Genetic polymorphisms inGSTM1,GSTT1,GSTP1,GSTM3and the susceptibility to gallbladder cancer in North India

Gallbladder cancer: Progress in the Indian subcontinent

Gallbladder cancer (GBC) is one of the commonest biliary malignancies seen in India, Argentina, and Japan. The disease has dismal outcome as it is detected quite late due to nonspecific symptoms and signs. Early detection is the only way to improve the outcome. There have been several advances in basic as well as clinical research in the hepatobiliary and pancreatic diseases in the West and other developed countries but not enough has been done in GBC. Therefore, it is important and the responsibility of the countries with high burden of GBC to find solutions to the many unanswered questions like etiopathogenesis, early diagnosis, treatment, and prognostication. As India being one of the largest hubs for GBC in the world, it is important to know how the country has progressed on GBC. In this review, we will discuss the outcome of the publications from India highlighting the work and the developments taken place in past several decades both in basic and clinical research.

GSTs genetic polymorphism, gene-environment interaction and association with gallbladder cancer risk in North Indian population: A case-controlled study

AIM

In the present case-controlled study, we explored the role of genetic polymorphism in three xenobiotic metabolizing genes, GSTM1, GSTT1 and GSTP1, and their association to gallbladder cancer (GBC) risk in a North Indian population. Its etiology is influenced by genetic, food habits, lifestyle, and environmental factors. GBC incidence is significantly higher in the Gangetic belt, India. Therefore, we explored the prognostic factors in the susceptibility of GBC through gene-gene and gene-environment interaction in this region.

MATERIAL AND METHODS

Genetic polymorphism was analyzed in 108 GBC patients from Kamala Nehru Memorial Cancer Hospital, Prayagraj and 142 matched controls. GSTM1 and GSTT1 genotypes were analyzed by multiplex PCR method, while restriction fragment length polymorphism (RFLP) was performed to analyze GSTP1 genotypes. Logistic regression analysis calculating the odds ratio (OR) and 95% confidence interval (CI) was performed to analyze the GBC risk.

RESULTS

GSTT1 (null) genotype was at a significantly higher risk and susceptible to GBC (OR = 2.044, CI = 1.225-3.411, P = 0.006), while GSTM1 and GSTP1 genotypes did not show any association to GBC risk. After sex stratification, females diagnosed with GBC had higher GSTT1 (null) genotype (OR = 2.754, CI = 1.428-5.310, P = 0.003) compared to males. GBC patients dwelling in rural areas show higher GSTT1 (null) genotype with two-fold GBC risk (OR = 2.031, CI = 1.200-3.439, P = 0.008). Further, GBC patients with histopathology of adenocarcinoma also showed higher GSTT1 (null) genotype (OR = 2.113, CI = 1.248-3.578, P = 0.005). Gene-gene interaction between GSTT1 (non-null)/GSTP1 (Ile/Val + Val/Val), enhance the GBC risk (OR = 1.840, CI = 1.135-2.982, P = 0.013).

CONCLUSIONS

The present study suggests that GSTT1 (null) genotype has higher susceptibility and risk towards GBC in North Indian population. Female patients, patients with histopathology of adenocarcinoma and rural dwelling GBC patients have higher GSTT1 (null) genotypes and may be at risk of developing GBC. The genotype combination GSTT1 (non-null)/GSTP1 (Ile/Val + Val/Val) has increased GBC susceptibility and may be considered as 'at risk' genotypes for GBC in North Indians.

Glutathione S-transferase, catalase, and mitochondrial superoxide dismutase gene polymorphisms modulate redox potential in systemic lupus erythematosus patients from Manaus, Amazonas, Brazil

OBJECTIVE

To investigate the frequency of glutathione S-transferase (GST), catalase, and SOD2 genetic polymorphisms and their correlation with SLE.

METHODS

A total of 290 females (patients = 151; controls= 139) were recruited. Multiplex PCR was performed for genotyping GSTM1 and GSTT1 genes, whereas real-time qPCR was used for determination of SNPs: CAT C262T, SOD2 C47T, GSTP1 A313G and GSTP1 IVS6 -C16T.

RESULTS

Thiol levels are decreased in SLE patients (p<0.001), while MDA levels were significantly higher (p<0.001) and those carrying the polymorphisms had higher rates of oxidative stress. Patients with double null deletion GSTT1^null/GSTM1^null had a frequency almost five times higher than the controls (p<0.001, OR 4.81, CI 1.98-12.11). SLE patients had a lower wild-type frequency of SOD2^CC allele compared to controls (12.4% vs 27.3%). Statistical significances were observed on the association between the GSTT1^null and GSTM1^null with SOD2^mut (p<0.001, OR 0.15, CI 0.05-0.47), with GSTP1 A303G (p=0.012, OR 0.19, CI 0.05-0.69), and with GSTP1 IVS6 (p=0.008, OR 0.14, CI 0.03-0.63). The same was observed between SOD2 C47T with GSTP1 A303G (p=0.09, OR 0.27, CI 0.09-0.74) and GSTP1 IVS6 (p=0.036, OR 0.41, CI 0.18-0.92).

CONCLUSIONS

The deletion GSTT1^null/GSTM1^null may contribute to the increased of the oxidative stress in SLE patients. Isolated GSTP1 and CAT polymorphisms do not seem to influence the increased oxidative stress, neither SLE clinical manifestations. SOD2 47^CT/TT allele may have greater oxidative stress due to structural change in the protein and decreased H₂O₂ production. The combination of polymorphic genes may be involved in the pathogenesis of the disease. Key points • Major question of our paper: Many studies have shown that the antioxidant status levels are decreased in patients with SLE, especially in severe stages of disease. We believe that this paper will be of interest to the readership of your journal had the involvement of polymorphisms and mutations in several genes that contribute to the genetic etiology of SLE, suggesting that these may influence the mechanisms of disease. • Our results. Thiol level was significantly (p<.001) lower and MDA level significantly increased (p<.001) among SLE patients. Those carrying the polymorphisms had higher rates of oxidative stress. SLE Patients had a frequency almost five times higher of double null deletion GSTT1null/GSTM1null than the controls. SLE Patients had a lower wild type frequency of SOD2CC allele compared to controls (12.4% vs 27.3%). We believed the deletion GSTT1null/GSTM1null may contribute to the increased of the oxidative stress in SLE patients while carriers of the mutant SOD2 47CT/TT allele may have greater oxidative stress due to structural change in the protein and decreased H2O2 production. The combination of polymorphic genes may be involved in the pathogenesis of the disease. • Implications of our results: Evidence for the involvement of genetic factors in severe clinical to lupus is compelling. This manuscript shows genetic insights in pathogenic pathways that may lead to severe clinical implications to LES. Therefore, it is necessary to understand their impact on overall disease pathogenesis and prognosis in these patients. We understand from general consensus about environmental factors can modify disease, however, maybe just in individuals who have a permissive genetic background. Even that no single gene predisposes some individuals to LES, we believe the genetic factors described in this manuscript are important elements in susceptibility to severe clinical to LES.

Current and New Biomarkers for Early Detection, Prognostic Stratification, and Management of Gallbladder Cancer Patients

Gallbladder cancer (GBC) is an aggressive disease that shows evident geographic variation and is characterized by a poor prognosis, mainly due to the late diagnosis and ineffective treatment. Genetic variants associated with GBC susceptibility, including polymorphisms within the toll-like receptors TLR2 and TLR4, the cytochrome P450 1A1 (CYP1A1), and the ATP-binding cassette (ABC) transporter ABCG8 genes, represent promising biomarkers for the stratification of patients at higher risk of GBC; thus, showing potential to prioritize cholecystectomy, particularly considering that early diagnosis is difficult due to the absence of specific signs and symptoms. Similarly, our better understanding of the gallbladder carcinogenic processes has led to identify several cellular and molecular events that may influence patient management, including HER2 aberrations, high tumor mutational burden, microsatellite instability, among others. Despite these reports on interesting and promising markers for risk assessment, diagnosis, and prognosis; there is an unmet need for reliable and validated biomarkers that can improve the management of GBC patients and support clinical decision-making. This review article examines the most potentially significant biomarkers of susceptibility, diagnosis, prognosis, and therapy selection for GBC patients, highlighting the need to find and validate existing and new molecular biomarkers to improve patient outcomes.

GSTM3 Function and Polymorphism in Cancer: Emerging but Promising

Cancer is a major cause of human mortality; however, the molecular mechanisms and proteomic biomarkers that cause tumor progression in malignant tumors are either unknown or only partially revealed. Glutathione S-transferases mu3 (GSTM3), which belongs to a family of xenobiotic detoxifying phase II enzymes, is associated with carcinogen detoxification and the metabolism of exogenous electrophilic substances. It has been reported that GSTM3 has different polymorphisms in various tumor cells and regulates tumorigenesis, cell invasion, metastasis, chemoresistance, and oxidative stress. Deep research into the regulatory mechanisms involved in disorders of GSTM3 expression and the function of GSTM3 in different cancers may facilitate improvements in cancer prevention and targeted therapy. The combination of GSTM3 with other family members can regulate the carcinogenesis and susceptibility to different cancers in humans. GSTM3 also regulates the reactive oxygen species (ROS) and participates in oxidative stress-mediated pathology. Here, we provide a general introduction to GSTM3 in order to better understand the role of GSTM3 in cancer.

Comparison of short- and long-term outcomes between anatomical subtypes of resected biliary tract cancer in a Western high-volume center

BACKGROUND

Outcomes for the four anatomical subtypes of biliary tract carcinoma (BTC) - intrahepatic, perihilar and distal cholangiocarcinoma (ICC, PHCC, DCC) and gallbladder carcinoma (GBC) - are often combined. However, large cohorts comparing short- and long-term outcomes for the anatomical subtypes of BTC are lacking.

METHODS

All patients who underwent resection for pathology proven ICC, PHCC, DCC or GBC (2000-2016) from a single Western high-volume center were retrospectively selected. Clinicopathological characteristics, short- and long-term outcomes were compared between the four anatomical subtypes.

RESULTS

Overall, 361 patients with resected BTC were included (33 ICC, 135 PHCC, 148 DCC, 45 GBC). Clavien-Dindo grade III or higher complications were 48%, 51%, 36% and 8% (p < 0.001) and 90-day mortality was 9%, 15%, 3%, 4% (p < 0.001), for ICC, PHCC, DCC, GBC. Median overall survival was 37, 42, 29 and 41 months (p = 0.722), for ICC, PHCC, DCC, GBC. Five-year survival ranged between 29% and 37%. Anatomical subtype was not an independent predictor for overall survival.

CONCLUSION

In this large single-center cohort of resected BTC, major morbidity and 90-day mortality varied between the four anatomical subtypes of BTC, mainly due to differences in surgical approach However, a significant difference in overall survival was not detected.

Carcinogen Metabolism Pathway and Tumor Suppressor Gene Polymorphisms and Gallbladder Cancer Risk in North Indians: A Hospital-Based Case-Control Study

Background:

Carcinogen metabolism pathway and tumor suppressor gene polymorphisms have been reported to be associated with increased gallbladder cancer risk. However, the association of genetic variants and gallbladder cancer risk in Indians are not well studied. We examined whether genetic polymorphisms of metabolic enzymes cytochrome P450 1A1 and glutathione S-transferase and tumor suppressor gene p53 (TP53) are associated with an increased risk of gallbladder cancer in North Indians.

Methods:

This hospital-based case-control study was conducted in 96 gallbladder cancer patients with gallstones (cases) and 93 cholelithiasis patients (controls) at the Sanjay Gandhi Postgraduate Institute of Medical Sciences in Lucknow, India from July 2014 through May 2017. Genomic DNA was extracted from white blood cells of each patient using a simple salting-out procedure. The genotypic frequencies of CYP1A1 rs4646903, CYP1A1 rs1048943, and TP53 rs1042522 polymorphisms were investigated using TaqMan SNP Genotyping Assay and GSTM1 and GSTT1 polymorphisms were analyzed using the multiplex PCR assay.

Results:

The frequency of CC genotype of TP53 rs1042522 polymorphism was 27.1% (26/96) in cases and 12.9% (12/93) in controls. The CC genotype was associated with an increased risk of gallbladder cancer in North Indians (age- and sex-adjusted odds ratio, 2.81; 95% confidence interval, 1.19–6.61; P = 0.02). No significant differences in genotypic and allelic frequencies of the metabolic pathway gene polymorphisms were found between cases and controls.

Conclusions:

Our data provide preliminary evidence that the CC genotype of the TP53 rs1042522 polymorphism may be associated with an increased risk of gallbladder cancer in North Indians.

Role of Glutathione-S-Transferases in Gallbladder Cancer and Cholelithiasis Susceptibility and Meta-Analysis

Glutathione-S-transferase T1 (GSTT1) and glutathione-S-transferase M1 (GSTM1) genes are associated with increase susceptibility to developing different types of cancers. The aim of present study was to investigate the role of genetic variants of GSTM1 and GSTT1 in gallbladder cancer (GBC) and cholelithiasis in Kashmir valley. Genotyping was done by multiplex polymerase chain reaction in 100 GBC, 100 cholelithiasis, and 150 controls adjusted by age and sex. We also performed a meta-analysis of published studies on GSTM1 and GSTT1 to evaluate the association between the GSTM1 and GSTT1 polymorphisms and GBC. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using random- or fixed-effects model. In the present study, no association was observed between GSTM1 null and GSTT1 null genotypes and GBC and cholelithiasis. Meta-analysis results showed that GSTM1 null genotype was associated with GBC risk (P = 0.042). Subgroup analysis by ethnicity showed that GSTM1 null (P = 0.024) and GSTT1 null genotype (P = 0.037) were significantly associated with risk of GBC in Asians. This is the first study to investigate the role of genetic variants of GSTM1 and GSTT1 in GBC in Kashmir valley and cholelithiasis in the world.

Through oxaliplatin resistance induction in colorectal cancer cells, increasing ABCB1 level accompanies decreasing level of miR-302c-5p, miR-3664-5p and miR-129-5p

Oxaliplatin as a component of (Neo-) adjuvant chemotherapeutic regimens is administered to colorectal cancer patients. Unfortunately, the acquisition of resistance to this drug in nearly 90% of metastatic patients rendered it as an ineffective drug. Therefore, resistance mechanisms to this drug should be elucidated. There are different genes like GSTP1 and ABCB1 which are responsible for oxaliplatin resistance. We hypothesized that miR-129-5p, miR-302c-5p, miR-3664-5p, mir-3714 and miR-513a-3p are targeting ABCB1 gene, while GSTP1 was predicted to be the potential target of miR-3664-5p, mir-3714 and miR-513a-3p. In order to study this hypothesis, resistant colorectal cell lines were generated through intermittent exposure of HCT116, SW480 and HT29 to the increasing doses of oxaliplatin. MTT assays validated this resistance induction. Expression of ABCB1 and GSTP1 in addition to their targeting miRNAs in different cell lines were studied by quantitative real time PCR in the cell lines. Even though in comparison with HCT116 and SW480 cell lines, GSTP1 expression was reduced in resistant cells, ABCB1 expression was upregulated in these cell lines. On the other hand, HT-29 resistant cells showed elevated GSTP1 and unchanged ABCB1 levels. While miR-302c-5p level was downregulated in resistant cell lines, miR-129-5p and miR-3664-5p level showed different pattern of reduction in the resistant SW480 and HCT116 cell lines. GSTP1 level was correlated directly with miR-513a-3p and miR-3664-5p in all SW480 and HCT116 derived cell lines, however in HT-29-OXR1, GSTP1 level was correlated inversely with miR-3664-5p. In conclusion, upregulation of ABCB1 can be considered as the crucial component of poor response to oxaliplatin which is likely controlled by miR-302c-5p.

Glutathione S-Transferase P1 313 (A > G) Ile105Val Polymorphism Contributes to Cancer Susceptibility in Indian Population: A Meta-analysis of 39 Case-Control Studies

GSTP1 involved in the metabolism of carcinogens and toxins, reduces damage of DNA and act as a suppressor of carcinogenesis. Many studies have reported that 313 A > G polymorphism is associated with different cancer in Indian population, but the results remain conflicting rather than conclusive. Therefore, we have performed meta-analysis to clarify the more precise association of GSPT1 313 A > G polymorphism with cancer risk in Indian population. We retrieved all relevant published literature from PubMed (Medline) and Google scholar web database and included those study only based on the established inclusion criteria. Pooled ORs and 95% CIs were used to appraise the strength of association. Publication bias and sensitivity analysis was also evaluated. A total of 6581 confirmed cancer cases and 8218 controls were included from eligible thirty nine case-controls studies. Pooled analysis suggested that the variant genotypes significantly increased the risk of cancer in allele (G vs. A: OR 1.266, 95% CI 1.129-1.418, p = 0.001), heterozygous (AG vs. AA: OR 1.191, 95% CI 1.047-1.355, p = 0.008), homozygous (GG vs. AA: OR 1.811, 95% CI 1.428-2.297, p = 0.001), dominant (GG + AG vs. AA: OR 1.276, 95% CI 1.110-1.466, p = 0.001) and recessive (GG vs. AG + AA: OR 1.638, 95% CI 1.340-2.002, p = 0.001) genetic models. The stability of these observations was confirmed by a sensitivity analysis. Begger's funnel plot and Egger's test did not reveal any publication bias. This meta-analysis suggests that the GSTP1 313 A > G polymorphism may contribute to genetic susceptibility to cancer in Indian population. However, larger studies and randomized clinical trial will be required to elucidate the biological and molecular mechanism of GSTP1 gene in cancer.

Genetic landscape of gallbladder cancer: Global overview

Gallbladder cancer (GBC) is a rare malignancy of biliary tract cancer (BTC), characterized by late presentation and poor prognosis. It exhibits wide geographical as well as ethnical variations. So, diverse epidemiology along with etiological factors have been discussed in the current article. Present review unravels the germ line polymorphisms contributing to GBC susceptibility through candidate gene approach and GWAS. GBC is enriched with multiple mutations consisting of both passenger and driver mutations. The identification of the hotspot driver mutations which are involved in the etiopathogenesis of this cancer is necessary, before targeted therapies could be implemented clinically. Thus, this review sheds lights on both traditional low throughput methods along with high throughput NGS used to determine somatic mutations in cancer. With the advent of GWAS and high throughput sequencing methods, it is possible to comprehend the mutational landscape of this enigmatic disease. This article is the first one to provide insights into the genetic heterogeneity of GBC along with somatic mutational data from Catalogue of Somatic Mutations in Cancer (COSMIC) database. In addition, management of tumor heterogeneity as a therapeutic challenge has been discussed. Future goals involve liquid biopsy based research for better clinical management of the disease. Therefore, research efforts involving discovery of non- invasive markers for early stage cancer detection along with novel therapies should be directed.

Genetic Polymorphism of the Glutathione S-transferase Pi 1 (GSTP1) and Susceptibility to Cervical Cancer in Human Papilloma Virus Infected Northeastern Thai Women

Objective:

We aimed to investigate any association between a genetic polymorphism of the detoxification GSTP1 gene and risk of cervical cancer in northeastern Thailand.

Materials and Methods:

Genotyping of GSTP1 was performed for 198 squamous cell cervical cancer (SCCA) patients and 198 age-matched healthy controls with the PCR-RFLP method.

Results:

The respective frequencies of the G allele were 0.33 and 0.26 in the controls and cases, the difference being significant (OR = 0.69 [95% CI: 0.50-0.95, p=0.0192]). Among women infected with high-risk types of HPV, being a heterozygous carrier was associated with a reduced risk of cervical cancer (adjusted OR = 0.32 [95% CI: 0.12-0.91, p=0.031]). Similarly, a decreased risk was observed in heterozygous women with a non-smoking partner (adjusted OR = 0.27 [95% CI: 0.09-0.83, p=0.023]).

Conclusions:

GSTP1 polymorphism could influence susceptibility to cervical cancer among northeast Thai women; either as a independent factor or in combination with high-risk HPV infection. Dual-testing of HPV and the GSTP1 might prove an effective screening tool for cervical cancer.

Rapid Detection of the GSTM3 A/B Polymorphism Using Real-time PCR with TaqMan(®) Probes

Glutathione S-transferases (GSTs) are a group of phase II detoxification enzymes, which catalyze the conjugation of glutathione (GSH) with carcinogens, among other xenobiotics. The GSTM3 gene is part of the GSTs gene family, and its polymorphism A/B has been associated with risk and protective effects of several cancers. This genetic variant is a deletion of 3 bp (AGG) in intron 6. Previous association studies have performed genotyping using techniques such as polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In this study, we took advantage of the TaqMan(®) probes features and developed a reliable, faster, more simple and economic method to identify the 3-bp deletion. Our allelic discrimination method was able to distinguish between homozygous A/A, heterozygous A/B and homozygous B/B samples, as shown by TaqMan(®) based real-time PCR. Results were validated by Sanger Sequencing. In conclusion, we developed a specific and rapid method to detect the 3-bp deletion from the GSTM3 A/B polymorphism.

Variants and haplotypes in Flap endonuclease 1 and risk of gallbladder cancer and gallstones: a population-based study in China

The role of FEN1 genetic variants on gallstone and gallbladder cancer susceptibility is unknown. FEN1 SNPs were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method in blood samples from 341 gallbladder cancer patients and 339 healthy controls. The distribution of FEN1-69G > A genotypes among controls (AA, 20.6%; GA, 47.2% and GG 32.2%) was significantly different from that among gallbladder cancer cases (AA, 11.1%; GA, 48.1% and GG, 40.8%), significantly increased association with gallbladder cancer was observed for subjects with both the FEN1-69G > A GA (OR = 1.73, 95% CI = 1.01-2.63) and the FEN1-69G > A GG (OR = 2.29, 95% CI = 1.31-3.9). The distribution of FEN1 -4150T genotypes among controls (TT, 21.8%;GT, 49.3% and GG 28.9%) was significantly different from that among gallbladder cancer cases (TT, 12.9%; GT, 48.4% and GG 38.7%), significantly increased association with gallbladder cancer was observed for subjects with both the FEN1-4150T GT(OR = 1.93, 95% CI = 1.04-2.91) and the FEN1-4150T GG(OR = 2.56, 95% CI = 1.37-5.39). A significant trend towards increased association with gallbladder cancer was observed with potentially higher-risk FEN1-69G > A genotypes (P < 0.001, χ2 trend test) and FEN14150G > T (P < 0.001, χ2 trend test) in gallstone presence but not in gallstone absence (P = 0.81, P = 0.89, respectively). In conclusion, this study revealed firstly that FEN1 polymorphisms and haplotypes are associated with gallbladder cancer risk.

Expression of CCK Receptors in Carcinoma Gallbladder and Cholelithiasis: A Pilot Study

BACKGROUND

Gastrin and cholecystokinin (CCK) receptors are trophic for various gastrointestinal malignancies. Their role in gallbladder cancer has not been widely studied.

OBJECTIVES

To identify expression of CCK-A and CCK-B receptors in the tissue and blood of patients suffering from carcinoma (CA) gallbladder and gallstone disease and to compare expression of CCK A and B receptors in the gall bladder tissue and blood of healthy individuals and patients of CA gallbladder, and gallstone diseases.

MATERIALS AND METHODS

Forty nine subjects of both genders were recruited, comprising of 22 patients of CA gall bladder, 19 cases of cholelithiasis and, 8 normal gallbladders obtained from patients operated for trauma of the biliary system or Whipple's procedure. RNA extraction and cDNA formation for CCK-A and CCK-B receptors were carried out. Real Time PCR was performed on cDNA and threshold cycle (Ct) value of each sample was obtained and ΔCt was calculated. Chi-square test for comparing two groups and ANOVA test for comparing multiple groups were applied and if p<0.05 then Dunnett-C test was performed.

OBSERVATION AND RESULTS

Both CCK-A and CCK-B receptors were expressed irrespective of its origin in all tissues and blood samples studied; be it normal, Cholelithiasis or CA gallbladder and there was no difference among them (p>0.05).

CONCLUSION

This preliminary study showed higher expression of CCK-A receptors in patients of cholelithiasis and decreased expression of CCK-A receptors in patients of CA gallbladder as compared to normal gallbladder although it did not rise to statistical significance.

Upregulated plasma and urinary levels of nucleosides as biological markers in the diagnosis of primary gallbladder cancer

We first detected aberrant nucleoside levels in the plasma, urine, bile, and tissues from cases and controls to explore them as biomarkers in the diagnosis of gallbladder cancer. Reversed-phase high-performance liquid chromatography was used to assess the levels of ten nucleosides in these samples from gallbladder cancer patients, gallstone patients, and healthy controls. Plasma and urine samples were collected from patients with gallbladder cancer (n = 202), patients with gallstones (n = 203), and healthy controls (n = 205); bile and tissue samples were collected from 91 gallbladder cancer patients, 93 gallstone patients; and 90 were donated after cardiac death. Of the ten nucleosides analyzed, eight urinary nucleosides, five plasma nucleosides, three bile nucleosides, and one tissue nucleoside were significantly upregulated in the gallbladder cancer patients compared to control groups (p < 0.05). Among these upregulated nucleosides, the sensitivity, specificity, and accuracy of urinary nucleosides in the diagnosis of gallbladder cancer patients were 89.4, 97.1, and 95.7%, respectively, those of plasma nucleosides were 91.2, 95.6, and 94.2%, respectively, those of bile nucleosides were 95.3, 96.4, and 95.1%, respectively, and those of tissue nucleosides were 86.2, 93.8, and 92.6%, respectively. These results suggest that nucleosides may be as useful as biological markers for gallbladder cancer.

Clinical significance of P-glycoprotein and glutathione S-transferase π expression in gallbladder carcinoma

P-glycoprotein (P-gp) and glutathione S-transferase π (GST-π) are not only drug-resistance markers, but also prognostic markers of various cancers. The aim of the present study was to investigate the clinical significance of P-gp and GST-π in gallbladder carcinoma (GBC). Tissue samples from 42 patients with GBC were immunostained. Demographic, clinical and follow-up data were collected and analyzed. The positive expression rates of P-gp and GST-π in the GBC tissues were significantly higher (76.2 and 64.3%, respectively) than that of chronic cholecystitis specimens (30 and 20%, respectively) (P=0.014 and 0.035, respectively), and correlated with the Nevin stage of GBC. Multivariate analysis demonstrated that patients with positive expression of P-gp and GST-π showed a significantly lower 2-year survival rate (11.1 and 12%, respectively) compared with patients with negative expression (55.6 and 45.5%, respectively) (P=0.013 and 0.036, respectively). P-gp was also found to be an independent prognostic marker of 2-year survival rate by logistic regression analysis (B=-2.76, P=0.061). Results of this study suggest that P-gp is a prognostic marker of GBC and the detection of P-gp and GST-π may contribute to the prognosis of GBC and the application of chemotherapy as a therapeutic treatment.

GSTM3 A/B polymorphism and risk for head and neck cancer: a meta-analysis

Background

Glutathione S-transferase M3 (GSTM3) is an important member of the GSTs that plays a critical role in the development of head and neck cancer (HNC). Several studies have investigated between the GSTM3 A/B polymorphism and risk of HNC, however, the results remain controversial. The aim of this meta-analysis is to evaluate the association between the GSTM3 A/B polymorphism and the risk of HNC.

Methods

All eligible case-control studies published up to July 2013 were identified by searching PubMed and Web of Science. The HNC risk associated with the GSTM3 A/B polymorphism was estimated for each study by odds ratios (OR) together with its 95% confidence interval (CI), respectively.

Results

Fourteen studies from ten publications with 2110 patients and 2259 controls were included. Overall, the GSTM3 A/B polymorphism was associated with a decreased risk of HNC using the dominant model, homozygote comparison model and heterozygote comparison model (OR = 0.82, 95%CI: 0.71–0.94; OR = 0.67, 95%CI: 0.49–0.94; and OR = 0.84, 95%CI: 0.73–0.97, respectively); besides, in stratification analyses by ethnicity, similar results were observed in Caucasian populations. Stratification by tumor site indicated that the GSTM3 polymorphism was associated with a decreased risk of laryngeal cancer under recessive model and homozygote comparison (OR = 0.52, 95%CI: 0.30–0.89; and OR = 0.50, 95%CI: 0.29–0.87, respectively); By stratifying source of control, decreased cancer risk was observed in hospital-based population under all genetic models (OR = 0.67, 95%CI: 0.56–0.81 for the dominant model; OR = 0.66, 95%CI: 0.46–0.95 for the recessive model; OR = 0.55, 95%CI: 0.37–0.83 for the homozygote comparison model, and OR = 0.70, 95%CI: 0.58–0.84 for the heterozygote comparison model).

Conclusions

This meta-analysis suggests that the GSTM3 A/B polymorphism may be an important protective factor for HNC, especially of laryngeal cancer and Caucasian populations.

Association between glutathione S-transferase M1 null genotype and risk of gallbladder cancer: a meta-analysis

Glutathione S-transferases (GSTs) are a family of enzymes which are involved in the detoxification of potential carcinogens. Glutathione S-transferase M1 (GSTM1) null genotype can impair the enzyme activity of GSTs and is suspected to increase the susceptibility to gallbladder cancer. Previous studies investigating the association between GSTM1 null genotype and risk of gallbladder cancer reported inconsistent findings. To quantify the association between GSTM1 null genotype and risk of gallbladder cancer, we performed a meta-analysis of published studies. We searched PubMed, Embase, and Wanfang databases for all possible studies. We estimated the pooled odds ratio (OR) with its 95% confidence interval (95% CI) to assess the association. Meta-analysis of total included studies showed that GSTM1 null genotype was not associated with gallbladder cancer risk (OR = 1.13, 95% CI 0.88-1.46, P = 0.332). Subgroup analysis by ethnicity showed that there was no association between GSTM1 null genotype and risk of gallbladder cancer in both Caucasians and Asians. However, meta-analysis of studies with adjusted estimations showed that GSTM1 null genotype was associated with increased risk of gallbladder cancer (OR = 1.46, 95% CI 1.02-2.09, P = 0.038). Thus, this meta-analysis shows that GSTM1 null genotype is likely to be associated with risk of gallbladder cancer. More studies with well design and large sample size are needed to further validate the association between GSTM1 null genotype and gallbladder cancer.

GSTM1 copy number and promoter haplotype as predictors for risk of recurrence and/or second primary tumor in patients with head and neck cancer

The objective of this study was to determine copy number variant (CNV) and promoter genetic variants in glutathione S-transferase Mu class 1 (GSTM1) and the risk of recurrence (REC)/second primary tumor (SPT) in patients with previously diagnosed early stage head and neck cancer. Among 441 subjects, 133 experienced REC and/or an SPT, while 308 had single primary disease. TaqMan real-time polymerase chain reaction was used to measure the exact copy number of GSTM1 and direct sequencing was used to determine genetic variants in the GSTM1 promoter region. Multivariate Cox regression analysis was performed to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) associated with copy number and genetic variants. REC/SPT-free survival times were compared by constructing Kaplan–Meier curves and differences between curves were tested by logrank test. Results showed a significantly decreased REC/SPT (HR = 0.57; 95% CI = 0.35–0.95) and longer REC/SPT-free survival in subjects with at least two copies of GSTM1 compared with the GSTM1 homozygous deletion, but not in those with one copy of GSTM1. The −498G, −426G, and −339T alleles were significantly associated with REC/SPT, with HRs of 0.11 (0.02–0.85), 0.28 (0.11–0.74) and 2.02 (1.07–3.82), respectively. Kaplan–Meier survival analysis showed that the −498G, −426G, and −339C alleles were also significantly associated with increased REC/SPT-free survival. Further haplotype analysis showed the haplotype P^{−498G-−426G-−339C} carriers had decreased REC/SPT with a HR of 0.09 (95% CI 0.01–0.71) and increased REC/SPT-free survival compared with those with haplotype P^{−498C-−426A-−339T}. The P^{−498C-−426A-−339T}-containing reporter construct had significantly increased luciferase expression. These results suggest that the GSTM1 CNV and promoter haplotype are better predictors of REC/SPTs of head and neck cancer than just measuring the presence/absence of GSTM1.

Impact of glutathione transferase M1, T1, and P1 gene polymorphisms in the genetic susceptibility of North Indian population to renal cell carcinoma

In this study, we investigated the association of GSTP1, GSTM1, and GSTP1 genetic variants with renal cell carcinoma (RCC) among North Indian patients. The difference in frequency of the GSTT1 null genotype between cases and control subjects was statistically significant (active ver. null, odds ratio [OR]=0.368; confidence intervals [CI] 95%=0.243-0.557, p=0.001). The differences in the frequency of GSTP1 genotypes were statistically significant (AA ver. AG/GG, OR=1.879; CI 95%=0.355-0.797, p=0.002). Higher allelic frequency of the GSTP1 G allele was associated with RCC cases (G ver. A allele, OR=1.534; 95% CI=1.159-2.030, p=0.003). The gene-gene interaction in terms of three-way combination of GSTM1 null, GSTT1 null, and GSTP1 (AG/GG) resulted in 4.5-fold increase in RCC risk (OR=4.452; 95% CI=2.220-9.294). Similarly, our study revealed that GST polymorphism might be a vital determinant of advancement to higher pathological stages and histological grades of RCC. Our findings suggest that genetic variability in members of the GST gene family may be associated with an increased susceptibility to RCC and its progression.

Candidate gene studies in gallbladder cancer: a systematic review and meta-analysis

Gallbladder cancer (GBC) is the most frequent biliary tract malignancy. Wide variations in GBC incidence and familial and epidemiological data suggest involvement of a genetic component in its etiopathogenesis. A systematic review of genetic association studies in GBC was performed by applying a meta-analysis approach and systematically reviewing PubMed database using appropriate terms. Odds ratios (ORs) and 95% confidence intervals (CIs) were appropriately derived for each gene-disease association using fixed and random effect models. Meta-regression with population size and genotyping method was also performed. Study quality was assessed using a 10-point scoring system designed from published guidelines. Following a review of 44 published manuscripts and one unpublished report, 80 candidate gene variants and 173 polymorphisms were analyzed among 1046 cases and 2310 controls. Majority of studies were of intermediate quality. Four polymorphisms with >3 separate studies were included in the meta-analysis [OGG1 (rs1052133), TP53 (rs1042522), CYP1A1 (rs1048943) and GSTM1 null polymorphism]. The meta-analysis demonstrated no significant associations of any of the above polymorphisms with GBC susceptibility except TP53 (rs1042522) polymorphism. To conclude, existing candidate gene studies in GBC susceptibility have so far been insufficient to confirm any association. Future research should focus on a more comprehensive approach utilizing potential gene-gene, gene-environment interactions and high-risk haplotypes.

Association of genetic polymorphism of GSTT1, GSTM1 and GSTM3 in COPD patients in a north Indian population

Environmental exposures and genetic susceptibility can contribute to lung function decline in chronic obstructive pulmonary disease (COPD). Cigarette smoking is the main etiological factor for decline in lung function in COPD. However, only 10-20% chronic smokers develop symptomatic COPD. Genetic susceptibility to COPD might depend upon the variation of enzyme activities that detoxify cigarette smoke components. We performed a case control study to assess the association of Glutathione- S-transferase T1(GSTT1),Glutathione- S-transferase M1 (GSTM1), and Glutathione-S-transferase M3(GSTM3) common polymorphisms with the susceptibility to COPD patient in a north India population. In the present study, the genotypes of 412 subjects, (204 COPD patients and 208 healthy controls) were analyzed. Statistical analysis revealed that the frequency of homozygous GSTM1 null genotype was found to be significant higher in COPD patients as compared with healthy controls (OR, 2.58; 95% CI, 1.73-3.84; P = 0.001), but there were no significant differences in the distribution of homozygous null GSTT1 and 3-bp deletion polymorphism (rs1799735) in intron 6 variant allele in GSTM3 between COPD patients and healthy controls. Our study results suggest that GSTM1 null polymorphism is associated with genetic susceptibility to COPD. Moreover, we also found association between this polymorphism with pulmonary function test in smokers as well as nonsmokers.

Are GSTM1, GSTT1 and CAG repeat length of androgen receptor gene polymorphisms associated with risk of prostate cancer in Iranian patients?

We conducted this study to investigate whether CAG repeat length in androgen receptor gene and GSTM1 and GSTT1 polymorphisms influence prostate cancer risk in Iranian newly diagnosed cancer patients compared to age-matched BPH group and healthy individuals. DNA from 110 pathologically-confirmed prostate cancer patients, 99 age-matched men with Benign Prostatic Hyperplasia (BPH) and 100 healthy individuals were extracted and amplified by polymerase chain reaction (PCR). PCR products were examined by electrophoresis and sequencing. The mean number of CAG repeat in prostate cancer patients was significantly smaller than normal (19.9 vs 22.8; p < 0.0001) and BPH groups (19.9 vs 21.9; P < 0.0001) The mean difference between normal individuals and BPH group was also significant (21.9 vs. 22.8; P = 0.003). Presence of GSTM1 null genotype were significantly higher in cancer and BPH group vs. normal individuals (both P values < 0.0001). there was not seen association between GSTT1 null or positive genotype with cancer risk, but analysis of GSTM1 null and GSTT1 positive in combination was statistically associated with Prostate cancer risk (OR = 8.4, 95% CI 1.53-46.73). Our results showed that CAG repeat polymorphism in AR gene may act as a risk modifier and GSTM1 null genotypes also may be contributed to prostate cancer susceptibility in Iranian patients.

Association of glutathione S-transferase, EPHX, and p53 codon 72 gene polymorphisms with adult acute myeloid leukemia

Polymorphisms in genes encoding detoxification enzymes have been suggested as susceptibility factors for many solid tumors. However, their association with hematological malignancies is controversial. A case-control study was done to determine the association between glutathione S-transferase M1 (GSTM1), GSTT1, GSTP1, EPHX1, and p53 codon 72 polymorphisms as risk factors in 120 adult acute myeloid leukemia (AML) cases and 202 healthy controls by polymerase chain reaction-restriction fragment length polymorphism techniques. Data were analyzed using χ(2) and conditional logistic regression model. None of the polymorphisms studied alone was associated with increased risk for AML. However, the frequency of GSTT1 null genotype was higher among controls (28.7%) than AML cases (21.6%), which showed a protective effect of the null genotype (odds ratio = 0.58, 95% confidence interval: 0.33-1.05, p = 0.07). In a combined analysis, both EPHX1 (His113His) and GSTP1 (Ile/Val) genes imparted a fourfold risk for adult AML but did not reach statistical significance (odds ratio = 4.22, 95% confidence interval: 0.992-17.99, p = 0.05). These findings suggest that the etiology of adult AML cannot be explained by polymorphism at a single locus, perhaps because of complexity involved in the metabolism of diverse xenobiotic compounds, and therefore, multiple gene-gene interactions should be investigated to predict the risk of AML.

Association of GSTM3 intron 6 variant with cigarette smoking, tobacco chewing and alcohol as modifier factors for prostate cancer risk

Variations in glutathione-S-transferases (GSTs) genes may alter the catalytic efficiency of GST isoenzymes leading to potential increase in susceptibility to carcinogens present in cigarette smoke and tobacco. The present study aimed to explore the association of GSTM3 intron 6 polymorphism with susceptibility to prostate cancer (PCa), and to assess risks associated with cigarette smoking, tobacco chewing and alcohol consumption in PCa patients of North India. The study included 135 PCa patients and 169 controls. All subjects were genotyped for 3-bp deletion in intron 6 of GSTM3. Risk of developing prostate cancer associated with GSTM3 AB + BB was 2.5-fold (OR = 2.51, P = 0.028) as compared to AA genotype. Patients who were either smokers and/or had alcohol habits demonstrated a strong association with GSTM3 (AB + BB) genotype (OR = 4.11, P = 0.046; OR = 4.38, P = 0.027, respectively). Our results suggested GSTM3 (AB + BB) genotype to be significantly associated with PCa risk. The risk was even more apparent in case of cigarette smokers and alcohol consumers.

Gallbladder cancer: a morphological and molecular update

Gallbladder cancer (GBC) shows a marked geographical variation in its incidence, with the highest figures being seen in India and Chile and relatively low levels in many Western countries. Risk factors for its development include the presence of gallstones, infection and the presence of an anomalous pancreatobiliary ductal junction. It can arise from either a pathway involving metaplasia or dysplasia or one in which there is a pre-existing adenoma. The former is the more common and, because it is often not associated with a macroscopically recognizable lesion, leads to the recommendation that all gallbladders need to be examined microscopically. Accurate staging of invasive cancers is essential to determine prognosis and treatment, and this requires extensive tumour sampling. A number of genetic alterations have been identified in the preinvasive and invasive stages of GBC and they support the morphological evidence of there being two pathways by which tumours develop. Some of these genetic changes are associated with particular risk factors. For example, cases with anomalous pancreatobiliary ductal junction show a higher frequency of K-ras mutations. Some changes are associated with differences in prognosis. For example, cancers without expression of p21 but with expression for p27 have a better prognosis, whereas those that express c-erb-B2 have a worse one. Work has also been done on identifying clinical, imaging and other factors that indicate that patients have a higher risk of having GBC. This is particularly important in high-incidence areas in which GBC is a significant public health problem.

Role of xenobiotic metabolic enzymes in cancer epidemiology

The cause of the majority of cancers is poorly understood albeit multifactorial. The ultimate consequence of etiological factors where defined is an alteration within the cellular genotype, which is manifested in the cells acquiring malignant phenotype. There are several environmental carcinogens that contribute to carcinogenesis. These carcinogens are metabolized by a large number of enzymes, including the cyto-chrome P 450 group, glutathione-S-transferase (GST), the uridine glucuronyl transferase (UGT) super-family, alcohol-metabolizing enzymes, sulphatases, etc. These enzymes can either inactivate carcinogens or in some cases generate reactive moieties that lead to carcinogenesis. This review summarises the available evidence regarding the role of xenobiotic metabolic enzymes and their role in cancer epidemiology. The available data and studies have identified correlates between expression of various metabolizing enzymes with risk of malignancies known to be induced by their substrates. The data may have relevance in one population but not for another for a specific malignancy and at times may be conflicting. We believe that with mature data in the future it may be possible to stratify patients by risk.

Cholecystokinin receptor A gene polymorphism in gallstone disease and gallbladder cancer

BACKGROUND AND AIM

Gallbladder carcinoma (GBC) usually arises in the background of gallstone disease which may be causatively related to decreased gallbladder contractility. Cholecystokinin receptor A (CCK-AR) mediates signals resulting in gallbladder contraction. Deteriorating gallbladder contraction promotes gallstone formation. A common genetic polymorphism of CCK-AR may be causatively associated with the risk of gallstone and GBC. This study aimed to understand the association of CCK-AR Pst I polymorphism in gallstone disease with gallbladder cancer.

METHOD

This study included 165 gallstone patients, 139 GBC patients, and 190 healthy subjects. Genotyping was done using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The frequency of the A1A1 genotype of CCK-AR was significantly higher in gallstone patients than healthy individuals (P = 0.008 odds ratio [OR] = 2.25, and 95% confidence interval [CI]:1.2-4.1). However, there was a significant difference in the frequency of A1A1 genotype when gallstone patients were compared to GBC patients (P = 0.041, OR = 0.49, and 95% CI: 0.3-0.9). On stratification of GBC patients according to presence or absence of gallstones, GBC patients without stones were compared to controls and GBC patients with stones were compared to stone patients; however, no significant differences in frequencies were observed.

CONCLUSION

The results suggest that the A1A1 genotype of CCK-AR is an independent genetic risk factor for gallstone disease and does not modulate the susceptibility of gallbladder cancer.

Genetics of biliary tract diseases: new insights into gallstone disease and biliary tract cancers

PURPOSE OF REVIEW

Chronic biliary diseases are due to complex interactions between environmental and genetic factors. Here we summarize the current knowledge of genetic factors that contribute to common biliary diseases, focusing on gallstones and carcinogenesis, and review the recent association studies.

RECENT FINDINGS

Since most studies were based on small sample sizes, replication of the findings is mandatory. Recently a large twin study confirmed a genetic predisposition to gallstones and a genome-wide association scan identified the hepatocanalicular cholesterol transporter ABCG8 as the common susceptibility factor for gallstone disease. Genetic studies in patients with cholangiocarcinoma indicate that genes controlling the metabolism and transport of xenobiotics or modulating chronic inflammation may determine individual susceptibility.

SUMMARY

Genetic studies have identified the first susceptibility factors for gallstones and biliary tract cancers, but most results have yet to be replicated. In the future, genome-wide studies in different populations are likely to identify the entire set of genes contributing to chronic biliary diseases. Since the disease phenotypes result from the manifestation of susceptibility factors under the influence of environmental triggers, the discovery of these genes will open avenues to control environmental challenges and lead to novel strategies for risk assessment ('gene signatures') and prevention.

Role of genetic variant A-204C of cholesterol 7alpha-hydroxylase (CYP7A1) in susceptibility to gallbladder cancer

Gallbladder carcinoma (GBC) usually arises in the background of gallstone disease. Cholesterol 7alpha-hydroxylase (CYP7A1) is a rate-limiting enzyme for cholesterol catabolism and bile acid synthesis. A-204C genetic polymorphism in CYP7A1 may influence gene expression and thus affect the risk of gallstone disease and GBC. We aimed to study the association of A-204C variation of CYP7A1 gene promoter polymorphism in GBC patients, gallstone patients and healthy subjects. The study included 141 histopathologically proven GBC patients, ultrasonographically proven 185 symptomatic gallstone patients and 200 gallstone-free healthy subjects. Genotyping was done by PCR-RFLP method. CYP7A1 A-204C genotypes in control population were in Hardy-Weinberg equilibrium. The CC genotype conferred marginally significant risk for gallstone disease (p=0.051; OR=1.54; 95% CI=0.9-3.4). In GBC patients, the CYP7A1 A-204C polymorphism conferred high risk for GBC at genotype (p=0.005; OR=2.78; 95% CI: 1.3-5.6) as well as allele levels (p=0.008; OR=1.58 and 95% CI: 1.1-2.2). After stratification of GBC patients on the basis of presence or absence of gallstones, CC genotype imparted higher risk for GBC without stones (p=0.002; OR=4.44: 95% CI=1.7-11.3). The association of the polymorphism with GBC was more pronounced in female GBC patients, and also in cancer patients who developed GBC at advanced age. The CC genotype of CYP7A1 is an independent genetic risk factor for GBC but plays a modest role in susceptibility to gallstone disease. The GBC pathogenesis by CYP7A1 polymorphism appears to be independent of gallstone pathway and probably involves genotoxicity due to lipid peroxidation mechanisms.

The risk of gallbladder cancer from polyps in a large multiethnic series

BACKGROUND

The aim of this study is assess whether patients with Indian ethnic background are at an increased risk of developing gallbladder cancer (GBC) if they have been diagnosed with ultrasonic abnormalities of the gallbladder.

METHODS

Between January 1998 and July 2006, 137,655 abdominal ultrasound examinations were performed in Leeds Teaching Hospitals NHS Trust. After the exclusion of repeat scans and those performed for renal or pelvic disease, 71,431 reports were included in this analysis. Patients in whom the diagnosis of GBC has been made without histology have been identified from the database of Northern and Yorkshire Cancer Registry and the presence of GBC was correlated with ultrasonic gallbladder abnormalities.

RESULTS

Gallbladder polyps (GBP) were detected in 3.3% of patients and these were larger than 10 mm in 0.1% of the cases. Age above 60 years, Indian ethnic background, single GBP larger than 10mm, the presence of gallstones, severe gallbladder wall thickening and irregular thickening were independently associated with the higher odds of developing GBC. The prevalence of malignancy in those with GBP was significantly higher among patients with Indian ethnic background compared to Caucasian patients, 5.5% versus 0.08%, p<0.001.

CONCLUSIONS

The presence of GBP, irrelevant of size, amongst patients of Indian ethnic decent, is an indication for further investigation and/or cholecystectomy.

Association of GSTM1, GSTT1, and GSTM3 gene polymorphisms and susceptibility to cervical cancer in a North Indian population

OBJECTIVE

The objective of the study was to evaluate the influence of genetic polymorphisms of GSTM1, GSTT1, and GSTM3 on the susceptibility of cervical cancer.

STUDY DESIGN

Blood samples from 150 women with biopsy-confirmed cervical cancer and 168 healthy controls were analyzed by multiplex polymerase chain reaction (PCR) to detect the presence or absence of GSTM1 and GSTT1. Insertion/deletion polymorphism in intron 6 of GSTM3 was determined by PCR.

RESULTS

The frequencies of homozygous GSTM1 null and GSTT1 null genotypes were found to be significantly higher in cancer patients as compared with healthy controls (P = .009, odds ratio [OR] 1.52, 95% confidence interval [CI], 1.1 to 2.0 and P = .0004, OR 2.4, 95% CI: 1.4 to 4.0, respectively). The AB genotype of GSTM3 also conferred higher risk of cancer (P = .053, OR 1.64, 95% CI, 1.0 to 2.6). However, no significant association of at-risk genotypes was observed with any stages of cervical cancer. Interactions among GSTM1 null, GSTT1 null, and AB genotype of GSTM3 resulted in additive predictive risks of cervical cancer. In case-only analysis, carriers of the AA genotype of GSTM3 among tobacco users were at elevated risk of cervical cancer (P = .024, OR 2.1, 95% CI, 1.0 to 4.1) as compared with AB and BB genotypes.

CONCLUSION

GSTM1 null, GSTT1 null, and GSTM3*AB genotypes may confer higher susceptibility to cervical cancer and cancer risk because at-risk genotypes are additive. Tobacco usage by carriers of GSTM3*AA has enhanced the risk of cervical cancer as compared with nonusers.

Role of GSTM3 polymorphism in the risk of developing esophageal cancer

GSTM3 is involved in detoxification of carcinogens and may be important in modulating cancer susceptibility. GSTM3 genotype frequencies were determined in peripheral blood DNA of 149 esophageal cancer patients and 200 nonmalignant controls using the PCR followed by PAGE. Patients who were heterozygous carriers of GSTM3 AB genotype had an enhanced risk for developing esophageal cancer [odds ratio (OR), 2.1; 95% confidence interval (95% CI), 1.1-3.7; P = 0.01]. In males, the risk due to GSTM3 AB genotype increased further (OR, 3.4; 95% CI, 1.7-6.8; P = 0.000). Interaction of GSTM3 AB + BB and GSTM1 null genotypes marginally modulated risk (OR, 2.3; 95% CI, 1.1-3.7; P = 0.01). Association with histology (adenocarcinoma: OR, 3.4; 95% CI, 1.1-10.9; P = 0.03) and tumor site (middle third location: OR, 2.2; 95% CI, 1.1-4.4; P = 0.01; lower third location: OR, 2.6; 95% CI, 1.2-5.6; P = 0.01) was also documented. Our results suggest that GSTM3 polymorphism may influence esophageal cancer susceptibility, in particular modulating the risk for adenocarcinoma histology and tumors of the mid and lower third region.

Role of BCL2 (ala43thr), CCND1 (G870A) and FAS (A-670G) polymorphisms in modulating the risk of developing esophageal cancer

BACKGROUND

Perturbations in the cell cycle and apoptotic genes have been implicated in human malignancies. A study of BCL2 ala43thr, CCND1 G870A and FAS A-670G gene polymorphisms was undertaken to explore their role in influencing the susceptibility for development of esophageal cancer.

METHODS

A total of 151 patients and age and gender matched 201 controls were investigated for BCL2 ala43thr, CCND1 G870A and FAS A-670G polymorphisms by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP).

RESULTS

The ala43ala genotype of BCL2 anti-apoptotic gene was significantly associated with risk of developing esophageal cancer (OR 2.1, 95%CI=1.0-4.4, P=0.03), more so in males (OR 2.6, 95%CI=P=0.03). In CCND1 G870A polymorphism, the AA genotype was marginally associated with higher risk of esophageal cancer (OR 1.5, 95%CI=0.98-2.4, P=0.05). No significant differences in genotype frequencies of FAS A-670G polymorphism were seen between esophageal cancer patients and controls (P=0.32). Interaction of BCL2 ala43ala, CCND1 870AA and FAS -670AA genotypes did not increase the risk multiplicatively. Association with clinical characteristics showed BCL2 ala43ala genotype to be at increased risk for developing tumors in the middle third location (OR 2.3, 95%CI=1.0-5.3, P=0.03), while patients with CCND1 870AA genotypes were at higher risk for the development of cancer in the upper third location (OR 3.8, 95%CI=1.6-9, P=0.002). BCL2 ala43ala genotype did not modulate the cancer risk in tobacco users. However, patients with CCND1 870AA and FAS -670AA genotypes were associated with a significantly lower number of smoking and chewing pack-years, suggesting a dose-dependent interaction in the risk for esophageal cancer (P=0.005).

CONCLUSION

There appears to be an influence of BCL2 ala43ala and CCND1 870AA genotypes on esophageal cancer phenotype, particularly with regard to tumor location, which supports the theory of prevalence of site-specific genetic alterations. FAS A-670G was not associated with the risk of developing esophageal cancer. Gene-environment interaction analysis showed cancer susceptibility in CCND1 870AA and FAS -670AA genotype to be influenced by quantity of tobacco.

Polymorphisms of cytochrome P450 1A1, glutathione S-transferase class mu, and tumour protein p53 genes and the risk of developing gallbladder cancer in Japanese

OBJECTIVES

To examine the relationship between genetic polymorphisms of cytochrome P450 1A1 (CYP1A1), glutathione S-transferase class mu (GSTM1), and tumour protein p53 (TP53) genes, and gallbladder cancer (GBC) risk, a case-control study was conducted.

DESIGN AND METHODS

Genotypes of CYP1A1 T3801C, CYP1A1 Ile462Val, GSTM1, and TP53 Arg72Pro were determined in 54 cases of GBC and 178 controls.

RESULTS

The age-adjusted odds ratios (ORs) for the Ile/Val genotype of CYP1A1 Ile462Val polymorphism in women and the Arg/Pro genotype of TP53 Arg72Pro polymorphism in men were observed to be 2.70 (95% CI: 1.14-6.40) and 4.32 (95% CI: 1.08-17.2), respectively. No significant differences in the genotypic frequencies of CYP1A1 T3801C and GSTM1 polymorphisms were observed between controls and cases in both men and women.

CONCLUSION

These results suggest that the Val allele of CYP1A1 Ile462Val polymorphism and the Pro allele of TP53 Arg72Pro polymorphism contribute to an increased risk of GBC among Japanese women and men, respectively.