and cutaneous redness arose during the late seventeenth century. “Reaction” entered scientific parlance from the late Latin re- (meaning “again” or “back”) and agere (meaning “to act” or “to drive”), conceptualizing a physiological counter-response to an external stimulus. In early biochemical and ethnographic literature, the phenomenon was historically referred to as “oriental flushing syndrome” or “Asian flush,” nomenclature that contemporary scientific and medical lexicons have largely replaced with “alcohol flush reaction” or “acetaldehyde-induced flushing” to eliminate regional stigmatization and emphasize precise pathophysiological mechanisms.
3. Pronunciation & Grammatical Form
The term is pronounced phonetically as /ˈæl.kə.hɒl flʌʃ riˈæk.ʃən/ in British English and /ˈæl.kə.hɑːl flʌʃ riˈæk.ʃən/ in American English. Grammatically, it functions as a compound noun phrase, wherein “alcohol” and “flush” serve as attributive nouns modifying the base noun “reaction.”
Common clinical and technical variants include “alcohol-induced flushing response,” “acetaldehyde flushing syndrome,” and the abbreviation “AFR.” In adjectival constructions, medical writers frequently reference “alcohol-flushing phenotypes” or “flushing-positive individuals,” categorizing subjects based on the presence or absence of the diagnostic physiological response upon alcohol challenge.
4. Detailed Conceptual Explanation
To fully grasp the alcohol flush reaction, one must examine the two-step hepatic oxidation cascade responsible for the human body’s clearance of ingested ethanol. In the primary phase of this pathway, cytosolic alcohol dehydrogenase (primarily the ADH1B and ADH1C isoenzymes) oxidizes ethanol into acetaldehyde, an unstable, highly reactive, and cytotoxic intermediate. Under normal physiological circumstances, mitochondrial aldehyde dehydrogenase (specifically the ALDH2 enzyme) rapidly sequesters and oxidizes acetaldehyde into nontoxic acetate, which is subsequently converted into acetyl-CoA and safely eliminated via peripheral tissue metabolism and the citric acid cycle.
In individuals displaying the alcohol flush reaction, this enzymatic synchronization is fundamentally broken. This disruption typically arises from a structural mutation in the ALDH2 gene located on chromosome 12 (12q24.12), where a single guanine-to-adenine transition causes a substitution of glutamate for lysine at position 487 (Glu487Lys, or Glu504Lys depending on numbering conventions). The mutated enzyme, designated ALDH2*2, exhibits a structural alteration near its catalytic active site and subunit interfaces. Because active ALDH2 is a homotetramer, the incorporation of even a single mutated ALDH2*2 subunit into the complex drastically destabilizes the enzyme and abolishes its catalytic efficacy. As a result, heterozygous individuals (ALDH2*1/*2) retain only 10% to 40% of standard enzymatic activity, whereas homozygous individuals (ALDH2*2/*2) possess virtually undetectable clearance capacity.
When an individual with impaired enzymatic function consumes ethanol, hepatic conversion to acetaldehyde outpaces clearance by several orders of magnitude. Within minutes, circulating levels of acetaldehyde surge to concentrations between six and twenty times higher than those observed in individuals with wild-type alleles. This reactive aldehyde operates as a potent physiological stressor. It interacts directly with the vascular endothelium, drives systemic mast cell degranulation, promotes the release of endogenous histamine and neuropeptides, and stimulates the sympathetic nervous system. The immediate clinical manifestation of this cascade is pronounced peripheral vasodilation, accompanied by a rise in core skin temperature, cutaneous erythema concentrated across the face, neck, and torso, compensatory sinus tachycardia, pulsatile cephalalgia, and severe visceral distress.
5. Historical Development
Initial medical interest in population-specific alcohol sensitivities surfaced during the early twentieth century, yet systematic scientific documentation did not mature until the early 1970s. In 1972, pediatrician and geneticist Peter H. Wolff published a landmark comparative study in Science demonstrating that neonates and adults of East Asian ancestry displayed profound facial vasodilation, pupillary dilation, and cardiovascular arousal in response to small doses of ethanol—symptoms largely absent in individuals of European ancestry. Wolff postulated that an innate, genetically fixed autonomic or metabolic variation governed these divergent physical responses.
During the late 1970s and early 1980s, biochemical geneticists H. Werner Goedde, Dharam P. Agarwal, and Shoji Harada at the University of Hamburg isolated human liver aldehyde dehydrogenase isoenzymes and demonstrated that the biological driver of the flushing phenomenon was not heightened adrenergic tone, but rather the absence of the mitochondrial low-Km aldehyde dehydrogenase isoenzyme (ALDH I, later classified as ALDH2). Their studies clarified that the phenotypic response directly correlated with defective enzymatic conversion of acetaldehyde.
The genetic architecture of the phenomenon became fully resolved in the late 1980s through the molecular cloning work of Akira Yoshida and colleagues, who identified the specific point mutation responsible for the catalytic deficiency. In subsequent decades, researchers led by Philip J. Brooks at the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and Akira Yokoyama in Japan uncovered the broader epidemiological implications of this trait. They established that despite the aversive physical sensations of the flush, individuals who circumvent these symptoms and consume moderate-to-heavy amounts of alcohol face an exponentially elevated risk of upper aerodigestive tract cancers, fundamentally transforming the understanding of AFR from an uncomfortable vasomotor condition into a recognized public health priority.
6. Theoretical Foundations
The study of alcohol flush reaction intersects three major biological frameworks: pharmacogenomics, evolutionary medicine, and biochemical carcinogenesis. Within pharmacogenomics, AFR serves as a classic textbook paradigm of gene-environment interactions. In this context, an individual’s inherited genetic constitution directly dictates their metabolic tolerance, toxicity thresholds, and behavioral patterns when exposed to a specific chemical substrate.
From an evolutionary perspective, researchers debate why a deleterious mutation like ALDH2*2 achieved such substantial allele frequencies (between 30% and 50%) throughout populations originating in southeastern China and surrounding regions. One leading evolutionary hypothesis suggests that the mutation conferred balanced protective advantages against historical infectious diseases. Some theorists propose that transient elevations in toxic acetaldehyde or allied metabolic shifts hindered the intracellular propagation of specific pathogens, such as Mycobacterium tuberculosis or parasitic protozoa, granting a survival advantage in high-density agrarian environments. An alternative evolutionary hypothesis views ALDH2*2 as a protective mechanism against severe alcohol dependence, noting that the acute physical discomfort of AFR serves as an evolutionary deterrent against chemical misuse.
Within the framework of molecular carcinogenesis, the theoretical foundation of AFR rests upon the electrophilic reactivity of acetaldehyde. Because ALDH2 is ineffective, the aldehyde persists in mucosal tissues and systemic circulation, where it reacts directly with cellular DNA to produce stable DNA adducts, such as N2-ethylidene-2′-deoxyguanosine. These structural adducts impede DNA replication, provoke double-strand chromosome breaks, and induce point mutations in critical tumor-suppressor pathways, including TP53. Consequently, the condition provides a functional model linking genetic metabolic deficiency directly to environmental chemical oncogenesis.
7. Key Components, Types & Dimensions
The clinical and physiological presentation of the alcohol flush reaction can be categorized across genotypic classifications, enzymatic dynamics, and systemic organ responses:
- Heterozygous Inactivation (ALDH2*1/*2): Individuals carrying one normal and one mutated allele display intermediate enzyme activity (approximately 10% to 40%). They experience moderate-to-severe flushing reactions upon consuming alcohol, but their partial metabolic capacity allows some individuals to develop behavioral tolerance to the discomfort.
- Homozygous Inactivation (ALDH2*2/*2): Individuals carrying two mutated alleles exhibit a complete loss of catalytic ALDH2 activity. Ingestion of even minimal amounts of alcohol (less than 5 to 10 grams) provokes severe nausea, extreme tachycardia, dizziness, and intense systemic flushing, functioning as an absolute biological barrier against continuous alcohol consumption.
- Super-Active Alcohol Dehydrogenase Interactions (ADH1B Variants): The flushing phenotype is frequently amplified by co-occurring mutations in the alcohol dehydrogenase pathway, such as the ADH1B*2 (Arg47His) allele. This variant metabolizes ethanol into acetaldehyde up to 40 times faster than the wild-type enzyme, flooding the bloodstream with acetaldehyde before even normal enzymes could metabolize it.
- Cutaneous Vasomotor Manifestation: The most recognizable dimension of AFR, involving intense vasodilation of the superficial microvascular beds across the zygomatic, frontal, and cervical regions, often spreading across the upper chest and shoulders.
- Autonomic and Cardiovascular Manifestations: Driven by sympathetic activation and systemic vasodilation, this component includes reflexive sinus tachycardia, reductions in diastolic blood pressure, palpitations, and pulsatile temporal headaches.
- Gastrointestinal and Neurovisceral Symptoms: Systemic toxicity manifests as acute nausea, emesis, abdominal cramping, dizziness, general malaise, and subjective feelings of physical exhaustion during and after alcohol intake.
8. Examples & Illustrative Cases
The real-world manifestation of the alcohol flush reaction varies substantially depending on genotypic status, social settings, and personal awareness of the associated health risks. The following illustrative scenarios highlight the clinical spectrum of the condition:
Case 1: The Heterozygous Social Drinker
A 24-year-old male of East Asian descent attends a celebratory social event and consumes one standard serving of beer (approximately 14 grams of ethanol). Within twelve minutes, his cheeks and forehead develop an intense, clearly demarcated erythema accompanied by an elevation in local facial skin temperature. He notes a resting heart rate elevation from 68 to 110 beats per minute, accompanied by mild throbbing sensations at the temples and a scratchy sensation in the throat. He recognizes this response as identical to reactions experienced by his maternal relatives. Despite this discomfort, he continues to consume alcohol throughout the evening, noting that although the intense redness persists for several hours, the accompanying lightheadedness eventually blunts his subjective awareness of the physiological strain.
Case 2: The Severe Homozygous Reaction
A 31-year-old female drinks a single sip of dry white wine. Within three minutes, she experiences an intense, burning erythema spreading across her face, neck, and arms. She quickly develops profound orthostatic dizziness, nausea, and severe palpitations, with her heart rate rising to 135 beats per minute. Her blood pressure drops from a baseline of 115/75 mmHg to 88/55 mmHg due to widespread peripheral pooling. Her physical distress is severe enough that she must lie flat on her back, experiencing persistent nausea and a throbbing migraine for the next four hours. Genetic screening subsequently reveals an ALDH2*2/*2 homozygous genotype, indicating near-zero hepatic conversion of acetaldehyde and an absolute metabolic intolerance to ethanol.
Case 3: Masked Flushing and Late Oncological Presentation
A 52-year-old corporate executive with a lifelong history of facial flushing upon alcohol intake routinely consumed one to two packets of over-the-counter H2-receptor antagonists (such as famotidine) prior to social dinners. By suppressing histamine-mediated cutaneous vasodilation, this pharmacologic intervention allowed him to circumvent facial redness and consume three to four drinks nightly without cosmetic embarrassment. After twenty years of sustained heavy alcohol consumption, he presents to a gastroenterologist with progressive dysphagia and unprovoked weight loss. Diagnostic endoscopy reveals an advanced squamous cell carcinoma of the middle third of the esophagus. Genetic analysis confirms the ALDH2*1/*2 genotype, demonstrating how suppressing the acute flushing warning signal enabled chronic, high-volume exposure to mucosal acetaldehyde.
9. Measurement & Assessment
Clinicians and researchers evaluate and diagnose the alcohol flush reaction using qualitative behavioral surveys, simple physiological challenge tests, and definitive molecular genotyping methods.
The simplest, non-invasive method for initial clinical screening is the Ethanol Patch Test (EPT). In this assessment, a medical practitioner places a lint pad saturated with 70% ethanol onto the subject’s inner forearm for ten to twenty minutes. After removing the patch, the clinician inspects the skin at 10- and 25-minute intervals. The development of pronounced local erythema under the patch site indicates an impaired ability to clear localized acetaldehyde, showing an approximate 85% to 90% diagnostic concordance with heterozygous or homozygous ALDH2*2 status.
In epidemiological and clinical research, standardized self-report questionnaires designed by Akira Yokoyama and colleagues are widely used. The questionnaire relies on two key diagnostic questions: (1) “Do you currently have a tendency to flush in the face immediately after drinking a glass of beer?” and (2) “Did you have that tendency during the first 1 to 2 years after you started drinking?” An affirmative response to either question exhibits over 90% sensitivity and specificity for identifying individuals carrying an ALDH2*2 loss-of-function allele, making it an invaluable tool for clinical intake and large-scale demographic surveys.
The definitive gold standard for assessment is direct genomic profiling. Using quantitative polymerase chain reaction (qPCR), restriction fragment length polymorphism (RFLP) analysis, or next-generation DNA sequencing of the ALDH2 locus, clinicians can identify the Glu487Lys point mutation directly. This molecular testing definitively distinguishes between wild-type non-flushers (ALDH2*1/*1), symptomatic heterozygotes (ALDH2*1/*2), and severely intolerant homozygotes (ALDH2*2/*2).
10. Applications & Practical Significance
The practical and clinical significance of recognizing the alcohol flush reaction lies primarily in oncological prevention, cardiovascular risk management, and the avoidance of dangerous pharmacological workarounds.
The most critical application of AFR identification involves assessing cancer risk, particularly for esophageal cancer. The World Health Organization’s International Agency for Research on Cancer (IARC) classifies acetaldehyde associated with alcohol consumption as a Group 1 human carcinogen. Individuals with the ALDH2*1/*2 genotype who consume moderate-to-heavy amounts of alcohol face up to a tenfold to fiftyfold increase in the relative risk of developing esophageal squamous cell carcinoma compared to individuals with wild-type alleles who consume equivalent volumes of alcohol. Identifying an individual as an alcohol flusher provides a clear, biological rationale for medical providers to advise either strict abstinence or low-risk drinking behaviors.
Furthermore, recognizing AFR is essential for addressing the hazardous practice of using over-the-counter medications to “cure” or mask the flush. Many social drinkers take H1- and H2-antihistamines (such as cetirizine, diphenhydramine, and famotidine) or vascular constriction agents shortly before consuming alcohol. While these drugs can block histamine-mediated facial flushing, they have no impact on the underlying enzyme deficiency. By blunting the body’s natural protective warning signals—such as redness, nausea, and elevated heart rate—these medications often lead people to drink significantly larger quantities of alcohol. This dramatically increases blood acetaldehyde concentrations, creating an environment of profound, unmitigated cellular and genetic damage across the digestive tract.
11. Research & Empirical Evidence
Epidemiological and biochemical investigations have established clear connections between the alcohol flush reaction, systemic disease risks, and cellular mutagenesis. Landmark studies by Akira Yokoyama and colleagues across multiple Japanese clinical cohorts confirmed that the elevated risk of upper aerodigestive tract cancers in flushing individuals is not solely a product of alcohol volume, but is driven directly by the metabolic accumulation of acetaldehyde. When ALDH2-deficient subjects drink heavily, their salivary and mucosal acetaldehyde levels remain persistently elevated, which correlates with higher rates of multiple primary neoplasms across the oral cavity, pharynx, larynx, and esophagus.
Large-scale meta-analyses, including comprehensive reviews by Philip J. Brooks and international research consortia, have reaffirmed these findings across varied geographical populations. In individuals with the ALDH2*2 allele who consume more than 200 grams of alcohol per week, researchers observe striking hazard ratios for esophageal squamous cell carcinoma that far exceed the risks seen in wild-type drinkers. Genomic investigations have expanded this concern by showing that sustained elevated acetaldehyde levels promote the formation of complex DNA crosslinks, directly accelerating the mutational burden across gastrointestinal tissues.
Contemporary research has also identified significant non-oncological consequences associated with the ALDH2*2 variant. Clinical studies led by Che-Hong Chen and colleagues at Stanford University demonstrated that the enzymatic deficiency impairs the metabolism of reactive lipid aldehydes, such as 4-hydroxynonenal (4-HNE), which accumulate during episodes of cardiac ischemia. Consequently, individuals displaying AFR experience larger myocardial infarct sizes, poorer post-infarction outcomes, and reduced clearance of sublingual nitroglycerin, which depends on active mitochondrial ALDH2 for biotransformation into its active vasodilator form, nitric oxide.
12. Cultural & Cross-Cultural Considerations
The prevalence of the alcohol flush reaction varies substantially along ancestral and geographical lines, carrying distinct social, cultural, and psychological implications. The condition is disproportionately concentrated among populations of East Asian heritage, with allele frequencies reaching 30% to 50% among Han Chinese, Japanese, and Korean populations, while remaining rare (typically below 1% to 2%) among individuals of European, African, and Middle Eastern ancestry.
These demographic patterns create unique cultural and social dynamics. In societies where structured business and social drinking practices—such as Japanese nomikai or Korean hoesik—play an important role in professional networking and social bonding, individuals who flush frequently face conflicting pressures. Despite experiencing acute physiological discomfort, non-abstinent flushers may feel strong social pressure to participate in drinking rituals, prompting some to adopt coping strategies like consuming antihistamines or deliberately tolerating physical distress.
The cultural visibility of the condition has also influenced social perceptions. While historically stigmatized through informal or disparaging labels like “Asian glow,” public health initiatives across East Asia and in multicultural nations increasingly present the condition as a valuable genetic indicator for cancer risk. By reframing the flush reaction from an inconvenient cosmetic symptom into an important preventive health marker, public health campaigns are helping to dismantle harmful social drinking pressures across diverse cultural contexts.
13. Criticisms, Debates & Limitations
Despite significant scientific consensus regarding the core biochemistry of the alcohol flush reaction, several controversies, clinical debates, and diagnostic limitations persist within the medical literature:
One area of debate centers on the exact evolutionary pressures that led to the high prevalence of the ALDH2*2 allele. While many researchers argue that the mutation offered protective selection against ancestral infectious pathogens, others contend that the mutation may simply be a historical founder effect that spread through rapid demographic expansion in ancient agricultural centers without providing any direct evolutionary advantage.
A critical diagnostic limitation is that cutaneous flushing following alcohol intake is not exclusively caused by the ALDH2*2 mutation. Facial flushing can arise from other mechanisms, including neurogenic flushing, mast cell activation disorders, rosacea, carcinoid syndrome, or medications that block ethanol metabolism (such as disulfiram, metronidazole, or chlorpropamide). Assuming every instance of alcohol-induced flushing is caused by ALDH2 deficiency can lead to misdiagnosis or overlook alternative underlying conditions in clinical practice.
Additionally, researchers debate the effectiveness of public health interventions centered on AFR. While health agencies emphasize that flushing serves as a clear warning sign to avoid heavy drinking, observational data show that many young individuals simply ignore these warnings or turn to antihistamines to suppress their visible symptoms. This persistent gap highlights the ongoing challenge of translating genetic and clinical knowledge into lasting behavioral change.
14. Related Terms & Distinctions
The alcohol flush reaction intersects with several related medical concepts, pharmacological phenomena, and clinical conditions that require clear differentiation:
- Alcohol Intolerance: A broad term referring to any adverse physical reaction following alcohol ingestion. While AFR is a specific genetic metabolic condition, general alcohol intolerance can stem from non-genetic sensitivities, digestive disorders, or allergic reactions to ingredients in alcoholic beverages, such as sulfites or grains.
- Disulfiram-Ethanol Reaction: A medically induced condition where an individual experiences severe flushing, nausea, and tachycardia because a medication (disulfiram) chemically inhibits the ALDH2 enzyme. While the symptoms mirror AFR, this reaction is caused by pharmacological intervention rather than an inherited genetic variation.
- Rosacea: A chronic dermatological condition characterized by facial erythema, telangiectasias, and inflammatory papules. While alcohol consumption can trigger a rosacea flare, this reaction is driven by local microvascular hypersensitivity rather than a failure to metabolize acetaldehyde.
- Carcinoid Syndrome: A rare neuroendocrine disorder where tumors release high levels of serotonin, bradykinin, and histamine, causing episodes of intense flushing and abdominal cramping. These symptoms can be triggered by alcohol, but the underlying cause is neuroendocrine hypersecretion rather than an enzyme deficiency.
- Histamine Fish Poisoning (Scombroid): An acute toxicity caused by consuming improperly stored fish containing elevated histamine levels. It presents with facial erythema, headache, and palpitations similar to AFR, but it occurs independently of alcohol metabolism pathways.
15. Summary / Key Takeaways
The alcohol flush reaction is an inherited pharmacogenetic condition driven by a reduced capacity to metabolize acetaldehyde, a toxic and carcinogenic intermediate formed during alcohol clearance. Primarily caused by the ALDH2*2 allele, the condition affects hundreds of millions of people worldwide, particularly those of East Asian descent. The resulting accumulation of acetaldehyde triggers immediate physical symptoms, including facial vasodilation, elevated heart rate, headaches, nausea, and general physical distress.
Clinically, the alcohol flush reaction serves as an important biomarker for heightened oncological vulnerability. Flushing individuals who routinely consume moderate-to-heavy amounts of alcohol face an exponentially increased risk of developing esophageal squamous cell carcinoma and other cancers of the upper aerodigestive tract. Suppressing these symptoms with antihistamines poses substantial health risks by removing the body’s natural warning signals without clearing underlying cellular toxins. Recognizing the flush reaction as a meaningful genetic health indicator is essential for guiding clinical discussions, reducing hazardous alcohol consumption, and advancing personalized approaches to cancer prevention.
Ultimately, the alcohol flush reaction highlights the deep interconnectedness between evolutionary genetics, daily health behaviors, and personal disease risks. Understanding this physiological response transforms a visible cosmetic reaction into a powerful tool for preventive medicine, helping individuals make informed choices to protect their long-term health.
References
- Brooks, P. J., Enoch, M. A., Goldman, D., Li, T. K., & Yokoyama, A. (2009). The alcohol flushing response: An unrecognized risk factor for esophageal cancer from alcohol consumption. PLoS Medicine, 6(3), e1000050. https://doi.org/10.1371/journal.pmed.1000050
- Chen, C. H., Ferreira, J. C., Gross, E. R., & Mochly-Rosen, D. (2014). Targeting aldehyde dehydrogenase 2: New therapeutic opportunities. Physiological Reviews, 94(1), 1–34. https://doi.org/10.1152/physrev.00017.2013
- Goedde, H. W., Harada, S., & Agarwal, D. P. (1979). Racial differences in alcohol sensitivity: A new hypothesis. Human Genetics, 51(3), 331–334. https://doi.org/10.1007/BF00283404
- Wolff, P. H. (1972). Ethnic differences in alcohol sensitivity. Science, 175(4020), 449–450. https://doi.org/10.1126/science.175.4020.449
- Yokoyama, A., Muramatsu, T., Ohmori, T., Kumagai, Y., Higuchi, S., & Ishii, H. (1998). Alcohol and aldehyde dehydrogenase gene polymorphisms and susceptibility to esophageal cancer in Japanese alcoholics. Japanese Journal of Clinical Oncology, 28(2), 79–85. https://doi.org/10.1093/jjco/28.2.79