What you carry at this position in your DNA and what research says about it.
Liver Health and Cancer Risk: 5/10 evidence, 24 publications.
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Sample genotype (not yours): G/G
Typical Cancer Risk but Higher Drug Toxicity
A normal rate of enzyme production maintains standard baseline risks for most cancers and alcohol-related liver issues. However, undergoing treatment with first-line anti-tuberculosis medications carries an elevated risk of drug-induced liver damage.
What this genotype means: Elevated risk of liver damage during tuberculosis treatment; Typical baseline risk for lung and urinary cancers; Standard tolerance to alcohol-induced liver complications.
Sample genotype (not yours): C/C
Lower Cancer Risk but Higher Alcohol Sensitivity
Carrying two copies of the variant C allele provides the strongest protective effect against lung and urinary cancers. However, it also carries the highest risk of liver cirrhosis and hypertension if alcohol is consumed regularly.
What this genotype means: Strongest genetic protection against lung and urinary tract cancers; Highly elevated risk of liver cirrhosis and hypertension with heavy alcohol use; Lowest risk of liver toxicity from first-line tuberculosis medications.
Sample genotype (not yours): G/C
Carrying one copy of the variant C allele is associated with a reduced risk of several cancers, including lung and urinary tract cancers. However, this same genetic change increases susceptibility to alcohol-induced liver damage and hypertension.
What this genotype means: Reduced risk of lung, esophageal, and urinary cancers; Increased risk of liver cirrhosis and high blood pressure from heavy drinking; Lower risk of liver toxicity during tuberculosis therapy.
Gene function and biological role
Gene Function: The CYP2E1 gene encodes cytochrome P450 2E1, a key enzyme primarily active in the liver that metabolizes various foreign compounds, including alcohol, drugs, and environmental toxins [1]. It plays a critical role in the metabolic activation of procarcinogens, converting them into highly reactive intermediates that can damage DNA [2]. Additionally, this enzyme is responsible for processing several therapeutic medications, such as first-line anti-tuberculosis drugs [3]. Variations in this gene can significantly alter enzyme expression and activity, thereby influencing individual susceptibility to drug toxicities, liver diseases, and certain cancers [4].
Variant Impact: The rs3813867 variant, also known as CYP2E1_-1295G>C, is a single nucleotide polymorphism located in the promoter region of the CYP2E1 gene [5]. This genetic change alters the binding site for transcription factors, which directly impacts how much of the enzyme is produced [2]. The minor C allele, often referred to as the c2 allele, is associated with altered transcriptional activity and enzyme levels under certain conditions [1]. Consequently, this variant is widely studied for its role in modulating the metabolism of alcohol, environmental carcinogens, and anti-tuberculosis medications [3].
Key Insight: The same genetic variant that protects against several types of cancer also increases the risk of liver damage and high blood pressure when alcohol is consumed.
Location: CYP2E1. Chromosome 10 · 10q26.3 · 133.5 Mb
Estimated prevalence by population
Global 90.9%; European 94.8%; African 88.9%; East Asian 63.4%; South Asian 97.4%; Americas 82.5%; Ashkenazi 89.9%; Finnish 95.7%; Middle Eastern 98.6%; Amish 94.4%.
Estimated GG genotype frequency.
Global 8.8%; European 5.2%; African 10.8%; East Asian 32.4%; South Asian 2.5%; Americas 16.7%; Ashkenazi 9.8%; Finnish 4.3%; Middle Eastern 1.4%; Amish 5.5%.
Estimated GC genotype frequency.
Global 0.4%; European 0.1%; African 0.3%; East Asian 4.1%; South Asian < 0.1%; Americas 0.8%; Ashkenazi 0.3%; Finnish < 0.1%; Middle Eastern < 0.1%; Amish 0.1%.
Estimated CC genotype frequency.
Showing effects for G/G genotype
Pharmacogenomics
Antimicrobial & Antiviral Response
Tuberculosis Drug Safety. Evidence: 5/10. Source: PMID 20392357. Increased Risk.
Cancer & Oncology
Lung Cancer
Lung Cancer. Evidence: 3/10. Source: PMID 25945422. Typical Risk.
Organ Systems
Liver Function & Disease
Alcoholic Liver Disease. Evidence: 3/10. Source: PMID 22126492. Typical Risk.
Cardiovascular & Metabolic
Hypertension
Hypertension. Evidence: 3/10. Source: PMID 24288753. Typical Risk.
Showing effects for C/C genotype
Tuberculosis Drug Safety. Evidence: 5/10. Source: PMID 20392357. Reduced Risk.
Lung Cancer. Evidence: 3/10. Source: PMID 25945422. Reduced Risk.
Alcoholic Liver Disease. Evidence: 3/10. Source: PMID 22126492. Increased Risk.
Hypertension. Evidence: 3/10. Source: PMID 24288753. Increased Risk.
Showing effects for G/C genotype
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Carrying two copies of the common G allele results in normal baseline expression of the CYP2E1 enzyme [1]. This standard activity level means there is no genetically lowered risk for cancers of the lung, esophagus, or urinary tract [2]. On the positive side, standard enzyme levels do not elevate the risk of alcohol-induced liver cirrhosis or hypertension when consuming alcohol [3]. However, during treatment for tuberculosis, this genotype is associated with a significantly higher risk of experiencing severe drug-induced liver injury [4]. This occurs because the standard enzyme variant is less inhibited by isoniazid, leading to a greater accumulation of toxic drug metabolites in liver cells [4]. Monitoring liver function is particularly important for individuals with this genotype if they require anti-tuberculosis therapy [4].
Elevated risk of liver damage during tuberculosis treatment; Typical baseline risk for lung and urinary cancers; Standard tolerance to alcohol-induced liver complications.
Sample genotype: CC (Homozygous)
Having two copies of the variant C allele, or the homozygous c2/c2 genotype, maximizes the transcriptional changes in the CYP2E1 gene [1]. This genotype is associated with the lowest risk of developing lung, esophageal, and urinary tract cancers, especially in individuals of East Asian descent [2]. However, the elevated enzyme activity significantly increases the production of free radicals and toxic metabolites during alcohol metabolism [3]. Consequently, regular or heavy alcohol consumption carries a highly elevated risk of liver cirrhosis and essential hypertension [4]. During first-line tuberculosis therapy, this genotype is highly protective against drug-induced liver injury, as the variant enzyme is more easily regulated to prevent toxic drug buildup [5]. Maintaining a low-alcohol lifestyle is highly recommended to avoid the liver-damaging effects of this genotype while enjoying its natural cancer-protective benefits [3].
Strongest genetic protection against lung and urinary tract cancers; Highly elevated risk of liver cirrhosis and hypertension with heavy alcohol use; Lowest risk of liver toxicity from first-line tuberculosis medications.
Sample genotype: GC (Heterozygous)
Possessing one copy of the variant C allele, also known as the c2 allele, alters the promoter activity of the CYP2E1 gene [1]. This alteration is linked to a protective effect against several malignancies, showing a significantly reduced risk of lung, esophageal, and urinary tract cancers, particularly in Asian populations [2]. Conversely, the increased enzyme activity associated with this variant can accelerate the conversion of alcohol into toxic byproducts [3]. As a result, individuals with this genotype who drink heavily face an elevated risk of developing alcohol-induced liver cirrhosis and essential hypertension [4]. On the other hand, this genotype provides a protective buffer during tuberculosis treatment, showing a lower risk of severe drug-induced liver injury compared to the common genotype [5]. The balance of benefits and risks makes this a highly variable genetic profile depending on lifestyle factors [3].
Reduced risk of lung, esophageal, and urinary cancers; Increased risk of liver cirrhosis and high blood pressure from heavy drinking; Lower risk of liver toxicity during tuberculosis therapy.
Variants with shared genetic architecture
rs6413432 · CYP2E1 Gene · Chr 10 · Drug Metabolism and Toxicity
rs2031920 · CYP2E1 Gene · Chr 10 · Tuberculosis Drug Liver Risk
rs2070673 · CYP2E1 Gene · Chr 10 · Liver and Chemical Safety
Content updated August 2026.
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