Polymorphisms in metabolic genes, their combination and interaction with tobacco smoke and alcohol consumption and risk of gastric cancer: a case-control study in an Italian population

Risk factors and a nomogram for predicting local recurrence in adult patients with early gastric cancer after endoscopic submucosal dissection

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) is an effective treatment method for early gastric cancers. The aim of this study was to evaluate the risk factors of recurrence for patients with early gastric cancer after ESD and construct a nomogram for predicting recurrence.

METHODS

A retrospective observational study was conducted on patients with early gastric cancer who underwent ESD at Beijing Friendship Hospital between 2013 and 2018. The risk factors of gastric cancer recurrence after ESD were analyzed by univariate and multivariate Cox regression.

RESULTS

A total of 238 patients with a median follow-up period of 70.5-month were enrolled in the study. Risk factors for recurrence included diabetes (HR = 3.68), alcohol consumption history (HR = 5.73), complications (HR = 5.22), lymphatic invasion (HR = 13.09) and multiple lesions (HR = 4.34). The analysis of the receiver operating characteristic curve, calibration curve, and model consistency index demonstrates that the graphical representation exhibits a good predictive capability.

CONCLUSIONS

Based on identified risk factors, this study developed the first nomogram with high accuracy to predict the recurrence of early gastric cancer after ESD. This model offers valuable guidance to clinicians for identifying high-risk patient groups and planning more intensive follow-up strategies.

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.

Dose-response association between cigarette smoking and gastric cancer risk: a systematic review and meta-analysis

This study aims at providing an accurate and up-to-date quantification of the dose-response association between cigarette smoking and gastric cancer (GC) risk, overall and by subsite. We conducted a systematic review and meta-analysis of case-control and cohort studies on the association between cigarette smoking and GC risk published up to January 2023. We estimated pooled relative risks (RR) of GC and its subsites according to smoking status, intensity, duration, and time since quitting. Among 271 eligible articles, 205 original studies were included in this meta-analysis. Compared with never smokers, the pooled RR for GC was 1.53 (95% confidence interval; CI 1.44-1.62; n = 92) for current and 1.30 (95% CI 1.23-1.37; n = 82) for former smokers. The RR for current compared with never smokers was 2.08 (95% CI 1.66-2.61; n = 21) for gastric cardia and 1.48 (95% CI 1.33-1.66; n = 8) for distal stomach cancer. GC risk nonlinearly increased with smoking intensity up to 20 cigarettes/day (RR:1.69; 95% CI 1.55-1.84) and levelled thereafter. GC risk significantly increased linearly with increasing smoking duration (RR: 1.31; 95% CI 1.25-1.37 for 20 years) and significantly decreased linearly with increasing time since quitting (RR: 0.65; 95% CI 0.44-0.95 for 30 years since cessation). The present meta-analysis confirms that cigarette smoking is an independent risk factor for GC, particularly for gastric cardia. GC risk increases with a low number of cigarettes up to 20 cigarettes/day and increases in a dose-dependent manner with smoking duration.

Wood cookstove use is associated with gastric cancer in Central America and mediated by host genetics

Biomass cookstove food preparation is linked to aero-digestive cancers, mediated by ingested and inhaled carcinogens (e.g., heterocyclic amines, and polycyclic aromatic hydrocarbons). We investigated the association between gastric adenocarcinoma, wood cookstove use, H. pylori CagA infection and risk modification by variants in genes that metabolize and affect the internal dose of carcinogens. We conducted a population-based, case-control study (814 incident cases, 1049 controls) in rural Honduras, a high-incidence region with a homogeneous diet and endemic H. pylori infection, primarily with the high-risk CagA genotype. We investigated factors including wood cookstove use, H. pylori CagA serostatus, and 15 variants from 7 metabolizing genes, and the interactions between wood stove use and the genetic variants. Male sex (OR 2.0, 1.6-2.6), age (OR 1.04, 1.03-1.05), wood cookstove use (OR 2.3, 1.6-3.3), and CagA serostatus (OR 3.5, 2.4-5.1) and two SNPs in CYP1B1 (rs1800440 and rs1056836) were independently associated with gastric cancer in multivariate analysis. In the final multivariate model, a highly significant interaction (OR 3.1, 1.2-7.8) was noted between wood cookstove use and the rs1800440 metabolizing genotype, highlighting an important gene-environment interaction. Lifetime wood cookstove use associates with gastric cancer risk in the high-incidence regions of Central America, and the association is dependent on the rs1800440 genotype in CYP1B1. H. pylori CagA infection, wood cookstove use and the rs1800440 genotype, all of which are highly prevalent, informs who is at greatest risk from biomass cookstove use.

The impact of IDH and NAT2 gene polymorphisms in acute myeloid leukemia risk and overall survival in an Arab population: A case-control study

Acute myeloid leukemia (AML) is a malignancy of the myeloid cells due to the clonal and malignant proliferation of blast cells. The etiology of AML is complex and involves environmental and genetic factors. Such genetic aberrations include FLT3, DNMT3, IDH1, IDH2, NAT2, and WT. In this study, we analyzed the relationship between five, not previously studied in any Arab population, single nucleotide polymorphisms (SNPs) and the risk and overall survival of AML in Jordanian patients. The SNPs are NAT2 (rs1799930 and rs1799931), IDH1 (rs121913500), and IDH2 (rs121913502 and rs1057519736). A total number of 30 AML patients and 225 healthy controls were included in this study. Females comprised 50% (n = 15) and 65.3% (n = 147) of patients and controls, respectively. For AML patients (case group) Genomic DNA was extracted from formalin-fixed paraffin-embedded tissues and from peripheral blood samples for the control subjects group. Genotyping of the genetic polymorphisms was conducted using a sequencing protocol. Our study indicates that NAT2 rs1799930 SNP had a statistically significant difference in genotype frequency between cases and controls (p = 0.023) while IDH mutations did not correlate with the risk and survival of AML in the Jordanian population. These results were also similar in the TCGA-LAML cohorts with the notable exception of the rare NAT2 mutation. A larger cohort study is needed to further investigate our results.

Smoking history and severe atrophic gastritis assessed by pepsinogen are risk factors for the prevalence of synchronous gastric cancers in patients with gastric endoscopic submucosal dissection: a multicenter prospective cohort study

BACKGROUND

No studies have evaluated the relationship between lifestyle and synchronous gastric cancers (SGCs) in patients with endoscopic submucosal dissection (ESD) for early gastric cancers (EGCs). Using data from the Tohoku gastrointestinal (GI) study, we aimed to identify factors associated with SGCs.

METHODS

Tohoku GI study is a multicenter prospective cohort study investigating the relationship between lifestyle and metachronous gastric cancers. Patients who had a schedule to undergo ESD for primary EGCs were enrolled. We used logistic regression analysis to examine the relationship of 15 candidate factors, including lifestyle, with the prevalence of SGCs in this study.

RESULTS

Of 850 patients between 2016 and 2019, 16.0% (136 patients) had SGCs. In multivariate analysis, smoking history (odds ratio [OR], 1.93; p = 0.048) and severe atrophic gastritis assessed by pepsinogen (OR, 1.92; p = 0.004) were risk factors for the prevalence of SGCs. Regarding smoking, current smoking (OR, 2.33; p = 0.021), but not former smoking (OR, 1.76; p = 0.098), was a significant risk factor for its prevalence. In the stratified analysis, severe atrophic gastritis assessed by pepsinogen was a risk factor in patients without Helicobacter pylori (H. pylori) eradication (OR, 2.10; p = 0.002), but not a risk factor in those with H. pylori eradication (OR, 0.75; p = 0.737).

CONCLUSION

Smoking history was a risk factor for the prevalence of SGCs in patients with ESD for EGCs, and severe atrophic gastritis assessed by pepsinogen was also a risk factor when H. pylori was not eradicated.

Tea consumption and gastric cancer: a pooled analysis from the Stomach cancer Pooling (StoP) Project consortium

BACKGROUND

Evidence from epidemiological studies on the role of tea drinking in gastric cancer risk remains inconsistent. We aimed to investigate and quantify the relationship between tea consumption and gastric cancer in the Stomach cancer Pooling (StoP) Project consortium.

METHODS

A total of 9438 cases and 20,451 controls from 22 studies worldwide were included. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) of gastric cancer for regular versus non-regular tea drinkers were estimated by one and two-stage modelling analyses, including terms for sex, age and the main recognised risk factors for gastric cancer.

RESULTS

Compared to non-regular drinkers, the estimated adjusted pooled OR for regular tea drinkers was 0.91 (95% CI: 0.85-0.97). When the amount of tea consumed was considered, the OR for consumption of 1-2 cups/day was 1.01 (95% CI: 0.94-1.09) and for >3 cups/day was 0.91 (95% CI: 0.80-1.03). Stronger inverse associations emerged among regular drinkers in China and Japan (OR: 0.67, 95% CI: 0.49-0.91) where green tea is consumed, in subjects with H. pylori infection (OR: 0.68, 95% CI: 0.58-0.80), and for gastric cardia cancer (OR: 0.64, 95% CI: 0.49-0.84).

CONCLUSION

Our results indicate a weak inverse association between tea consumption and gastric cancer.

Coffee consumption and gastric cancer: a pooled analysis from the Stomach cancer Pooling Project consortium

OBJECTIVE

This study aimed to evaluate and quantify the relationship between coffee and gastric cancer using a uniquely large dataset from an international consortium of observational studies on gastric cancer, including data from 18 studies, for a total of 8198 cases and 21 419 controls.

METHODS

A two-stage approach was used to obtain the pooled odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) for coffee drinkers versus never or rare drinkers. A one-stage logistic mixed-effects model with a random intercept for each study was used to estimate the dose-response relationship. Estimates were adjusted for sex, age and the main recognized risk factors for gastric cancer.

RESULTS

Compared to never or rare coffee drinkers, the estimated pooled OR for coffee drinkers was 1.03 (95% CI, 0.94-1.13). When the amount of coffee intake was considered, the pooled ORs were 0.91 (95% CI, 0.81-1.03) for drinkers of 1-2 cups per day, 0.95 (95% CI, 0.82-1.10) for 3-4 cups, and 0.95 (95% CI, 0.79-1.15) for five or more cups. An OR of 1.20 (95% CI, 0.91-1.58) was found for heavy coffee drinkers (seven or more cups of caffeinated coffee per day). A positive association emerged for high coffee intake (five or more cups per day) for gastric cardia cancer only.

CONCLUSIONS

These findings better quantify the previously available evidence of the absence of a relevant association between coffee consumption and gastric cancer.

Polymorphism of MUC1 Gene in Vietnamese Gastric Cancer Patients: A Multicenter Case-Control Study

Background

A few studies revealed that the polymorphisms of Mucin 1 gene have a role and significance as a susceptible factor contributing to gastric cancer. To better understand the roles of two MUC1 genotype polymorphisms of rs4072037 and rs2070803 in the development of gastric cancer in Vietnamese population, a multicenter, large-sample, case-control study was conducted to investigate the potential association of these single-nucleotide polymorphisms (SNPs) of MUC1 gene with gastric cancer risk and to evaluate the combination factors in relation with these SNPs.

Methods

This case-control study included 302 gastric cancer patients and 304 controls at four national medical hospitals between 2016 and 2018. All participants were interviewed for sociodemographic characteristics, smoking and drinking status, and personal and family history of gastric diseases. Genotyping was done using polymerase chain reaction-restriction fragment length polymorphism analysis. The association of SNPs with gastric cancer was explored using logistic regression models.

Results

AA genotype for rs4072037 was significantly associated with increased gastric cancer. Those with AA genotype had higher gastric cancer risk than had patients with AG (OR: 2.09, 95% CI: 1.48-2.96) and a combination of AG+GG (OR: 1.85, 95% CI: 1.33-2.56). In rs2070803, GG genotype increased gastric cancer risk when compared with AG (OR: 1.97, 95% CI: 1.39-2.80) and AG+AA (OR: 1.71, 95% CI: 1.23-2.39). AG genotypes in both SNPs decreased gastric cancer risk when compared with homogenous genotype, more specifically AA (OR: 0.51, 95% CI: 0.35-0.72) and GG (OR: 0.58, 95% CI: 0.35-0.97). These genotypes in combination with above-60-year-old age, male gender, alcoholism, and personal history of gastric disease were also significantly elevated risk factors for gastric cancer.

Conclusions

rs4072037 and rs2070803 of Mucin 1 genes are two genotypic risk factors for gastric cancer. Those in combination with gender, family history, smoking, and drinking habits significantly increase the risk of gastric cancer.

Alcohol consumption and risk of stomach cancer: A meta-analysis

Stomach cancer is one of the most common cancers in the world. The relationship between alcohol consumption and the risk of stomach cancer remains unclear. Epidemiology studies investigating this relationship have shown inconsistent findings. A meta-analysis was performed to explore the association between alcohol consumption and increased stomach cancer risk. Eighty-one epidemiology studies, including 68 case-control studies and 13 cohort studies, were included in this study. A significant association was found between alcohol consumption and increased risk of stomach cancer (OR = 1.20, 95% CI 1.12-1.27). To explore the source of the significant heterogeneity (p < 0.05, I² = 86%), analysis was stratified by study type (case-control study and cohort study), control type (hospital-based control and population-based control), gender (male, female, and mix), race (White and Asian), region (United States, Sweden, China, Japan), subsite of stomach cancer, and type of alcohol. The stratified analyses found that region and cancer subsite are major sources of the high heterogeneity. The inconsistent results in different regions and different subsites might be related to smoking rates, Helicobacter pylori infection, obesity, and potential genetic susceptibility. The positive association between drinking and increased risk of stomach cancer is consistent in stratified analyses. The dose-response analysis showed a clear trend that a higher daily intake of alcohol is associated with a higher risk of stomach cancer.

Phytotherapeutic modalities for the management of Helicobacter pylori associated peptic ulcer

Due to an imbalance between aggressive factors known as hydrochloric acid (HCl), pepsin, leukotrienes, refluxed bile, defensive factors and reactive oxygen species, the peptic ulcer is formed in the stomach and duodenum which mostly include the function of prostaglandins, mucus bicarbonate barrier, enzymatic antioxidants, and some growth factors. H. pylori infection remained one of the considerable causes of peptic ulcer as it caused hypochlorhydria and struck off the defense mechanism of the stomach. The nonsteroidal anti-inflammatory drugs (NSAIDs) and stress are the most prevailing causes of peptic ulcer disease. Lack of physical exercise, little rest and due to poor leisure cause the peptic ulcer disease. Candies, chocolate, coffee, cigarettes, stress, and alcohol are the cause of peptic ulceration and suppression of acid in the stomach due to the utilization of antacid medication. Most of the ancient medical practices in the traditional alternative medicinal system include Unani, Ayurveda, Siddha, Homeopathy, Naturopathy, Chinese customary medicine, African conventional medicine, and Native American medicine. Without a hostile effect, the rate of curing the disease is the significance of natural products research. Peptic ulcer disease is the widespread nature of peptic ulcer in all class of population, which mostly may be due to rapidly changing the food habits and stress, causing the imbalance between gastric offensive and defensive factors. Curcuma longa is the most effective plant for the cure of peptic ulcer. Curcuma longa has anti-inflammatory and antioxidant activity. Curcuma longa remarkably reduces the level of inflammatory mediator (IL1) and (TNF) which was increased during the formation of an ulcer. In the rhizome of Curcuma longa, yellow pigment is present and widely used for the treatment of ulcer and decrease the inflammatory response. Symptoms include abdominal pain after taking a meal, nausea, vomiting, Anorexia and lose weight.

Systems-level differential gene expression analysis reveals new genetic variants of oral cancer

Oral cancer (OC) ranked as eleventh malignancy worldwide, with the increasing incidence among young patients. Limited understanding of complications in cancer progression, its development system, and their interactions are major restrictions towards the progress of optimal and effective treatment strategies. The system-level approach has been designed to explore genetic complexity of the disease and to identify novel oral cancer related genes to detect genomic alterations at molecular level, through cDNA differential analysis. We analyzed 21 oral cancer-related cDNA datasets and listed 30 differentially expressed genes (DEGs). Among 30, we found 6 significant DEGs including CYP1A1, CYP1B1, ADCY2, C7, SERPINB5, and ANAPC13 and studied their functional role in OC. Our genomic and interactive analysis showed significant enrichment of xenobiotics metabolism, p53 signaling pathway and microRNA pathways, towards OC progression and development. We used human proteomic data for post-translational modifications to interpret disease mutations and inter-individual genetic variations. The mutational analysis revealed the sequence predicted disordered region of 14%, 12.5%, 10.5% for ADCY2, CYP1B1, and C7 respectively. The MiRNA target prediction showed functional molecular annotation including specific miRNA-targets hsa-miR-4282, hsa-miR-2052, hsa-miR-216a-3p, for CYP1B1, C7, and ADCY2 respectively associated with oral cancer. We constructed the system level network and found important gene signatures. The drug-gene interaction of OC source genes with seven FDA approved OC drugs help to design or identify new drug target or establishing novel biomedical linkages regarding disease pathophysiology. This investigation demonstrates the importance of system genetics for identifying 6 OC genes (CYP1A1, CYP1B1, ADCY2, C7, SERPINB5, and ANAPC13) as potential drugs targets. Our integrative network-based system-level approach would help to find the genetic variants of OC that can accelerate drug discovery outcomes to develop a better understanding regarding treatment strategies for many cancer types.

Olfactory-Related Quality of Life in Multiple Chemical Sensitivity: A Genetic-Acquired Factors Model

Genetic polymorphisms as well as environmental exposures to chemical compounds, iatrogenic, psychological, and physical trauma may play a pathophysiological role in multiple chemical sensitivity (MCS) olfactory complaints, given that xenobiotic metabolism is influenced by sequence variations in genes of metabolizing enzymes. Thus, the aim of the present study was to depict-by means of multiple regression analysis-how different genetic conditions, grouped according to their function as well as clinical background and environmental exposure may interfere with those olfactory complaints referred by MCS patients. Therefore, MCS patients after gene polymorphism sequencing, the olfactory-related quality of life score-calculated by means of the Questionnaire of Olfactory Disorder in forty-six MCS patients-have been found to significantly rely on the phase I and II enzymes score and exposure to previous compounds and surgical treatments. The present work-implementing for the first time a genetic-acquired factors model on a regression analysis-further reinforces those theories, positing MCS as a complex, multifactorial, disease in which the genetic risk related to phase I and II enzymes involved in xenobiotic detoxification, olfactory, and neurodegenerative diseases play a necessary, but probably not sufficient role, along the pathophysiological route of the disease.

Cigarette smoking and gastric cancer in the Stomach Cancer Pooling (StoP) Project

Tobacco smoking is a known cause of gastric cancer, but several aspects of the association remain imprecisely quantified. We examined the relation between cigarette smoking and the risk of gastric cancer using a uniquely large dataset of 23 epidemiological studies within the 'Stomach cancer Pooling (StoP) Project', including 10 290 cases and 26 145 controls. We estimated summary odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) by pooling study-specific ORs using random-effects models. Compared with never smokers, the ORs were 1.20 (95% CI: 1.09-1.32) for ever, 1.12 (95% CI: 0.99-1.27) for former, and 1.25 (95% CI: 1.11-1.40) for current cigarette smokers. Among current smokers, the risk increased with number of cigarettes per day to reach an OR of 1.32 (95% CI: 1.10-1.58) for smokers of more than 20 cigarettes per day. The risk increased with duration of smoking, to reach an OR of 1.33 (95% CI: 1.14-1.54) for more than 40 years of smoking and decreased with increasing time since stopping cigarette smoking (P for trend<0.01) and became similar to that of never smokers 10 years after stopping. Risks were somewhat higher for cardia than noncardia gastric cancer. Risks were similar when considering only studies with information on Helicobacter pylori infection and comparing all cases to H. pylori+ controls only. This study provides the most precise estimate of the detrimental effect of cigarette smoking on the risk of gastric cancer on the basis of individual data, including the relationship with dose and duration, and the decrease in risk following stopping smoking.

The increasing importance of environmental conditions in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative disease affecting motor neurons (MNs). Although a small percentage of ALS has a familial origin, the vast majority of cases are sporadic in which genetic factors and environment interact with each other leading to disease onset in genetically predisposed individuals. In the current model of the disease, each individual has a determined genetic load, some degree of cell degeneration related to age and several risky environmental exposures. In this scenario, MN degeneration would occur when the sum of these factors reach a certain threshold. To date, an extensive list of environmental factors has been associated to ALS, including different categories, such as exposure to heavy metals and other toxicants, cyanotoxins or infectious agents. In addition, in recent years, lifestyle and other demographic parameters are gaining relevance in the genesis of the disease. Among them, physical activity, nutrition, body mass index, cardiovascular risk factors, autoimmune diseases and cancer are some of the conditions which have been related to the disease. In this review, we will discuss the potential mechanisms of environmental conditions in motor neuron degeneration. Understanding the role of each one of these factors as well as their interactions appears as a crucial step in order to develop new preventive, diagnostic and therapeutic approaches for ALS patients.

Adherence to Mediterranean diet and risk of gastric cancer: results of a case-control study in Italy

The aim of this study is to evaluate the association between adherence to Mediterranean diet (MD) and gastric cancer (GC). A case-control study was carried out at the Fondazione Policlinico 'A. Gemelli' (Rome, Italy) from 2003 to 2015. A total of 223 incident cases and 223 controls were interviewed. Dietary intake was assessed through a validated food frequency questionnaire that collected information on more than 25 food items. The association between adherence to MD and risk of GC was quantified by calculating Odds Ratios (OR) and 95% confidence intervals (CI). The analysis reports that a higher adherence to MD is associated with a reduced risk of GC (OR: 0.70; 95% CI: 0.61-0.81). A high consumption of vegetables (OR: 0.34; 95% CI: 0.14-0.85), legumes (OR: 0.13; 95% CI: 0.06-0.29), and fish (OR: 0.33; 95% CI: 0.15-0.68), as well as low consumption of meat (OR: 0.29; 95% CI: 0.10-0.85) and alcohol (OR: 0.46; 95% CI: 0.24-0.90) are consistently related to a lower risk of GC. Our study indicates a protective role of the MD eating pattern and MD individual components against GC. Our results showed a beneficial role of high vegetable, legume, and fish consumption, along with low intake of alcohol and meat in the development of GC.

Glutathione S-transferase M1 and T1 null genotype frequency distribution among four tribal populations of western India

Glutathione S transferase (GST) family is a key contributor in the detoxification mechanism of our body.Deletion of the genes within this family has been reported in the failure of detoxification system, to some extent leading to various types of cancers and other life threatening diseases. The existing data and reports on the association of null genotype of both GSTM1 and GSTT1 genes for various diseases are inconsistent. But knowledge of the polymorphic distributions of genotypes in different populations is important for investigating the risk factors in different epidemiological studies. The present study thus aims to determine thefrequency of GSTM1 and GSTT1 null genotype frequency among four tribal groups, i.e. Mina, Garasia, Damor and Saharia of western India. A comparative analysis with different tribal as well as world population has also been undertaken to have a view of its worldwide frequency distribution. Our results reveal a frequency distribution varying from 22.6% to 66.9% with respect to GSTM1gene polymorphism and from 19.1% to 33.0% with respect to GSTT1 gene in the studied populations. To the best of our knowledge this is the first report on the GSTM1and GSTT1frequency distribution among the tribal population of western India and our study shows that the Mina tribal population has the highest frequency of GSTM1.

Associations of Functional MicroRNA Binding Site Polymorphisms in IL23/Th17 Inflammatory Pathway Genes with Gastric Cancer Risk. Mediators Inflamm. 2017;2017:6974696. [PMID: 29118466 PMCID: PMC5651119 DOI: 10.1155/2017/6974696]

IL23/Th17 axis acts as an inflammatory pathway in gastric carcinogenesis. MicroRNA- (miRNA-) binding site single-nucleotide polymorphisms (SNPs) of inflammatory genes may alter gastric cancer (GC) susceptibility. In this study, four miRNA binding site SNPs (rs3748067 of IL17A, rs887796, rs1468488 of IL17RA, and rs10889677 of IL23R) were genotyped from 500 patients and 500 controls. Unconditional logistic regression analyses and multifactor dimensionality reduction software were used to evaluate the relationships of SNPs with GC and gene-environment interactions, respectively. Quantitative real-time PCR, Western blot analysis, and luciferase report gene assay were applied for function verification. We found that CT (OR_adj = 0.59; 95% CI: 0.44-0.79), CT + TT (OR_adj = 0.58; 95% CI: 0.43-0.77) genotypes, and T allele (OR_adj = 0.77; 95% CI: 0.47-0.80) of rs3748067 reduced GC risk; the rs10889677 CC genotype (OR_adj = 2.22; 95% CI: 1.27-3.87) and C allele (OR_adj = 1.24; 95% CI: 1.02-1.52) increased GC risk. A meaningful interaction among ever smoked, family history of GC, and rs3748068 could intensify GC risk by 2.25-fold. Functional tests demonstrated the inhibitory effect of miR-10a-3p on IL17A expression in SGC-7901 cells. These results suggested that miRNA binding site SNPs within IL23/Th17 inflammatory pathway genes and their interactions with environmental factors could be associated with GC risk.

GENOTYPE ASSOCIATION GSTM1 NULL AND GASTRIC CANCER: EVIDENCE-BASED META-ANALYSIS

BACKGROUND

Gastric cancer is the fourth most common cancer in men and the sixth among women, except for non-melanoma skin tumors, in Brazil. Epidemiological evidences reveal the multifactorial etiology of this cancer, highlighting risk factors such as: infection by the bacterium Helicobacter pylori, advanced age, smoking, chronic alcohol abuse, eating habits and genetic polymorphisms. Considering the context of genetic polymorphisms, there is the absence of the GSTM1 gene. The lack of GSTM1 function to detoxify xenobiotics and promote defense against oxidative stress leads to increased DNA damage, promoting gastric carcinogenesis. This process is multifactorial and the development of gastric cancer results from a complex interaction of these variables.

OBJECTIVE

The aim of this study was to investigate the association of GSTM1 null polymorphism in the pathogenesis of gastric cancer.

METHODS

A meta-analysis was conducted from 70 articles collected in SciELO and PubMed databases, between September 2015 and July 2016. In order to evaluate a possible association, we used the odds ratio (OR) and confidence interval of 95% (CI 95%). To assess the heterogeneity of the studies was used the chi-square test. Statistical analysis was performed using the BioEstat® 5.3.

RESULTS

This study included 70 studies of case-control, including 28,549 individuals, which were assessed for the null polymorphism of the GSTM1 gene, and of which 11,208 (39.26%) were cases and 17,341 (60.74%) were controls. The final analysis showed that the presence of the GSTM1 gene acts as a protective factor against the development of gastric cancer (OR=0.788; 95%CI 0.725-0.857; P<0.0001). Positive statistical association was found in Asia (OR=0.736; 95%CI 0.670-0.809; P<0.0001) and Eurasia (OR=0.671; 95%CI 0.456-0.988; P=0.05). However, statistically significant data was not obtained in Europe (OR=1.033; 95%CI 0.873-1.222; P=0.705) and America (OR=0.866; 95%CI 0.549-1.364; P=0.534). Therefore, the results can not be deduced around the world.

CONCLUSION

This meta-analysis concluded that the presence of the GSTM1 gene is a protector for the emergence of gastric cancer, especially in Asian countries, but this result was not found in Europe and America.

Xenobiotic Pathway Gene Polymorphisms Associated with Gastric Cancer in High Risk Mizo-Mongoloid Population, Northeast India

BACKGROUND

The aim of this study was to evaluate the risk of gastric cancer associated with individual or combined glutathione S-transferases (GSTs) polymorphism and their interaction with environmental factors.

MATERIALS AND METHODS

Genotyping by PCR was carried out for 80 cases and controls each for GSTM1, GSTT1, and GSTP1 polymorphism and mapped for gene-environment association studies. The samples were subjected to pathogen detection and GSTP1 expression for analyzing their association with different genotypes. Logistic regression analyses were conducted to compute the influence of both genetic and environmental factors for gastric cancer. MDR analysis was performed to assess the risk of gastric cancer by studying the gene-gene and gene-environment effect on the basis of GST genotyping and GSTP1 gene expression.

RESULTS

Infection with Helicobacter pylori and CagA+ strains was more frequent in patients with GSTM1/T1 null genotype. Intake of high fermented fat and smoked meat was found to be significantly associated with gastric cancer. The G/G, A/G (rs1695), and T/T (rs1138272) were found to be significantly associated with low expression of GSTP1 gene in cancer tissue.

CONCLUSION

Presence of H. pylori with CagA genotype showed significant individual effect with GSTT1 polymorphism as well as strong synergistic effect in gastric cancer risk. Majority of the gastric cancer samples showed significant negative expression in G/G, A/G (rs1695), and T/T (rs1138272) genotypes. This study shows that GST gene polymorphism was significantly relevant for determining the individual susceptibility to gastric cancer.

CYP1A1, GSTM1 and GSTT1 genetic polymorphisms and gastric cancer risk among Japanese: A nested case-control study within a large-scale population-based prospective study

Cytochrome P450 (CYP) 1A1 and glutathione S-transferases (GST) M1 and T1 are major enzymes in the carcinogen metabolizing pathway. We examined the association between single nucleotide polymorphisms (SNPs) of CYP1A1 (rs4646421, rs4646422 and rs1048943), GSTM1 and GSTT1 and gastric cancer risk in Japan. This is a nested case-control study (457 cases and 457 matched controls) of our population-based cohort involving 36,745 subjects who answered a baseline questionnaire and supplied blood samples. The odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated using conditional logistic regression models. We found that CYP1A1 (rs4646422) variant allele was associated with a statistically significant increased risk of gastric cancer compared with the homozygous wild-type genotype (OR = 1.65; 95% CI = 1.17-2.32). GSTM1 null, GSTT1 null and GSTM1/T1 both or either null genotypes were associated with increased risk, but not statistically significantly. Combination of the CYP1A1 (rs4646422) variant allele and GSTM1/T1 both or either null genotypes was associated with a statistically significant increased risk compared with the combination of the CYP1A1 homozygous wild-type genotype and the GSTM1/T1 both active genotypes. In addition, compared with CYP1A1 (rs4646422) homozygous wild-type genotypes in those who were never-smokers, CYP1A1 variant alleles in those who smoked ≥30 pack-years were associated with an increased risk; neither gene-gene nor gene-environment interactions were significant. The CYP1A1 (rs4646422) polymorphism might be involved in gastric carcinogenesis among the Japanese population.

POLYMORPHISMS OF DRUG-METABOLIZING ENZYMES CYP1A2, CYP2D6, GST, NAT2 AND TRANSPORTER MDR1 IN POPULATION OF BELARUS: COMPARISON WITH SELECTED EUROPEAN AND ASIAN POPULATIONS

Drug therapeutic efficiency and development of unfavorable pharmacologic responses as well as the disease predisposition are caused first of all by patient’s genetic features. Genetic variations in genes encoding drug-metabolizing enzymes and transporter proteins are essential to understand the ethnic differences in disease occurrence, development, prognosis, therapeutic response and toxicity of drugs. For that reason, it is necessary to establish the normative frequency distribution of genotypes and alleles of these genes in a particular population. Data on frequency of pharmacogenetic polymorphisms in the of Belarus population are limited. The goal of our investigation was to analyze the frequency distribution of genotypes and alleles of genes encoding drug-metabolizing enzymes (CYP1А2, CYP2D6 – I phase; GSTs, NAT2 – II phase) and transporter protein MDR1 in the population of Belarus and comparisons with other ethnic populations. Our results indicate that clinically important genes are genetically highly variable and differ considerably between populations. Differences in allele frequencies across continents should be considered when designing clinical trials of new drugs continents should be considered when designing clinical trials of new drugs.

Molecular alterations in gastric cancer with special reference to the early-onset subtype

Currently, gastric cancer (GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the pro-carcinogenic activity of important genes. These factors include genetic susceptibility expressed in a single-nucleotide polymorphism, various acquired mutations (chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances (e.g., Helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma (EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesis are modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

Pharmacogenetics of drug-metabolizing enzymes in Italian populations

Drug-metabolizing enzymes play a major role in the biotransformation and subsequent elimination of most drugs and xenobiotics from the body. Both phase I and phase II enzymes are highly polymorphic. Inter-individual differences in genes coding for drug-metabolizing enzymes are important for understanding variability in drug response and for individualization of drug prescription. The prevalence of genetic polymorphisms in drug metabolism varies widely with ethnicity, and marked differences in the distribution of allelic variants of genes encoding drug-metabolizing enzymes have been documented in populations of different racial origin. This review aimed to summarize the available studies on genetic polymorphisms associated with drug metabolism conducted in Italian populations and to compare the frequency of the various metabolizer phenotypes and most common variant alleles (and resulting genotypes) with corresponding values from other populations. Notably, published data are not extensive, and most studies were performed on relatively low numbers of individuals. In general, the frequency of polymorphisms in the cytochrome P450 (CYP) genes as well as in the investigated phase II enzymes in the Italian population was similar to values reported for other Caucasian populations. However, the prevalence of CYP2D6 gene duplication among Italians was found to be very high, confirming the higher frequency of CYP2D6 ultrarapid metabolizers in the Mediterranean area compared to Northern Europe. It is worth noting that a geographic gradient in the flavin-containing monooxygenase 3 polymorphism distribution was also seen, the Italian population showing higher similarity to other Mediterranean populations than to North Europeans.

Glutathione S-transferase gene GSTM1, gene-gene interaction, and gastric cancer susceptibility: evidence from an updated meta-analysis

Background

The null genotype of GSTM1 have been implicated in gastric cancer risk, but numerous individual studies showed mixed, or even conflicting results. Thus, a meta-analysis was performed.

Results

We identified 54 individual studies involving 9,322 cases and 15,118 controls through computer-based searches of PubMed, Embase, and Cochrane Library. It was found that the null genotype of GSTM1 was associated with an increased gastric cancer risk (OR = 1.207, 95% CI: 1.106-1.317, P < 0.001), under the random-effects model (I² : 49.9%, P_Q <0.001). From stratification analyses for ethnicity, alcohol drinking, Helicobacter pylori infection, an effect modification of gastric cancer risk was found in the subgroups of ethnicity, smoking status, Helicobacter pylori infection, whereas null result was found in the subgroups of alcohol drinking. We also undertook gene-gene interaction analysis between GSTM1 and GSTT1 genes for gastric cancer risk, and the results indicated that the dual null genotypes of GSTM1 and GSTT1 might elevate the risk of gastric cancer (OR = 1.505, 95% CI: 1.165-1.944, P = 002).

Conclusions

This meta-analysis suggests that the null genotype of GSTM1 may be a important genetic risk factor for gastric cancer development.

Sulfotransferase SULT1A1 Arg213His polymorphism with cancer risk: a meta-analysis of 53 case-control studies

Background

The SULT1A1 Arg213His (rs9282861) polymorphism is reported to be associated with many kinds of cancer risk. However, the findings are conflicting. For better understanding this SNP site and cancer risk, we summarized available data and performed this meta-analysis.

Methods

Data were collected from the following electronic databases: PubMed, Web of Knowledge and CNKI. The association was assessed by odd ratio (OR) and the corresponding 95% confidence interval (95% CI).

Results

A total of 53 studies including 16733 cancer patients and 23334 controls based on the search criteria were analyzed. Overall, we found SULT1A1 Arg213His polymorphism can increase cancer risk under heterozygous (OR = 1.09, 95% CI = 1.01–1.18, P = 0.040), dominant (OR = 1.10, 95% CI = 1.01–1.19, P = 0.021) and allelic (OR = 1.08, 95% CI = 1.02–1.16, P = 0.015) models. In subgroup analyses, significant associations were observed in upper aero digestive tract (UADT) cancer (heterozygous model: OR = 1.62, 95% CI = 1.11–2.35, P = 0.012; dominant model: OR = 1.63, 95% CI = 1.13–2.35, P = 0.009; allelic model: OR = 1.52, 95% CI = 1.10–2.11, P = 0.012) and Indians (recessive model: OR = 1.93, 95% CI = 1.22–3.07, P = 0.005) subgroups. Hospital based study also showed marginally significant association. In the breast cancer subgroup, ethnicity and publication year revealed by meta-regression analysis and one study found by sensitivity analysis were the main sources of heterogeneity. The association between SULT1A1 Arg213His and breast cancer risk was not significant. No publication bias was detected.

Conclusions

The present meta-analysis suggests that SULT1A1 Arg213His polymorphism plays an important role in carcinogenesis, which may be a genetic factor affecting individual susceptibility to UADT cancer. SULT1A1 Arg213His didn't show any association with breast cancer, but the possible risk in Asian population needs further investigation.

Gene-diet interactions in gastric cancer risk: A systematic review

AIM: To conduct a systematic review of the published epidemiological studies investigating the association of the interactions between gene variants and dietary intake with gastric cancer risk.

METHODS: A literature search was conducted in PubMed, EMBASE, and MEDLINE for articles published between January 2000 and July 2013, and 38 studies were identified. Previous studies included various dietary factors (e.g., fruits and vegetables, soybean products, salt, meat, and alcohol) and genetic variants that are involved in various metabolic pathways.

RESULTS: Studies suggest that individuals who carry high-risk genetic variants and demonstrate particular dietary habits may have an increased risk of gastric cancer compared with those who do not carry high-risk genetic variants. Distinctive dietary patterns and variations in the frequency of genetic variants may explain the higher incidence of gastric cancer in a particular region. However, most previous studies have limitations, such as a small sample size and a retrospective case-control design. In addition, past studies have been unable to elucidate the specific mechanism in gene-diet interaction associated with gastric carcinogenesis.

CONCLUSION: Additional large prospective epidemiological and experimental studies are required to identify the gene-diet metabolic pathways related to gastric cancer susceptibility.

N-acetyltransferase 2 status and gastric cancer risk: a meta-analysis

Case-control studies on the association between N-acetyltransferase 2 (NAT2) genotype and gastric cancer have provided either controversial or inconclusive results. In order to clarify the influence of NAT2 acetylation status on gastric cancer risk, a meta-analysis was undertaken. The primary outcome measure was the odds ratio (OR) for the risk of gastric cancer associated with the NAT2 genotype. The overall result showed that there was no statistically significant association between NAT2 status and gastric cancer risk (slow acetylation vs. rapid acetylation, OR = 1.10, 95 % confidence interval (CI) 0.97-1.25, p = 0.12). In the analysis stratified by East Asian ethnicity, a significant association was found between gastric cancer and the NAT2 genotype (slow acetylation vs. rapid acetylation, OR = 1.33, 95 % CI 1.11-1.59, p = 0.002). Our pooled data suggest that the NAT2 acetylation status has an effect on the risk of gastric cancer among East Asian populations.

Glutathione S-transferase M1 null genotype meta-analysis on gastric cancer risk

Background

Glutathione S-transferases (GSTs) have proved to be involved in the detoxifying several carcinogens and may play an important role in carcinogenesis of cancer. Previous studies on the association between Glutathione S-transferase M1 (GSTM1) polymorphism and gastric cancer (GC) risk reported inconclusive results. To get a precise result, we conducted this present meta-analysis through pooling all eligible studies.

Methods

A comprehensive databases of Pubmed, Embase, Web of Science, and the Chinese Biomedical Database (CBM) were searched for case–control studies investigating the association between GSTM1 null genotype and GC risk. Odds ratios (OR) and 95% confidence intervals (95% CI) were used to assess this possible association. A χ2-based Q-test was used to examine the heterogeneity assumption. Begg’s and Egger’s test were used to examine the potential publication bias. The leave-one-out sensitivity analysis was conducted to determine whether our assumptions or decisions have a major effect on the results of present work. Statistical analyses were performed with the software program STATA 12.0.

Results

A total of 47 eligible case–control studies were identified, including 6,678 cases and 12,912 controls. Our analyses suggested that GSTM1 null genotype was significantly associated with increased risk of GC (OR = 1.186, 95% CI = 1.057-1.329, P_{heterogenetiy} = 0.000, P = 0.004). Significant association was also found in Asians (OR = 1.269, 95% CI = 1.106-1.455, P_{heterogenetiy} = 0.002, P = 0.001). However, GSTM1 null genotype was not contributed to GC risk in Caucasians (OR = 1.115, 95% CI = 0.937-1.326, P_{heterogenetiy} = 0.000, P = 0.222). In the subgroup analysis stratified by sources of controls, significant association was detected in hospital-based studies (OR = 1.355, 95% CI = 1.179-1.557, P_{heterogenetiy} = 0.001, P = 0.000), while there was no significant association detected in population-based studies (OR = 1.017, 95% CI = 0.862-1.200, P_{heterogenetiy} = 0.000, P = 0.840).

Conclusion

This meta-analysis showed the evidence that GSTM1 null genotype contributed to the development of GC.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1644180505119533.

Association between copy number variation losses and alcohol dependence across African American and European American ethnic groups

BACKGROUND

Copy number variations (CNVs) are structural genetic mutations consisting of segmental gains or losses in DNA sequence. Although CNVs contribute substantially to genomic variation, few genetic and imaging studies report association of CNVs with alcohol dependence (AD). Our purpose is to find evidence of this association across ethnic populations and genders. This work is the first AD-CNV study across ethnic groups and the first to include the African American (AA) population.

METHODS

This study considers 2 CNV data sets, one for discovery (2,345 samples) and the other for validation (239 samples), both including subjects with AD and healthy controls of European and African ancestry. Our analysis assesses the association between AD and CNV losses across ethnic groups and gender by examining the effect of overall losses across the whole genome, collective losses within individual cytogenetic bands, and specific losses in CNV regions.

RESULTS

Results from the discovery data set showed an association between CNV losses within 16q12.2 and AD diagnosis (p = 4.53 × 10(-3) ). An overlapping CNV region from the validation data set exhibited the same direction of effect with respect to AD (p = 0.051). This CNV region affects the genes CES1p1 and CES1, which are members of the carboxylesterase (CES) family. The enzyme encoded by CES1 is a major liver enzyme that typically catalyzes the decomposition of ester into alcohol and carboxylic acid and is involved in drug or xenobiotics, fatty acid, and cholesterol metabolisms. In addition, the most significantly associated CNV region was located at 9p21.2 (p = 1.9 × 10(-3) ) in our discovery data set. Although not observed in the validation data set, probably due to small sample size, this result might hold potential connection to AD given its connection with neuronal death. In contrast, we did not find any association between AD and the overall total losses or the collective losses within individual cytogenetic bands.

CONCLUSIONS

Overall, our study provides evidence that the specific CNVs at 16q12.2 contribute to the development of alcoholism in AA and European American populations.

Cytochrome P450 1A1, 2E1 and GSTM1 gene polymorphisms and susceptibility to colorectal cancer in the Saudi population

BACKGROUND

The Saudi population has experienced a sharp increase in colorectal and gastric cancer incidences within the last few years. The relationship between gene polymorphisms of xenobiotic metabolizing enzymes and colorectal cancer (CRC) incidence has not previously investigated among the Saudi population. The aim of the present study was to investigate contributions of CYP1A1, CYP2E1, and GSTM1 gene polymorphisms.

MATERIALS AND METHODS

Blood samples were collected from CRC patients and healthy controls and genotypes were determined by polymerase chain reaction restriction fragment length polymorphism and sequencing.

RESULTS AND CONCLUSIONS

CYP2E1*6 was not significantly associated with CRC development (odd ratio=1.29; confidence interval 0.68-2.45). A remarkable and statistically significant association was observed among patients with CYP1Awt/*2A (odd ratio=3.65; 95% confidence interval 1.39-9.57). The GSTM1*0/*0 genotype was found in 2% of CRC patients under investigation. The levels of CYP1A1, CYP2E1 and GSTM1 mRNA gene expression were found to be 4, 4.2 and 4.8 fold, respectively, by quantitative real time PCR. The results of the present case-control study show that the studied Saudi population resembles Caucasians with respect to the considered polymorphisms. Investigation of genetic risk factors and susceptibility gene polymorphisms in our Saudi population should be helpful for better understanding of CRC etiology.

Susceptibility to Helicobacter pylori infection: results of an epidemiological investigation among gastric cancer patients

The aim of this study was to identify the clinical, demographic, lifestyle factors and selected genetic polymorphisms that affect the susceptibility towards Helicobacter pylori (H. pylori) infection in gastric cancer patients. Histological confirmed gastric adenocarcinoma cases that underwent curative gastrectomy between 2002 and 2012 were included. Gastric biopsy samples were obtained to determine the H. pylori status, and further cagA status and vacA m and s genotypes by polymerase chain reaction. Patients were interviewed with structured questionnaires, and blood samples were collected for EPHX1, GSTM1, GSTT1, IL1B, IL1-RN, MTHFR and p53 genotyping. Proportions were compared in univariate analysis, while the relation between putative risk factors and H. pylori status and genotype were measured using logistic regression analysis. One hundred forty-nine gastric cancer patients were included, of which 78.5% were H. pylori positive. Among positive patients 50% were cagA+, 72.5% vacA m1 and 80.7% vacA s1. The presence of cagA was less frequent among vacA m1 (p = 0.031) and vacA s1 (p = 0.052) subtypes. The presence of father history for any cancer was a significant risk factor for H. pylori infection [adjusted odds ratio (OR) = 8.18, 95% confidence interval (CI) 1.04-64.55]. EPHX1 exon 3 T > C (OR = 0.35, CI 95% 0.13-0.94), IL1B-511 T > C (OR = 0.38, CI 95% 0.15-0.97) and IL1-RN VNTR (OR = 0.19, CI 95% 0.06-0.58) polymorphisms were protective towards H. pylori infection in the univariate analysis. Wine consumption was associated with higher risk of carrying the H. pylori vacA m1 virulent subtype (p = 0.034). Lastly, cardiovascular diseases were less common among cagA positive subjects (p = 0.023). Father history of any cancer is a risk factor for H. pylori infection. Polymorphisms in IL1B-511, IL1-RN and EPHX1 exon 3 genes might be protective towards H. pylori infection.

The effect of CYP1A1 and CYP1A2 polymorphisms on gastric cancer risk among different ethnicities: a systematic review and meta-analysis

Potential Cytochrome P450s (CYPs) 1A1 MspI, 1A1 Ile462Val, 1A2*1 F, and/or 1A2*1C polymorphisms have been implicated in gastric cancer risk among different ethnicities. We aimed to explore the effect of CYP 1A1 MspI, 1A1 Ile462Val, 1A2*1 F, and/or 1A2*1C polymorphisms on the susceptibility to gastric cancer among different ethnicities through a systematic review and meta-analysis. Each initially included article was scored for quality appraisal. Desirable data were extracted and registered into databases. A number of 11 studies were ultimately eligible for the meta-analysis of CYP1A1 MspI polymorphism, eight studies for the meta-analysis of 1A1 Ile462Val polymorphism, and two studies for the meta-analysis of 1A2*1 F polymorphism. None of genetic model was evidently suggested, and thus all the genetic models were presented. Potential sources of heterogeneity were sought out via subgroup and sensitivity analyses, and publication biases were estimated. In our meta-analysis, significant results could be found in mutational heterozygous CT genotype, compared with wild TT genotype, among large sample size subgroup for CYP1A1 MspI polymorphism. Regarding CYP1A1 Ile462Val polymorphism, no statistically significant results could be found. For CYP1A2*1 F polymorphism, mutational heterozygous AC genotype, compared with wild-type AA, has deleterious effects, whereas mutational homozygous CC genotype, compared with mutational heterozygous type AC, has protective effects but lacks statistically significant difference despite its a proximity to 0.05. Combined mutational homozygous CC genotype and wild-type homozygous AA, compared with mutational heterozygous AC genotype, has protective effects. Our meta-analysis suggests no associations between CYP1A1 Ile462Val polymorphism and gastric cancer, but possible associations between CYP1A1 MspI and CYP1A2*1 F polymorphisms and gastric cancer, which needs to be further reinforced or refuted among different ethnicities in well-designed large-scale high-quality studies.

Meta-analysis of the association of glutathione S-transferase T1 null/presence gene polymorphism with the risk of gastric carcinoma

A possible association of glutathione S-transferase T1 (GSTT1) null/presence gene polymorphism and an increased risk of developing gastric carcinoma is still unclear and hotly debated. This investigation was performed to assess the association of the GSTT1 null/presence gene polymorphism with the risk of gastric carcinoma via a meta-analysis to increase sample size and statistical significance. PubMed, Cochrane Library and CBM-disc (China Biological Medicine Database) were searched on March 1, 2013, association reports were identified, and eligible studies were recruited and synthesized. Fifty-two reports were found to be suitable for this meta-analysis for the association of the GSTT1 null genotype with gastric carcinoma risk. The results showed that there was a significantly increased gastric carcinoma risk when the GSTT1 null genotype was present in the overall population (OR 1.21, 95 % CI 1.11-1.32, P < 0.0001), Caucasians (OR 1.25, 95 % CI 1.05-1.48, P = 0.01), East-Asians (OR 1.18, 95 % CI 1.06-1.31, P = 0.003), and Chinese (OR 1.24, 95 % CI 1.07-1.44, P = 0.005). However, no statistically relevant association could be established for the Indian ethnic group (OR 1.33, 95 % CI 0.94-1.90, P = 0.11). In conclusion, the GSTT1 null genotype is associated with an increased gastric carcinoma risk in the overall population, Caucasians, East-Asians, and Chinese.

GSTM1 null genotype is associated with increased risk of gastric cancer in both ever-smokers and non-smokers: a meta-analysis of case-control studies

Previous studies have suggested that the glutathione S-transferases M1 (GSTM1) null genotype is associated with the risk of gastric cancer. However, the interaction between GSTM1 null genotype and smoking for the risk of gastric cancer is still elusive. Therefore, we performed a meta-analysis to ascertain this issue. Databases of PubMed, EMBASE, and China National Knowledge Infrastructure were searched to retrieve relevant studies. Smokers were categorized as "ever-smokers" and "non-smokers." Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to estimate the association strength. Subgroup analyses according to ethnicity, source of control, and sample size were also conducted. A total of 15 eligible studies, including 4,687 gastric cancer cases and 7,002 controls, were identified. We found that the GSTM1 null genotype was associated with increased risk of gastric cancer among ever-smokers (OR = 1.460, 95% CI 1.064-2.003, heterogeneity: P = 0.019). The null genotype also significantly increased the risk of gastric cancer among non-smokers (OR = 1.777, 95% CI 1.301-2.426, heterogeneity: P < 0.01). Stratified analysis according to ethnicity showed that the GSTM1 null genotype was associated with increased risk of gastric cancer among Asians both in ever-smokers (OR = 1.841, 95% CI 1.184-2.861) and non-smokers (OR = 1.773, 95% CI 1.382-2.275). In conclusion, the GSMT1 null genotype significantly increased the risk of gastric cancer both in ever-smokers and non-smokers.

The GSTM1 null genotype increased risk of gastric cancer: a meta-analysis based on 46 studies

Background

Glutathione S-transferases M1 (GSTM1) is an important phase II metabolizing enzyme. The null genotype of GSTM1 causes total loss of GSTM1 enzyme activity and numerous studies have investigated the association between GSTM1 null genotype and gastric cancer risk.

Methods

This meta-analysis was designed to investigate the relationship between GSTM1 null genotype and susceptibility to gastric cancer and assess the influence of Helicobacter pylori infection, smoking, Lauren’s classification, and other factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate the association strength.

Results

A total of 46 eligible studies were indentified and analyzed in this meta-analysis, including 8138 cases of gastric cancer and 13867 controls. Pooled results showed that the GSTM1 null genotype was associated with a significantly increased risk of gastric cancer (OR=1.217, 95% CI: 1.113-1.331, P_{heterogeneity}<0.001). Sub-group analysis suggested that the significant association was only observed in Asians (OR=1.273, 95%: 1.137-1.426, P_{heterogeneity} = 0.002), but not in Caucasians. The increased risk was found among H. pylori positive population (OR=1.928, 95% CI: 1.028-3.615, P_{heterogeneity}=0.065), while no association was found among H. pylori negative population (OR=0.969, 95% CI: 0.618-1.521, P_{heterogeneity}=0.168). For smoking status, the GSTM1 null genotype increased risk of gastric cancer in both ever-smokers and non-smokers. Source of control, sample size, location of tumor and Lauren’s classification did not modify the association.

Conclusions

In this meta-analysis based on 46 epidemiological studies, we show that the GSTM1 null genotype is associated with an increased risk of gastric cancer among Asians but not among Caucasians. H. pylori infection but not smoking status could modify the association.

Meta-analysis: glutathione S-transferase T1 null allele is associated with gastric cancer risk

Allelic variant within genes encoding glutathione S-transferase T1 (GSTT1) has been suggested to be a possible risk factor of gastric cancer, but previous studies provide controversial results. This study aimed to assess the effects of GSTT1 polymorphism on gastric cancer by means of meta-analysis. We included published studies on the relationship between GSTT1 null allele and gastric cancer risk after searching electronic databases. A meta-analysis was conducted by calculating the pooled odds ratios (OR) and the 95% confidence intervals (95% CI). Forty-two studies with a total of 8,203 gastric cancer cases and 13,866 controls were included into this meta-analysis. When all 42 studies were pooled into this meta-analysis, there was a significant association between the GSTT1 null allele and gastric cancer risk (OR = 1.24, 95% CI 1.14-1.36, P < 0.00001). Sensitivity analysis by excluding individual studies showed that there was no effect on the pooled OR with 95% CI. After excluding studies with low quality, there was still a significant association between the GSTT1 null allele and gastric cancer risk (OR = 1.24, 95% CI 1.13-1.36, P < 0.00001). In the subgroup analysis, there was a significant association between the GSTT1 null allele and gastric cancer risk in both Europeans and Asians. There was no risk of publication bias in this meta-analysis. Our results suggest that GSTT1 null allele is associated with increased risk of gastric cancer.

Quantitative assessment of the influence of glutathione S-transferase T1 null variant on gastric cancer risk

Glutathione S-transferase T1 (GSTT1) catalyzes reactions between glutathione and lipophilic compounds with electrophilic centers, leading to neutralization of toxic compounds, xenobiotics, and products of oxidative stress. In the past decade, a number of case-control studies have been carried out to investigate the relationship between the GSTT1 null polymorphism and gastric cancer (GC), but the results have been inconclusive. To investigate this inconsistency, we performed a meta-analysis of 46 studies involving a total of 9012 GC cases and 14,215 controls for null variant of the GSTT1 gene to evaluate the effect of GSTT1 on genetic susceptibility for GC. Potential sources of heterogeneity including ethnicity, source of control, and sample size were also assessed. Overall, significantly increased GC risk was associated with GSTT1 null polymorphism with OR of 1.20 (95% CI, 1.10-1.32; P < 0.05). In the subgroup analysis by ethnicity, significantly increased risks were found in East Asians and Indians, while no significant associations were found among Caucasian, and Middle Eastern and African populations. By pooling data from 19 studies that considered combinations of GSTT1 and GSTM1 genotypes, a statistically significant increased risk for GC (OR = 2.04, 95% CI, 1.49-2.64; P < 0.05) was detected for individuals with dual deletion in both genes compared with positive genotypes. In addition, we found that cigarette smoking and alcohol drinking may modified the association of GSTT1 null genotypes with the risk of GC. In conclusion, this meta-analysis suggests that GSTT1 null polymorphism is associated with elevated GC risk, but these associations vary in different ethnic populations.

Exposure to environmental toxicants and pathogenesis of amyotrophic lateral sclerosis: state of the art and research perspectives

There is a broad scientific consensus that amyotrophic lateral sclerosis (ALS), a fatal neuromuscular disease, is caused by gene--environment interactions. In fact, given that only about 10% of all ALS diagnosis has a genetic basis, gene-environmental interaction may give account for the remaining percentage of cases. However, relatively little attention has been paid to environmental and lifestyle factors that may trigger the cascade of motor neuron degeneration leading to ALS, although exposure to chemicals--including lead and pesticides-agricultural environments, smoking, intense physical activity, trauma and electromagnetic fields have been associated with an increased risk of ALS. This review provides an overview of our current knowledge of potential toxic etiologies of ALS with emphasis on the role of cyanobacteria, heavy metals and pesticides as potential risk factors for developing ALS. We will summarize the most recent evidence from epidemiological studies and experimental findings from animal and cellular models, revealing that potential causal links between environmental toxicants and ALS pathogenesis have not been fully ascertained, thus justifying the need for further research.

A survey and evaluation of population-based screening for gastric cancer

Screening and early diagnosis of gastric cancer play important roles in reducing the mortality of gastric cancer. A vast amount of study data on gastric cancer screening and early diagnosis has been accumulated in and out of China in the past decades. The practice of gastric cancer screening has also been efficiently carried out in different countries and regions. However, no widely accepted principle of population screening for gastric cancer has been developed yet. Screening for gastric cancer requires extensive exploration both theoretically and practically. This article focuses on the method and program of gastric cancer screening based on population. Moreover, the current situation of gastric cancer screening and its evaluation are evaluated.

Glulathione-S-transferases gene polymorphism in prediction of gastric cancer risk by smoking and Helicobacter pylori infection status

AIM

To evaluate the association of glutathione S-transferases gene polymorphisms with the risk of gastric cancer, with reference to smoking and Helicobacter pylori infection.

METHODS

We conducted a 1:1 matched case-control study with 410 gastric cancer cases and 410 cancer-free controls. Polymorphisms of GSTM1, GSTT1 and GSTP1 were determined using PCR-CTPP.

RESULTS

The GSTM1 and GSTT1 null genotypes were significantly associated with the risk of gastric cancer after adjusting for potential confounding factors (OR=1.68, 95% CI=1.32-2.23 for null GSTM1, OR=1.73; 95% CI=1.24-2.13 for null GSTT1). The combination of null GSTM1 and null GSTT1 conferred an elevated risk (OR=2.54, 95% CI=1.55-3.39). However, no association was found for GSTP1 polymorphism The smoking modified the association of GSTM1 and GSTT1 null genotypes with the risk of gastric cancer.

CONCLUSION

GSTM1 and GSTT1 null genotypes are associated with increased risk of gastric cancer, and smoking modifies the association.

Association between glutathione S-transferase T1 null genotype and gastric cancer risk: a meta-analysis of 48 studies

BACKGROUND

Glutathione S-transferases (GSTs) have proved to be involved in the detoxifying several carcinogens and may play an important role in carcinogenesis of cancer. Previous studies on the association between Glutathione S-transferase T1 (GSTT1) polymorphism and gastric cancer risk reported inconclusive results. To clarify the possible association, we conducted a meta-analysis of eligible studies.

METHODS

We searched in the Pubmed, Embase, and Wangfang Medicine databases for studies assessing the association between GSTT1 null genotype and gastric cancer risk. The pooled odds ratio (OR) and its 95% confidence interval (95%CI) was calculated to assess the strength of the association. A total of 48 studies with a total of 24,440 individuals were ultimately eligible for meta-analysis.

RESULTS

Overall, GSTT1 null genotype was significantly associated with increased risk of gastric cancer (Random-effect OR = 1.23, 95%CI 1.13-1.35, P OR <0.001, I(2) = 45.5%). Significant association was also found in Caucasians, East Asians, and Indians (P Caucasians = 0.010; P East Asians = 0.003; P Indians = 0.017). After adjusting for other confounding variables, GSTT1 null genotype was also significantly associated with increased risk of gastric cancer (Random-effect OR = 1.43, 95%CI 1.20-1.71, P OR <0.001, I(2) = 48.1%).

CONCLUSION

The meta-analysis provides strong evidence for the significant association between GSTT1 null genotype and increased risk of gastric cancer.

CYP2E1 RsaI/PstI polymorphism and gastric cancer susceptibility: meta-analyses based on 24 case-control studies

Background

Previous reports implicate CYP2E1 RsaI/PstI polymorphism as a possible risk factor for several cancers. Published studies on the relationship of CYP2E1 RsaI/PstI polymorphisms with the susceptibility to gastric cancer are controversial. This study aimed to determine this relationship accurately.

Methods

Meta-analyses that assessed the association of CYP2E1 RsaI/PstI variations with gastric cancer were conducted. Subgroup analyses on ethnicity, smoking status, alcohol consumption, and source of controls were also performed. Eligible studies up to Mar 2012 were identified.

Results

After rigorous searching and screening, 24 case-control studies comprising 3022 cases and 4635 controls were selected for analysis. The overall data failed to indicate the significant associations of CYP2E1 RsaI/PstI polymorphisms with the gastric cancer risk [c2 vs. c1: odds ratio (OR) = 1.06; 95% confidence interval (CI) = 0.88–1.28; c2c2 vs. c1c1: OR = 1.23; 95% CI = 0.78–1.92; c2c2+c1c2 vs. c1c1: OR = 0.93; 95% CI = 0.79–1.10]. Similar results were observed in the subgroup analyses on ethnicity, drinking status, and source of controls. However, in the subgroup analysis on smoking status, a borderline increase in cancer risk was found among long-term smokers (c2c2+c1c2 vs. c1c1: OR = 1.39; 95% CI = 1.00–1.92).

Conclusion

CYP2E1 RsaI/PstI polymorphisms may modify the susceptibility to gastric cancer among individuals who have a smoking history. Large and well-designed studies are needed to confirm this conclusion.

A case-control study on the effect of Apolipoprotein E genotypes on gastric cancer risk and progression

Background

Apolipoprotein E (ApoE) is a multifunctional protein playing both a key role in the metabolism of cholesterol and triglycerides, and in tissue repair and inflammation. The ApoE gene (19q13.2) has three major isoforms encoded by ε2, ε3 and ε4 alleles with the ε4 allele associated with hypercholesterolemia and the ε2 allele with the opposite effect. An inverse relationship between cholesterol levels and gastric cancer (GC) has been previously reported, although the relationship between apoE genotypes and GC has not been explored so far.

Methods

One hundred and fifty-six gastric cancer cases and 444 hospital controls were genotyped for apoE polymorphism (ε2, ε3, ε4 alleles). The relationship between GC and putative risk factors was measured using the adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) from logistic regression analysis. A gene-environment interaction analysis was performed. The effect of the apoE genotypes on survival from GC was explored by a Kaplan–Meier analysis and Cox proportional hazard regression model.

Results

Subjects carrying at least one apoE ε2 allele have a significant 60% decrease of GC risk (OR=0.40, 95% CI: 0.19 – 0.84) compared with ε3 homozygotes. No significant interaction emerged between the ε4 or ε2 allele and environmental exposures, nor ε2 or ε4 alleles affected the median survival times, even after correcting for age, gender and stadium.

Conclusions

Our study reports for the first time a protective effect of the ε2 allele against GC, that might be partly attributed to the higher antioxidant properties of ε2 compared with the ε3 or ε4 alleles. Given the study’s sample size, further studies are required to confirm our findings.

Relevance of GSTM1, GSTT1, and GSTP1 gene polymorphisms to gastric cancer susceptibility and phenotype

Human glutathione S-transferases (GSTs) are phase II metabolizing enzymes that play a key role in protecting against cancer by detoxifying numerous potentially cytotoxic/genotoxic compounds. The genes encoding the human GST isoenzymes GSTM(mu)1, GSTT(theta)1 and GSTP(pi)1 harbour polymorphisms, which have been considered important modifiers of the individual risk for environmentally induced cancers such as gastric cancer (GC). However, results are inconsistent among studies from different geographic areas and ethnic groups. Our goal was to perform a nationwide, case-control study in Spain to evaluate the relevance of several functional GST gene polymorphisms and environmental factors to GC risk and phenotype. DNA from 557 GC patients and 557 sex- and age-matched healthy controls (HC) was typed for two deletions in the GSTM1 and GSTT1 genes and two SNPs in the GSTP1 gene (rs1695 and rs1138272) using polymerase chain reaction-restriction fragment length polymorphism methods. Logistic regression analysis identified Helicobacter pylori infection with CagA strains [odds ratio (OR): 2.36; 95% confidence interval (CI): 1.78-3.15], smoking habit (OR: 2.10; 95% CI: 1.48-2.97) and family history of GC (OR: 3.2; 95% CI: 2.02-5.16) as independent risk factors for GC. No differences in the frequencies of GSTM1 or GSTT1 null genotypes were observed between cases and controls (GSTM1: 50.8% vs. 48%; GSTT1: 21.5% vs. 21%). Moreover, simultaneous carriage of both, the GSTM1 and the GSTT1 null genotypes, was almost identical in both groups (10.7% in GC vs. 10.6% in HC). In addition, no significant differences in GSTP1 Ile105Val (rs1695) and GSTP1 Val114Ala (rs1138272) genotype distribution were observed between GC patients and controls. Subgroup analysis for age, gender, Helicobacter pylori status, smoking habits, family history of GC, anatomic location and histological subtype revealed no significant association between GST variants and GC risk. Our results show that the GST polymorphisms evaluated in this study are not relevant when determining the individual susceptibility to GC or phenotype in a South-European population.

Smoking, alcohol consumption, and the risk of amyotrophic lateral sclerosis: a population-based study

Smoking has been posited as a possible risk factor for amyotrophic lateral sclerosis (ALS), but large population-based studies of patients with incident disease are still needed. The authors performed a population-based case-control study in the Netherlands between 2006 and 2009, including 494 patients with incident ALS and 1,599 controls. To prove the relevance of population-based incidence cohorts in case-control studies, the authors compared results with those from cohorts including patients with prevalent ALS and referral patients. Subjects were sent a questionnaire. Multivariate analyses showed an increased risk of ALS among current smokers (odds ratio = 1.38, 95% confidence interval (CI): 1.02, 1.88) in the incident patient group only. Cox regression models showed that current smoking was also independently associated with shorter survival (hazard ratio = 1.51, 95% CI: 1.07, 2.15), explaining the lack of association in the prevalent and referral patient groups. Current alcohol consumption was associated with a reduced risk of ALS (incident patient group: odds ratio = 0.52, 95% CI: 0.40, 0.75). These findings indicate that current smoking is associated with an increased risk of ALS, as well as a worse prognosis, and alcohol consumption is associated with a reduced risk of ALS, further corroborating the role of lifestyle factors in the pathogenesis of ALS. The importance of population-based incident patient cohorts in identifying risk factors is highlighted by this study.

Meta-analysis of the association of CYP1A1 polymorphisms with gastric cancer susceptibility and interaction with tobacco smoking

The association of two cytochrome P4501A1 (CYP1A1) polymorphisms, m1 (T6235C transition) and m2 (A4889G transition), with gastric cancer risk is inconclusive. We conducted a meta-analysis of all available studies to evaluate the potential role of the polymorphisms and their interactions with tobacco smoking in gastric cancer susceptibility. Published literature from PubMed was retrieved by two investigators independently. Fourteen case-control studies with 2,032 gastric cancer cases and 5,099 controls were selected. A fixed effects model or a random-effects model was used to estimate the odds ratio (OR) for the CYP1A1 polymorphisms and the occurrence of gastric cancer. Significant associations between CYP1A1 m1 and m2 polymorphisms and gastric cancer susceptibility were not observed in all genetic models in the overall analyses. Subgroup analyses by ethnicity and source of controls did not reveal significant associations with gastric cancer risk. Stratification analysis by smoking status found that carriers of the heterozygous and homozygous m1 genotypes decreased the susceptibility of gastric cancer among ever-smokers (pooled OR = 0.56, 95 % CI 0.36-0.89, fixed effects). In contrast, the m2 genotypes (G/G and A/G) did not show any relevance to gastric cancer risk among the smoking population (pooled OR = 1.30, 95 % CI 0.84-2.00, fixed effects). Overall, we found that the CYP1A1 polymorphism itself, either m1 or m2, did not represent an independent genetic risk factor influencing gastric cancer. However, subgroup analyses suggest that carriers of the heterozygous and homozygous m1 genotype who are exposed to tobacco smoke have a significantly lower risk of developing gastric cancer. To explain the observed reduction of gastric cancer risk, we proposed a novel hypothesis of "observation bias". This hypothesis is also applicable to explain the combined effects of other genetic polymorphisms and environmental factors on the risk of developing cancers, and the rationality of the hypothesis needs to be further investigated.