N-Acetyltransferase-2, glutathione S-transferase M1 andT1 genetic polymorphisms, cigarette smoking and hepatocellular carcinoma: A case-control study

Effects of Glutathione S-Transferases (GSTM1, GSTT1 and GSTP1) gene variants in combination with smoking or drinking on cancers: A meta-analysis

BACKGROUND

This meta-analysis aimed to systematically summarize the association between cancer risks and glutathione s-transferases (GSTs) among smokers and drinkers.

METHODS

Literature was searched through PubMed, Web of Science, CNKI, and WANFANG published from 2001 to 2022. Stata was used with fixed-effect model or random-effect model to calculate pooled odds ratios (ORs) and the 95% confidence interval (95% CI). Sensitivity and heterogeneity calculations were performed, and publication bias was analyzed by Begg and Egger's test. Regression analysis was performed on the correlated variables about heterogeneity, and the false-positive report probabilities (FPRP) and the Bayesian False Discovery Probability (BFDP) were calculated to assess the confidence of a statistically significant association.

RESULTS

A total of 85 studies were eligible for GSTs and cancer with smoking status (19,604 cases and 23,710 controls), including 14 articles referring to drinking status (4409 cases and 5645 controls). GSTM1-null had significant associations with cancer risks (for smokers: OR = 1.347, 95% CI: 1.196-1.516, P < .001; for nonsmokers: OR = 1.423, 95% CI: 1.270-1.594, P < .001; for drinkers: OR = 1.748, 95% CI: 1.093-2.797, P = .02). GSTT1-null had significant associations with cancer risks (for smokers: OR = 1.356, 95% CI: 1.114-1.651, P = .002; for nonsmokers: OR = 1.103, 95% CI: 1.011-1.204, P = .028; for drinkers: OR = 1.423, 95% CI: 1.042-1.942, P = .026; for nondrinkers: OR = 1.458, 95% CI: 1.014-2.098, P = .042). Negative associations were found between GSTP1rs1695(AG + GG/AA) and cancer risks among nondrinkers (OR = 0.840, 95% CI: 0.711-0.985, P = .032).

CONCLUSIONS

GSTM1-null and GSTT1-null might be related cancers in combination with smoking or drinking, and GSTP1rs1695 might be associated with cancers among drinkers.

Identification of Potential Prognostic Markers and Key Therapeutic Targets in Hepatocellular Carcinoma Using Weighted Gene Co-Expression Network Analysis: A Systems Biology Approach

BACKGROUND

As the most prevalent form of liver cancer, hepatocellular carcinoma (HCC) ranks the fifth highest cause of cancer-related death worldwide. Despite recent advancements in diagnostic and therapeutic techniques, the prognosis for HCC is still unknown.

OBJECTIVES

This study aimed to identify potential genes contributing to HCC pathogenicity.

MATERIALS AND METHODS

To this end, we examined the GSE39791 microarray dataset, which included 72 HCC samples and 72 normal samples. An investigation of co-expression networks using WGCNA found a highly conserved blue module with 665 genes that were strongly linked to HCC.

RESULTS

APOF, NAT2, LCAT, TTC36, IGFALS, ASPDH, and VIPR1 were the blue module's top 7 hub genes. According to the results of hub gene enrichment, the most related issues in the biological process and KEGG were peroxisome organization and metabolic pathways, respectively. In addition, using the drug-target network, we discovered 19 FDA-approved medication candidates for different reasons that might potentially be employed to treat HCC patients through the modulation of 3 hub genes of the co-expression network (LCAT, NAT2, and VIPR1). Our findings also demonstrated that the 3 scientifically validated miRNAs regulated the co-expression network by the VIPR1 hub gene.

CONCLUSION

We found co-expressed gene modules and hub genes linked with HCC advancement, offering insights into the mechanisms underlying HCC progression as well as some potential HCC treatments.

N-Acetyltransferase 2, Glutathione S-transferase gene polymorphisms and susceptibility to hepatocellular carcinoma in an Algerian population

This study was conducted to investigate the potential association of genetic polymorphisms of glutathione S-transferase M1/T1 (GSTM1, GSTT1), and N-acetyltransferase 2 (NAT2) genes and epidemiological parameters with the risk of HCC in the Algerian population.A case-control study including 132 confirmed HCC patients and 141 cancer-free controls was performed. Genotyping analysis was performed using conventional multiplex PCR and PCR-RFLP. Statistical analysis was performed using the Chi-square test. Logistic regression analysis was used to estimate odds ratios and 95% confidence intervals (95% CI).GSTM1 null and NAT2 slow acetylator genotypes confer an increased risk to HCC (OR =1.88, 95% CI 1.16-3.05; OR =2.30, 95% CI 1.26-4.18, respectively). This association was prevalent in smokers (OR =2.00, 95% CI 1.05-3.8 and OR =2.55, 95% CI 1.22-5.34, respectively). No significant association was observed for GSTT1 null genotype in the contribution to HCC risk (OR =0.76, 95% CI 0.46-1.27).In conclusion, the GSTM1 and NAT2 gene polymorphisms are positively associated with the risk of HCC in older men and especially in smokers.

p53 Mutation at Serine 249 and Its Gain of Function Are Highly Related to Hepatocellular Carcinoma after Smoking Exposure

BACKGROUND

It has been convincingly suggested that a close correlation exists between the incidence of hepatocellular carcinoma (HCC) and cigarette smoking. However, the underlying effect of smoking on HCC is not clear.

METHODS

A binary unconditional logistic regression was used for the data on a total of 300 cases and 612 controls. The approach of functional analysis of separated alleles in yeast and direct sequencing of TP53 mutations were applied to analyze the p53 status in the HCC group. The relationship between p53 mutation at serine 249 (p53-RS) and smoking was assessed. Quantitative reverse transcription PCR was employed for the evaluation to transcriptional activity of p53 and p53-RS.

RESULTS

Smoking was linked to the risk of HCC with an increased dose-response effect. Moreover, among subjects who did not drink, the risks of HCC were significantly increased for smokers between HCC and controls. Besides, there was an increase in the number of HCC in smokers compared to nonsmokers after exclusion of HBV and/or HCV infection. Also, a significant difference was observed in the incidence of p53-RS between smokers and nonsmokers the HCC group. Furthermore, the p53-RS transcriptional activity was significantly increased in tumor tissues.

CONCLUSIONS

It strongly demonstrated that tobacco smoking is positively and independently associated with HCC, which may be attributed to p53-RS and its gain of function.

Association of GSTM1 and GSTT1 Null Deletions and GSTP1 rs1695 Polymorphism with the Risk of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

Context: Hepatocellular carcinoma (HCC), as the most common type of primary liver cancer (accounting for 70% - 90% of all liver cancers), is the seventh most common malignancy worldwide. Glutathione S-transferases (GSTs) are a specific group of enzymes that are responsible for the detoxification of carcinogens. According to the available literature, genetic variations in this group of enzymes may be associated with the risk of HCC. In this study, we aimed to assess the association of GSTM1 and GSTT1 null deletions and GSTP1 rs1695 polymorphism with the risk of HCC. Methods: We systematically searched electronic databases, including PubMed, Scopus, and Web of Science, using appropriate keywords to gather relevant data until March 2019. Studies that met the inclusion criteria were included in the meta-analysis, using either fixed- or random-effects models based on the presence of heterogeneity. Results: This meta-analysis pooled 19 studies for GSTM1 null deletions, 14 studies for GSTT1 null deletions, and five studies for GSTP1 rs1695 polymorphism. In terms of heterogeneity, the pooled odds ratio (OR) was calculated in a random-effects model for both Asian and non-Asian populations. HCC was found to be associated with GSTM1 null deletions (OR = 1.26, 95% CI: 1.00 - 1.58, P = 0.05) and GSTT1 null deletions (OR = 1.39, 95% CI: 1.10 - 1.74, P = 0.005); however, no significant association was found between HCC and GSTP1 rs1695 polymorphism (OR = 1.14, 95% CI: 0.86 - 1.50, P = 0.36). Conclusions: We found that GSTM1 and GSTT1 null deletions increased the risk of HCC; however, the GSTP1 rs1695 polymorphism did not have a similar effect.

GSTM1 and GSTT1 null genotype increase the risk of hepatocellular carcinoma: evidence based on 46 studies

Background

It is well known that hepatocellular carcinoma (HCC) has been one of the most life-threatening diseases all over the world. Plenty of internal and extrinsic factors have been proven to be related to HCC, such as gene mutation, viral hepatitis, and Nitrosamines. Though previous studies demonstrated that glutathione S-transferase (GST) genotypes are associated with HCC, the conclusions are inconsistent. Therefore, we carried on a renewed meta-analysis to expound the connection between the null GSTM1, GSTT1 polymorphisms and the risk of HCC.

Methods

We searched PubMed, Web of Science, Embase, and CNKI databases to select qualified researches which satisfied the inclusion criteria up to July 31, 2018. Finally, we selected 41 articles with 6124 cases and 9781 controls in this meta-analysis. We use ORs and 95% confidence interval (CI) to evaluate the correlation intension between the GSTM1 and GSTT1 null genes and the risk of HCC. All the statistical processes were executed by Stata (version 12.0).

Results

The pooled analysis showed that both GSTM1 null genotypes (OR = 1.37, 95% CI = 1.18–1.59) and GSTT1 null genotypes (OR = 1.43, 95% CI = 1.23–1.66) increased the risk of HCC. And GSTM1–GSTT1 dual-null genotypes also increased the risk of HCC (OR = 1.58, 95% CI = 1.22–2.05). In the subgroup analysis, we obtained significant results among Asians when stratified by race, and the results are GSTM1 null OR = 1.44, 95% CI = (1.22–1.71), GSTT1 null OR = 1.48, 95% CI = (1.25–1.77), GSTM1–GSTT1 null OR = 1.58, 95% CI = (1.19–2.09), while we didn’t obtain significant results among Caucasians or Africans. Stratified analyses on the type of control indicated a higher risk of HCC associated with GSTM1, GSTT1 single null genotypes and GSTM1–GSTT1 dual-null genotypes in healthy people. No evidence of significant connection was discovered in chronic liver disease (CLD) except in GSTT1 single null.

Conclusions

Our study indicated that an individual who carries the GSTM1, GSTT1 single null genotypes and GSTT1–GSTM1 dual-null genotypes is more likely to develop HCC.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0792-3) contains supplementary material, which is available to authorized users.

Loss-of-function mutations in Zn-finger DNA-binding domain of HNF4A cause aberrant transcriptional regulation in liver cancer

Hepatocyte nuclear factors (HNF) are transcription factors that crucially regulate cell-specific gene expression in many tissues, including the liver. Of these factors, HNF4A acts both as a master regulator of liver organogenesis and a tumor suppressor in the liver. In our whole genome sequencing analysis, we found seven somatic mutations (three Zn-finger mutations, three deletion mutants, and one intron mutation) of HNF4A in liver cancers. Interestingly, three out of seven mutations were clustered in its Zn-finger DNA-binding domain; G79 and F83 are positioned in the DNA recognition helix and the sidechain of M125 is sticking into the core of domain. These mutations are likely to affect DNA interaction from a structural point of view. We then generated these mutants and performed in-vitro promoter assays as well as DNA binding assays. These three mutations reduced HNF4 transcriptional activity at promoter sites of HNF4A-target genes. Expectedly, this decrease in transcriptional activity was associated with a change in DNA binding. RNA-Seq analysis observed a strong correlation between HNF4A expression and expression of its target genes, ApoB and HNF1A, in liver cancers. Since knockdown of HNF4A caused a reduction in ApoB and HNF1A expression, possibly loss of HNF4 reduces the expression of these genes and subsequently tumor growth is triggered. Therefore, we propose that HNF4A mutations G79C, F83C, and M125I are functional mutations found in liver cancers and that loss of HNF4A function, through its mutation, leads to a reduction in HNF1A and ApoB gene expression with a concomitant increased risk of liver tumorigenesis.

Screening therapeutic targets of ribavirin in hepatocellular carcinoma

The objective of the present study was to screen the key genes of ribavirin in hepatocellular carcinoma (HCC) and provide novel therapeutic targets for HCC treatment. The mRNA expression datasets of GSE23031 and GSE74656, as well as the microRNA (miRNA) expression dataset of GSE22058 were downloaded from the Gene Expressed Omnibus database. In the GSE23031 dataset, there were three HCC cell lines treated with PBS and three HCC cell lines treated with ribavirin. In the GSE74656 dataset, five HCC tissues and five carcinoma adjacent tissues were selected. In the GSE22058 dataset, 96 HCC tissues and 96 carcinoma adjacent tissues were selected. The differentially expressed genes (DEGs) and differentially expressed miRNAs were identified via the limma package of R. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed with the Database for Annotation, Visualization and Integrated Discovery. The target mRNAs of DEMs were obtained with TargetScan. A total of 559 DEGs (designated DEG-Ribavirin) were identified in HCC cells treated with ribavirin compared with PBS and 632 DEGs (designated DEG-Tumor) were identified in HCC tissues compared with carcinoma adjacent tissues. A total of 220 differentially expressed miRNAs were identified in HCC tissues compared with carcinoma adjacent tissues. In addition, 121 GO terms and three KEGG pathways of DEG-Ribavirin were obtained, and 383 GO terms and 25 KEGG pathways of DEG-Tumor were obtained. A total of five key miRNA-mRNA regulated pairs were identified, namely miR-183→CCNB1, miR-96→DEPDC1, miR-96→NTN4, miR-183→NTN4 and miR-145→NTN4. The present study indicated that certain miRNAs (including miR-96, miR-145 and miR-183) and mRNAs (including NAT2, FBXO5, CCNB1, DEPDC1 and NTN4) may be associated with the effects of ribavirin on HCC. Furthermore, they may provide novel therapeutic targets for HCC treatment.

The Interaction of Smoking with Gene Polymorphisms on Four Digestive Cancers: A Systematic Review and Meta-Analysis

The main purpose of this study was to perform a meta-analysis to assess the interaction between smoking and nine genes (GSTM1, GSTT1, GSTP1, CYP1A1, NAT2, SULT1A1, hOGG1, XRCC1 and p53) on colorectal cancer, gastric cancer, liver cancer and oesophageal cancer. Published articles from the PubMed, ISI and EMBASE databases were retrieved. A total of 67 case-control studies or nested case-control studies were identified for the analysis. The pooled jodds ratio (OR) with 95% confidence interval (CI) was calculated using the random effect model. The overall study showed that the GSTM1 polymorphism was associated with the risk of the four digestive cancers among Asian population (OR 1.284, 95% CI: 1.122-1.470, p: 0). Subgroup analyses by cancer site showed that GSTM1 null genotype increased the gastric cancer risk in total population (OR 1.335, 95% CI: 1.145-1.556, p: 0). However, the association of GSTM1 null genotype with the oesophageal cancer risk was found in smokers (OR 1.382, 95% CI: 1.009-1.894, p:0.044), but not in non-smokers (OR 1.250, 95% CI: 0.826-1.891, p:0.290). Moreover, smokers with the CYP1A1 IIe462Val polymorphism were at an increased cancer risk in Asian population (OR=1.585, 95% CI 1.029-2.442, p: 0.037). None of the other gene-smoking interactions was observed in the above cancers. This meta-analysis reveals two potential gene-smoking interactions, one is between smoking and GSTM1 on oesophageal cancer, and the other is between smoking and CYP1A1 IIe462Val on the four cancers in Asian population. Future studies need to be conducted to verify the conclusions.

Cigarette smoking as a risk factor for the development of and mortality from hepatocellular carcinoma: An updated systematic review of 81 epidemiological studies

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and its incidence has increased during the past decade. While hepatitis B and C virus infections and alcohol were established risk factors, the impact of smoking on the incidence and mortality of HCC was needed to be confirmed.

METHODS

We reviewed cohort and case-control studies evaluating the association between cigarette smoking and incidence and mortality of HCC from MEDLINE and Google Scholar. We also checked reference lists of original studies and review articles manually for cross-references up to February 2016. We extracted the relevant information on participant characteristics and study outcomes, as well as information on the methodology of the studies. We also assessed the quality of the included trials using critical appraisal skills program checklists. Meta-analysis was performed by using RevMan 5.3 software.

RESULTS

A total of 81 studies were included in the systematic review. Pooled OR for HCC development with current smokers was 1.55 (95% CI: 1.46 to 1.65; P < 0.00001). Pooled OR for HCC development with former smokers was 1.39 (95% CI: 1.26 to 1.52; P < 0.00001) and pooled OR for HCC development with heavy smokers was 1.90 (95% CI: 1.68 to 2.14; P < 0.00001). Pooled OR for the mortality of current smokers with HCC was 1.29 (95% CI: 1.23 to 1.34; P < 0.00001); and for former smokers with HCC, it was 1.20 (95% CI: 1.00 to 1.42; P = 0.04).

CONCLUSIONS

Cigarette smoking increases the incidence and mortality of HCC. Further studies are needed to evaluate possible impact of quitting smoking on decreasing this risk.

Aflatoxin levels in chronic hepatitis B patients with cirrhosis or hepatocellular carcinoma in Balıkesir, Turkey

Aflatoxins, the secondary metabolites produced by species of naturally occurring Aspergilli, are commonly found in food such as cereals, dried fruits and juice, wine, beer and spices. They are hepatotoxic and are well known human carcinogens based on evidence from human studies. Aflatoxins are an environmental risk factor for the development of hepatocellular carcinoma (HCC). Chronic hepatitis B-infected patients are at increased risk of cirrhosis, hepatic failure and liver cancer. This study was designed to determine the serum aflatoxin B1 (AFB1 ), aflatoxin B2 (AFB2 ), aflatoxin G1 (AFG1 ) and aflatoxin G2 (AFG2 ) concentrations using high-pressure liquid chromatography (HPLC) in hepatitis B-infected patients with or without cirrhosis and liver cancer, alongside healthy controls in Balıkesir, Turkey. The mean AFB1 and total AF levels in patients without liver cancer and cirrhosis were significantly higher than healthy controls. The mean AFB1 and total AF levels in patients with chronic hepatitis B and HCC were significantly higher than infected patients with or without cirrhosis. These results suggest that patients with chronic hepatitis B who are exposed to AFs are at increased risk for developing HCC, which might be prevented by reducing consumption of contaminated foods.

Alcohol consumption and liver cancer risk: a meta-analysis

PURPOSE

Alcohol is a confirmed risk factor of liver cancer. Yet, its dose-response function and synergistic effects with other risk factors remain unclear.

METHODS

We performed a meta-analysis on publications up to May 2014. A total of 112 publications were identified. The meta-relative risk (mRR) and the dose-response trend were calculated. Tests for heterogeneity, publication bias, and sensitivity analyses were performed. The synergy index (SI) was recorded or calculated, whenever possible.

RESULTS

Compared to individuals who never drank or drank at very low frequencies, the mRR for ever drinkers was 1.29 (95% confidence interval, CI 1.16-1.42) and 1.46 (95% CI 1.27-1.65) for case-control studies, and 1.07 (95% CI 0.87-1.27) for cohort studies. Being a current drinker was associated with an increased liver cancer risk in case-control studies (mRR = 1.55, 95% CI 0.38-2.73), but not in cohort studies (mRR = 0.86, 95% CI 0.74-0.97). The dose-response relation between alcohol and liver cancer was apparent with RR = 1.08 (95% CI 1.04-1.11) for 12 g/day (~1 drink), 1.54 (95% CI 1.36-1.74) for 50 g/day, 2.14 (95% CI 1.74-2.62) for 75 g/day, 3.21 (95% CI 2.34-4.40) for 100 g/day, and 5.20 (95% CI 3.25-8.29) for 125 g/day of alcohol consumption. There were synergistic effects of alcohol consumption with hepatitis (S = 2.14, 95% CI 1.31-2.98) and with diabetes (S = 3.57, 95% CI 2.29-4.84) on the risk of liver cancer, although this may be subject to publication bias.

CONCLUSION

Overall, one alcoholic drink per day (~12 g/day) may be associated with a 1.1 times higher liver cancer risk. Further studies on the synergistic effects of alcohol consumption and other major risk factors are warranted.

Interactive effect of glutathione S-transferase M1 and T1 polymorphisms on hepatocellular carcinoma

Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) have been involved in the risk of hepatocellular carcinoma (HCC). However, the interactive effect of GSTM1 and GSTT1 has not been reported previously. The aim of this work was to investigate the interaction and synergism of their variants. We identified nine publications including 1,085 cases and 2,396 controls containing both GSTM1 and GSTT1, and the bi-factor variance analysis of equal repeated test, binary class logistic regression analysis, meta-analysis and probability method were used in this analysis. Data showed there was no interaction between GSTM1 and GSTT1 null genotype variation in HCC development. In addition, individuals with at least one null genotype of GSTM1 and GSTT1 had higher susceptibility to HCC (OR = 2.99, 95 % CI 2.21-4.02). In the control group, the probability of individuals with at least one null genotype of GSTM1 and GSTT1 was 0.6624, while in the case group, the probability to develop HCC with at least one null genotype of GSTM1 and GSTT1 increased to 0.1760, which was considered as the changing characteristics of HCC occurrence in Chinese population. Our result suggests that there would be no direct interaction of GSTM1 and GSTT1 genotype in HCC risk. We speculate that GSTM1 and GSTT1 genotype variations have their own independent function in HCC development and may mutate independently to cause HCC. The synergism variants of the two genes in HCC development have bigger risk in Chinese population.

Impact of the genes UGT1A1, GSTT1, GSTM1, GSTA1, GSTP1 and NAT2 on acute alcohol-toxic hepatitis

Alcohol metabolism causes cellular damage by changing the redox status of cells. In this study, we investigated the relationship between genetic markers in genes coding for enzymes involved in cellular redox stabilization and their potential role in the clinical outcome of acute alcohol-induced hepatitis. Study subjects comprised 60 patients with acute alcohol-induced hepatitis. The control group consisted of 122 healthy non-related individuals. Eight genetic markers of the genes UGT1A1, GSTA1, GSTP1, NAT2, GSTT1 and GSTM1 were genotyped. GSTT1 null genotype was identified as a risk allele for alcohol-toxic hepatitis progression (OR 2.146, P=0.013). It was also found to correlate negatively with the level of prothrombin (β= −11.05, P=0.037) and positively with hyaluronic acid (β=170.4, P=0.014). NAT2 gene alleles rs1799929 and rs1799930 showed opposing associations with the activity of the biochemical markers γ-glutamyltransferase and alkaline phosphatase; rs1799929 was negatively correlated with γ-glutamyltransferase (β=−261.3, P=0.018) and alkaline phosphatase (β= −270.5, P=0.032), whereas rs1799930 was positively correlated with Γ-glutamyltransferase (β=325.8, P=0.011) and alkaline phosphatase (β=374.8, P=0.011). Enzymes of the glutathione S-transferase family and NAT2 enzyme play an important role in the detoxification process in the liver and demonstrate an impact on the clinical outcome of acute alcohol-induced hepatitis.

Hepatitis C virus related hepatocellular carcinoma: a case control study from India

Infection with hepatitis C virus (HCV) is a major risk factor for hepatocellular carcinoma (HCC) in India. The study was designed to investigate the clinical and molecular profiles of HCV related HCC cases in Indian patients. In a prospective study, 68 HCV related HCC, 55 HCV related chronic hepatitis, and 68 HCV related patients with cirrhosis were included. Glutathione S-transferase gene polymorphism was analyzed in all the cases. The sex ratios were 5.18:1, 1.39:1, and 0.83:1 with mean age of 50.57 ± 12.47, 39.41 ± 13.34, and 46.08 ± 15.06 years, respectively, in three groups. Amongst the HCV related HCC cases seen in India, 49.2% (30 out of 68) were with Okuda stage I while 34.4% (21 out of 68) cases were classified as stage II. Older age, poor standards of living, HCV genotype 4, smoking, and null genotypes of GST were the risk factors associated significantly with the development of HCC. In 55.9% cases (38 out of 68) the size of the tumor was ≥5 cm while in 38.2% cases (26 out of 68) the size was between 2 and 5 cm, indicating an advanced stage of the disease at presentation.

Joint effect of polymorphism in the N-acetyltransferase 2 gene and smoking on hepatocellular carcinoma

The N-acetyltransferase 2 gene (NAT2) has been implicated in the development of hepatocellular carcinoma (HCC). However, the results have been inconsistent. In this study, the authors performed a meta-analysis to clarify the association between NAT2 polymorphism and HCC risk. Published literatures from PubMed, EMBASE, CNKI, and Wan Fang Data were retrieved. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed- or random-effects model. Eight studies including 1,084 HCC cases and 1,682 controls were identified for the data analysis. The overall result showed that there was no statistically significant association between NAT2 genotypes and HCC risk (slow acetylation vs. rapid/intermediate acetylation: OR01.03, 95% CI 0.86–1.24). In the stratified analyses, NAT2 genotypes were also not significantly associated with HCC risk among both Europeans (OR01.11, 95% CI 0.86–1.43) and East Asians (OR01.01, 95% CI 0.65–1.56). Further subgroup analyses based on the smoking status showed that the effect size was statistically significant among the smokers (OR02.09, 95% CI 1.07–4.09), but not among those who never smoked (OR01.26, 95% CI 0.88–1.82). The present meta-analysis indicated that NAT2 genotypes were not associated with increased risk of HCC among the overall population but increased the risk of HCC among the smokers.

Reduced 4-aminobiphenyl-induced liver tumorigenicity but not DNA damage in arylamine N-acetyltransferase null mice

The aromatic amine 4-aminobiphenyl (ABP) is a liver procarcinogen in mice, requiring enzymatic bioactivation to exert its tumorigenic effect. To assess the role of arylamine N-acetyltransferase (NAT)-dependent acetylation capacity in the risk for ABP-induced liver tumors, we compared 1-year liver tumor incidence following the postnatal exposure of wild-type and NAT-deficient Nat1/2(-/-) mice to ABP. At an ABP exposure of 1200 nmol, male Nat1/2(-/-) mice had a liver tumor incidence of 36% compared to 69% in wild-type males, and at 600 nmol there was a complete absence of tumors compared to 60% in wild-type mice. Only one female wild-type mouse had a tumor using this exposure protocol. However, levels of N-deoxyguanosin-8-yl-ABP-DNA adducts did not correlate with either the strain or sex differences in tumor incidence. These results suggest that female sex and NAT deficiency reduce risk for ABP-induced liver tumors, but by mechanisms unrelated to differences in DNA-damaging events.

Role of aflatoxin B1 as a risk for primary liver cancer in north Indian population

OBJECTIVES

The present study was designed to determine whether aflatoxin B1 (AFB1) exposure has any role to play in hepatocellular carcinoma (HCC) patients from northern India.

DESIGN AND METHODS

A total of 266 HCC patients and 251 patients of chronic liver disease without-HCC were enrolled into the study. All samples were screened for serological markers for hepatitis B and C infections and levels of AFB1 in food and urine samples.

RESULTS

A threefold (OR=3.43) and five-fold (OR=5.47) increased risk of HCC was observed amongst HBV infection and AFB1-levels in food and urine samples, respectively. However, a non-significant risk was observed with respect to HCV infection (OR=1.27) and alcohol consumption (OR=1.18). A threefold (OR=3.15) increased risk of HCC was observed amongst cases of non-viral etiology with respect to urinary AFB1.

CONCLUSION

The data provides an exposure and disease risk information for establishing intervention studies to diminish the impact of aflatoxin exposure in Indian population.

Molecular characteristics of non-cancerous liver tissue in non-B non-C hepatocellular carcinoma

Although chronic infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) are the most important risk factors for the development of hepatocellular carcinoma (HCC) worldwide, the proportion of HCC patients negative for the hepatitis B surface antigen and hepatitis C antibody, so-called "non-B non-C HCC", is rapidly increasing, especially in Japan. The background liver diseases of non-B non-C HCC patients can be multifactorial, including occult HBV infection and non-alcoholic steatohepatitis. It is reasonable to investigate the non-cancerous liver tissues to identify the potential molecular mechanisms responsible for the processes of hepatocarcinogenesis of non-B non-C HCC. However, to date, only a few studies have focused on this research concept based on the idea of "field cancerization". This review highlights the potential importance of the molecular analysis of non-cancerous liver tissues to clarify the molecular characteristics in patients with non-B non-C HCC. A better understanding of the molecular mechanisms underlying the individual predisposition to non-B non-C HCC will lead to improvements in the prevention, early diagnosis and treatment of this neoplastic disease.

Epidemiology of primary and secondary liver cancers

Primary liver cancer is the sixth most common cancer worldwide with a wide geographic distribution. The incidence of primary liver cancer is increasing and there is still a higher prevalence in developing countries. Early recognition remains an obstacle and lack of it results in poor outcomes for hepatocellular carcinoma (HCC), the most prevalent primary liver cancer, and cholangiocarcinoma. The most common risk factors associated with HCC are hepatitis B and chronic hepatitis C infections, alcohol use, smoking, and aflatoxin exposure. Emerging risk factors such as obesity might play an important role in the future because of the increasing prevalence of this condition.

Null genotypes of GSTM1 and GSTT1 contribute to hepatocellular carcinoma risk: evidence from an updated meta-analysis

BACKGROUND & AIMS

Studies investigating the associations between glutathione S-transferase (GST) genetic polymorphisms and hepatocellular carcinoma (HCC) risk have reported controversial results. Thus, a meta-analysis was performed to clarify the effects of GSTM1 and GSTT1 polymorphisms on HCC risk.

METHODS

We identified 132 relevant records through a literature search up to November 22, 2009, and 24 individual case-control studies from 23 publications were finally included, involving a total of 3349 HCC cases and 5609 controls. Subgroup analyses were performed by ethnicity, or by area according to the incidence rate and hepatitis virus status.

RESULTS

Analyses of total relevant studies showed an increased HCC risk was significantly associated with null genotypes of GSTM1 (OR=1.26, 95% CI 1.03-1.54, p(OR)=0.027) and GSTT1 (OR=1.28, 95% CI 1.09-1.51, p(OR)=0.002). In addition, the GSTM1-GSTT1 interaction analysis showed that the dual null genotype of GSTM1/GSTT1 was significantly associated with increased HCC risk (OR=1.89, 95% CI 1.38-2.60, p(OR)<0.001). Subgroup analyses showed that the associations above were still statistically significant in Asians (p(GSTM1)=0.017, p(GSTT1)=0.001, p(Dual null genotype)<0.001), high-rate areas (p(GSTM1)=0.012, p(GSTT1)=0.006, p(Dual null genotype)<0.001), and HBV-dominant areas (p(GSTM1)=0.003, p(GSTT 1)=0.003, p(Dual null genotype)<0.001).

CONCLUSIONS

This meta-analysis suggests null genotypes of GSTM1 and GSTT1 are both associated with increased HCC risk in Asians, and individuals with the dual null genotype of GSTM1/GSTT1 are particularly susceptible to developing HCC.

Independent and additive interactive effects among tumor necrosis factor-alpha polymorphisms, substance use habits, and chronic hepatitis B and hepatitis C virus infection on risk for hepatocellular carcinoma

We conducted a case-control study to assess the roles of tumor necrosis factor (TNF)-alpha polymorphisms, substance use habits, and chronic hepatitis B virus (HBV)/hepatitis C virus (HCV) infection on the risk for hepatocellular carcinoma (HCC). We enrolled 200 pairs of sex- and age-matched patients with HCC and unrelated healthy controls. TNF-alpha polymorphisms were detected with polymerase chain reaction and direct sequencing. Serum hepatitis B surface antigen (HBsAg) and antibodies to HCV (anti-HCV) were detected. We used a structured questionnaire to obtain information about substance use habits.Multivariate analysis indicated that TNF308.2 allele (odds ratio [OR], 3.23; p = 0.011), habitual betel quid chewing (OR, 3.70; p = 0.011), HBsAg (OR, 23.62; p = 0.0001), and anti-HCV (OR, 38.73; p = 0.0001) were independent risk factors for HCC. Having at least 2 substance use habits was associated with risk for HCC. The more substance use habits, the higher the OR for HCC (p(for trend) = 0.0001). There were additive interactions among TNF308.2 allele, substance use habits, and chronic HBV/HCV infection. Multivariate analysis indicated that TNF308.2 allele (p = 0.001), cigarette smoking (p = 0.0001), and alcohol drinking (p = 0.0001) were independent risk factors for habitual betel quid chewing. Moreover, patients harboring the TNF308.2 allele and/or those with habits of substance use had low serum albumin concentration and platelet count (each p = 0.0001). In conclusion, there are independent and additive interactive effects among the TNF308.2 allele, substance use habits, and chronic HBV/HCV infection on the risk for HCC. Substance use habits or carrying the TNF308.2 allele correlates with disease severity and hepatic fibrosis, which may contribute to higher risks for HCC.

Meta-analysis of epidemiologic studies on cigarette smoking and liver cancer

BACKGROUND

Whereas the International Agency for Research on Cancer (IARC) Monograph concluded that the evidence for the relationship between cigarette smoking and liver cancer is sufficient, the US Surgeon General's report summarized the data as suggestive but not sufficient.

METHODS

A meta-analysis of previous epidemiologic studies may help to clarify the potential association. We identified 38 cohort studies and 58 case-control studies in a systematic literature search for studies on liver cancer and cigarette smoking. The meta-relative risk (mRR) of liver cancer and dose-response trends were calculated. Tests for heterogeneity, publication bias assessment and influence analyses were performed.

RESULTS

Compared with never smokers, the adjusted mRR was 1.51 [95% confidence interval (CI) 1.37-1.67] for current smokers and 1.12 (95% CI 0.78-1.60) for former smokers. The increased liver cancer risk among current smokers appeared to be consistent in strata of different regions, study designs, study sample sizes and publication periods.

CONCLUSION

The results of our meta-analysis show that tobacco smoking is associated with liver cancer development, which supports the conclusion by the IARC Monograph. This conclusion has an important public health message for areas with high smoking prevalence and high liver cancer incidence such as China.

Interaction between cytochrome P450 1A2 genetic polymorphism and cigarette smoking on the risk of hepatocellular carcinoma in a Japanese population

Limited epidemiological evidence suggests that genetic polymorphisms of drug-metabolizing enzymes such as cytochrome P450 (CYP), glutathione S-transferase (GST) and N-acetyltransferase (NAT) may be involved in tobacco-related hepatocarcinogenesis. We conducted a case-control study, including 209 incident cases with hepatocellular carcinoma (HCC) and two different control groups [275 hospital controls and 381 patients with chronic liver disease (CLD) without HCC], to investigate whether CYP1A1, CYP1A2, CYP2A6, CYP2E1, GSTM1 and NAT2 polymorphisms are related to the risk of HCC with any interaction with cigarette smoking. Overall, no significant associations with HCC were observed for any genotypes against either control group. However, we found a significant interaction (P = 0.0045) between CYP1A2 -3860G>A polymorphism and current smoking on HCC risk when we compared HCC cases with CLD patients; adjusted odds ratios [ORs; and 95% confidence intervals (CIs)] for G/A and A/A genotypes relative to G/G genotype were 0.28 (0.12-0.66) and 0.18 (0.04-0.94), respectively, among current smokers (P trend = 0.002), as compared with 1.28 (0.80-2.06) and 0.76 (0.34-1.71), respectively, among never/former smokers (P trend = 0.96). Similarly, in CYP1A2 G/G genotype, significant risk increase was observed for current smoking (OR = 4.08, 95% CI = 2.02-8.25) or more recent cigarette use (e.g. pack-years during last 5 years, P trend = 0.0003) but not in G/A and A/A genotypes combined (OR for current smoking = 1.39, 95% CI = 0.63-3.03; P trend for pack-years during last 5 years = 0.40). These results suggest that the CYP1A2 -3860G>A polymorphism modifies the smoking-related HCC risk among CLD patients.

DNA-repair and carcinogen-metabolising enzymes genetic polymorphisms as an independent risk factor for hepatocellular carcinoma in Caucasian liver-transplanted patients

We studied polymorphisms of three genes, UDP-glucuronosyltransferase1A7 (UGT1A7), Glutathione-S-transferaseM1 (GSTM1) and X-Ray Cross Complementing group 1 (XRCC1), involved in detoxification of xenobiotics or DNA-repair in a population of 133 liver-transplanted patients, including 56 patients with hepatocellular carcinoma (HCC) and 77 without HCC, and in 89 healthy controls originating from the south of France. Multiple logistic regression analysis showed that, among liver-transplanted patients, interactions between XRCC1-G/G or -G/A and GSTM1-nul polymorphisms were independently associated with hepatocellular carcinoma (p interaction=0.027) concurrently with increasing age (p<0.001), male sex (p=0.037) and chronic hepatitis B or C virus infection (p=0.018 and p=0.001 respectively). On the contrary, no relationship was observed between UGT1A7 polymorphisms considered alone or in interaction with GSTM1 or XRCC1 polymorphisms and HCC. This suggests that concomitant impaired metabolism of carcinogenic compounds and impaired DNA-repair function play an important role in liver carcinogenesis in high-risk cirrhotic patients originating from the south of France.

Southern Europe as an example of interaction between various environmental factors: a systematic review of the epidemiologic evidence

Hepatitis B virus (HBV), hepatitis C virus (HCV) and alcohol consumption are major causes of hepatocellular carcinoma (HCC) worldwide. We performed a systematic review of epidemiologic studies carried out on HCC aetiology in Southern Europe, an area with an intermediate-high prevalence of these agents as well as of putative risk factors such as tobacco smoking, diabetes and obesity. To retrieve the articles, we performed a Medline search for titles and abstracts of articles. After the Medline search, we reviewed the papers and reference lists to identify additional articles. A synergism between HCV infection and HBV infection, overt (hepatitis B virus antigen (HbsAg) positivity) or occult (HBsAg negativity with presence of HBV DNA in liver or serum), is suggested by the results of some studies. The pattern of the risk for HCC due to alcohol intake shows a continuous dose-effect curve without a definite threshold, although most studies found that HCC risk increased only for alcohol consumption above 40-60 g of ethanol per day. Some evidence supports a positive interaction of alcohol intake probably with HCV infection and possibly with HBV infection. A few studies found that coffee has a protective effect on HCC risk due to various risk factors. Some data also support a role of tobacco smoking, diabetes and obesity as single agents or preferably co-factors in causing HCC. In countries with a relatively high alcohol consumption and intermediate levels of HCV and HBV infections (1-3% of population infected by each virus), such as Mediterranean countries, the three main risk factors together account for about 85% of the total HCC cases, leaving little space to other known risk factors, such as haemochromatosis, and to new, still unrecognised, factors as independent causes of HCC.

Glutathione S-transferase M1 and T1 genetic polymorphisms are not related to the risk of hepatocellular carcinoma: a study in the Spanish population

Glutathione S-transferases constitute a superfamily of enzymes that catalyse the inactivating conjugation of endogenous and environmental substrates involved in the pathogenesis of hepatocellular carcinoma (HCC) and glutathione. Genes encoding either glutathione S-transferase Mu-1 or Theta-1 (GSTM1 and GSTT1, respectively) isoforms are polymorphic. Homozygotes for the mutated inactive alleles of each gene are devoid of any specific enzymatic activity (null genotypes). Our aim was to investigate whether individuals with null GST genotypes have a higher risk of developing HCC. A total of 184 Caucasian Spanish patients with a diagnosis of HCC and 329 healthy controls of the same ethnic origin were included. Polymorphisms in GSTM1 and GSTT1 genes were identified through multiplex polymerase chain reactions, and the dihydrofolate reductase (DHFR) gene was used as internal control. No differences were found between the frequencies of GSTM1 (47.8% versus 45.3%) and GSTT1 (28.8% versus 23.1%) null genotypes in cases and controls, respectively, nor in the proportion of carriers of two, one or no active genotypes. Gender, age at diagnosis, tobacco use, chronic infection with hepatitis B or C virus and alcohol abuse did not influence these results. In conclusion, polymorphisms in GSTM1 and GSTT1 genes are not related to the incidence of HCC in a high-risk Spanish population.