Relationship of ALDH2 rs671 and CYP2E1 rs2031920 with hepatocellular carcinoma susceptibility in East Asians: a meta-analysis

Diagnostic Impacts of Aldehyde Dehydrogenase 2 Genetic Variants on Hepatocellular Carcinoma Susceptibility

Background/Aim

The role of alcohol consumption and aldehyde dehydrogenase 2 (ALDH2) genotype in hepatocellular carcinoma (HCC) development remains uncertain.

Materials and Methods

We conducted genotyping of the ALDH2 rs671 single nucleotide polymorphism in 298 patients with HCC and 889 non-cancerous healthy controls. We assessed associations stratified by sex and alcohol consumption status.

Results

Distribution of ALDH2 rs671 variant genotypes differed significantly between HCC patients and controls (ptrend=0.0311). Logistic regression analyses indicated that compared to the wild-type GG genotype, the heterozygous variant AG genotype and homozygous variant AA genotype conferred 1.22- and 1.77-fold increases in HCC risk (p=0.1794 and 0.0150, respectively). Allelic frequency analysis showed that the A allele was associated with a 1.29-fold increased HCC risk (p=0.0123). Additionally, AA genotype carriers had significantly higher HCC risk than GG genotype carriers among males (p=0.0145) and non-alcohol drinkers (p<0.001).

Conclusion

HCC risk is influenced by ALDH2 genotype, with effects modified by sex and alcohol consumption. Particularly, individuals with the ALDH2 rs671 AA genotype should avoid alcohol consumption, especially males.

Alcohol and its associated liver carcinogenesis

Alcohol consumption is a major cause of cirrhosis and hepatocellular carcinoma (HCC). The prevalence of alcohol-associated hepatocellular carcinoma (aHCC) varies worldwide but is highest in Eastern Europe. Alcohol is the second fastest-growing cause of age-standardized liver cancer mortality with tumors more often diagnosed outside surveillance protocols and at a more advanced stage. Risk factors for aHCC include greater amounts of alcohol consumption, sex, and certain genetic polymorphisms. Smoking, concomitant liver disease, obesity, and diabetes act synergistically in increasing the risk of HCC in alcohol-associated liver disease. Alcohol-related hepatocarcinogenesis results from the complex interactions of several mechanistic pathways. Although not completely understood, underlying mechanisms include acetaldehyde-related hepatotoxicity, oxidative stress, activation of the innate immune system, and alterations of the host microbiome.

Association of Heavy Alcohol Intake and ALDH2 rs671 Polymorphism With Hepatocellular Carcinoma and Mortality in Patients With Hepatitis B Virus-Related Cirrhosis

IMPORTANCE

The role of heavy alcohol intake, aldehyde dehydrogenase 2 gene (ALDH2) rs671 polymorphism, and hepatitis B virus (HBV) infection in hepatocellular carcinoma (HCC) development and mortality remains uncertain.

OBJECTIVE

To investigate the association of heavy alcohol intake, ALDH2 rs671 polymorphism, and HBV infection with HCC development and mortality in patients with cirrhosis.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study enrolled patients with cirrhosis with heavy alcoholism or/and HBV infection from January 2005 to December 2020. Patients were followed up through June 30, 2021. The current data analysis was performed from August 2021 to April 2022. Patients from 3 tertiary hospitals in Taiwan were enrolled.

EXPOSURES

Heavy alcohol intake was defined as consuming more than 80 g of ethanol each day for at least 5 years.

MAIN OUTCOMES AND MEASURES

The primary end point was newly developed HCC. The secondary end point was overall mortality.

RESULTS

Of 1515 patients with cirrhosis (342 with concomitant heavy alcoholism and HBV infection, 796 with HBV infection alone, and 377 with heavy alcoholism alone), 1277 (84.3%) were men, and their mean (SD) age was 49.5 (10.2) years; 746 patients had blood samples collected for ALDH2 rs671 polymorphism analysis. The 10-year cumulative incidences of HCC and mortality were significantly higher in patients with cirrhosis with concomitant HBV infection and alcoholism than in those with HBV infection alone or alcoholism alone. Heavy alcohol intake and the ALDH2 rs671 genotype (GA/AA) were associated with significantly increased risk of HCC and mortality in patients with HBV-related cirrhosis. In patients with cirrhosis with concomitant HBV infection and alcoholism, factors associated with risk of HCC were baseline serum HBV DNA (adjusted hazard ratio [aHR], 3.24; 95% CI, 1.43-7.31), antiviral therapy (aHR, 0.15; 95% CI, 0.05-0.39), alcohol intake (aHR, 1.78; 95% CI, 1.02-3.12), abstinence (aHR, 0.32; 95% CI, 0.18-0.59), and ALDH2 rs671 polymorphism (aHR, 5.61; 95% CI, 2.42-12.90). Factors associated with increased risk of mortality were abstinence (aHR, 0.25; 95% CI, 0.16-0.32), ALDH2 rs671 polymorphism (aHR, 1.58; 95% CI, 1.09-2.26), Child-Pugh class B vs A (aHR, 1.43; 95% CI, 1.13-2.25) and class C vs A (aHR, 1.98; 95% CI, 1.18-3.31), serum albumin (aHR, 0.61; 95% CI, 0.43-0.86), and HCC development (aHR, 1.68; 95% CI, 1.12-2.89).

CONCLUSIONS AND RELEVANCE

These findings suggest that heavy alcohol intake and ALDH2 rs671 polymorphism are associated with significantly increased risk of HCC development and mortality in patients with HBV-related cirrhosis. Patients with these risk factors should be monitored closely for HCC.

A pyroptosis-related gene signature predicts prognosis and immune microenvironment in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a highly malignant tumor with a very poor prognosis. Pyroptosis is an inflammatory form of cell death and plays an important role in cancer development. The prognostic value of pyroptosis-related genes (PRGs) in HCC has not been studied extensively.

METHODS

Unsupervised consensus clustering analysis was performed to identify two subtypes based on the expression profiles of prognostic PRGs in the The Cancer Genome Atlas (TCGA) database, and the differences between the two subtypes were compared. A prognostic model based on four PRGs was established by further least absolute shrinkage and selection operator (LASSO) Cox regression analysis and multivariate Cox regression analysis.

RESULTS

Two subtypes (clusters 1 and 2) were identified by consensus clustering based on prognostic PRGs in HCC. Survival outcomes, biological function, genomic alterations, immune cell infiltration, and immune checkpoint genes were compared between the subtypes. Cluster 2 had a worse survival outcome than cluster 1. Cluster 2 was enriched for hallmarks of cancer progression, TP53 mutation, tumor-promoting immune cells, and immune checkpoint genes, which may contribute to the poor prognosis. A prognostic risk signature that predicted the overall survival (OS) of patients was constructed and validated. Consequently, a risk score was calculated for each patient. Combined with the clinical characteristics, the risk score was found to be an independent prognostic factor for survival of HCC patients. Further analysis revealed that the risk score was closely associated with the levels of immune cell infiltration and the expression profiles of immune checkpoint genes.

CONCLUSIONS

Collectively, our study established a prognostic risk signature for HCC and revealed a significant correlation between pyroptosis and the HCC immune microenvironment.

Alcohol metabolism genes and risks of site-specific cancers in Chinese adults: An 11-year prospective study

Two genetic variants that alter alcohol metabolism, ALDH2-rs671 and ADH1B-rs1229984, can modify oesophageal cancer risk associated with alcohol consumption in East Asians, but their associations with other cancers remain uncertain. ALDH2-rs671 G>A and ADH1B-rs1229984 G>A were genotyped in 150 722 adults, enrolled from 10 areas in China during 2004 to 2008. After 11 years' follow-up, 9339 individuals developed cancer. Cox regression was used to estimate hazard ratios (HRs) for site-specific cancers associated with these genotypes, and their potential interactions with alcohol consumption. Overall, the A-allele frequency was 0.21 for ALDH2-rs671 and 0.69 for ADH1B-rs1229984, with A-alleles strongly associated with lower alcohol consumption. Among men, ALDH2-rs671 AA genotype was associated with HR of 0.69 (95% confidence interval: 0.53-0.90) for IARC alcohol-related cancers (n = 1900), compared to GG genotype. For ADH1B-rs1229984, the HRs of AG and AA vs GG genotype were 0.80 (0.69-0.93) and 0.75 (0.64-0.87) for IARC alcohol-related cancers, 0.61 (0.39-0.96) and 0.61 (0.39-0.94) for head and neck cancer (n = 196) and 0.68 (0.53-0.88) and 0.60 (0.46-0.78) for oesophageal cancer (n = 546). There were no significant associations of these genotypes with risks of liver (n = 651), colorectal (n = 556), stomach (n = 725) or lung (n = 1135) cancers. Among male drinkers, the risks associated with higher alcohol consumption were greater among ALDH2-rs671 AG than GG carriers for head and neck, oesophageal and lung cancers (Pinteraction  < .02). Among women, only 2% drank alcohol regularly, with no comparable associations observed between genotype and cancer. These findings support the causal effects of alcohol consumption on upper aerodigestive tract cancers, with ALDH2-rs671 AG genotype further exacerbating the risks.

Role of ALDH2 in Hepatic Disorders: Gene Polymorphism and Disease Pathogenesis

Aldehyde dehydrogenase 2 (ALDH2) is a key enzyme of alcohol metabolism and it is involved in the cellular mechanism of alcohol liver disease. ALDH2 gene mutations exist in about 8% of the world's population, with the incidence reaching 45% in East Asia. The mutations will result in impairment of enzyme activity and accumulation of acetaldehyde, facilitating the progression of other liver diseases, including non-alcoholic fatty liver diseases, viral hepatitis and hepatocellular carcinoma, through adduct formation and inflammatory responses. In this review, we seek to summarize recent research progress on the correlation between ALDH2 gene polymorphism and multiple liver diseases, with an attempt to provide clues for better understanding of the disease mechanism and for strategy making.