GSTP1

Gene Summary

Gene:GSTP1; glutathione S-transferase pi 1
Aliases: PI, DFN7, GST3, GSTP, FAEES3, HEL-S-22
Location:11q13.2
Summary:Glutathione S-transferases (GSTs) are a family of enzymes that play an important role in detoxification by catalyzing the conjugation of many hydrophobic and electrophilic compounds with reduced glutathione. Based on their biochemical, immunologic, and structural properties, the soluble GSTs are categorized into 4 main classes: alpha, mu, pi, and theta. This GST family member is a polymorphic gene encoding active, functionally different GSTP1 variant proteins that are thought to function in xenobiotic metabolism and play a role in susceptibility to cancer, and other diseases. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:glutathione S-transferase P
Source:NCBIAccessed: 09 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 09 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 09 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: GSTP1 (cancer-related)

Kumar U, Sharma U, Rathi G
Reversal of hypermethylation and reactivation of glutathione S-transferase pi 1 gene by curcumin in breast cancer cell line.
Tumour Biol. 2017; 39(2):1010428317692258 [PubMed] Related Publications
One of the mechanisms for epigenetic silencing of tumor suppressor genes is hypermethylation of cytosine residue at CpG islands at their promoter region that contributes to malignant progression of tumor. Therefore, activation of tumor suppressor genes that have been silenced by promoter methylation is considered to be very attractive molecular target for cancer therapy. Epigenetic silencing of glutathione S-transferase pi 1, a tumor suppressor gene, is involved in various types of cancers including breast cancer. Epigenetic silencing of tumor suppressor genes can be reversed by several molecules including natural compounds such as polyphenols that can act as a hypomethylating agent. Curcumin has been found to specifically target various tumor suppressor genes and alter their expression. To check the effect of curcumin on the methylation pattern of glutathione S-transferase pi 1 gene in MCF-7 breast cancer cell line in dose-dependent manner. To check the reversal of methylation pattern of hypermethylated glutathione S-transferase pi 1, MCF-7 breast cancer cell line was treated with different concentrations of curcumin for different time periods. DNA and proteins of treated and untreated cell lines were isolated, and methylation status of the promoter region of glutathione S-transferase pi 1 was analyzed using methylation-specific polymerase chain reaction assay, and expression of this gene was analyzed by immunoblotting using specific antibodies against glutathione S-transferase pi 1. A very low and a nontoxic concentration (10 µM) of curcumin treatment was able to reverse the hypermethylation and led to reactivation of glutathione S-transferase pi 1 protein expression in MCF-7 cells after 72 h of treatment, although the IC50 value of curcumin was found to be at 20 µM. However, curcumin less than 3 µM of curcumin could not alter the promoter methylation pattern of glutathione S-transferase pi 1. Treatment of breast cancer MCF-7 cells with curcumin causes complete reversal of glutathione S-transferase pi 1 promoter hypermethylation and leads to re-expression of glutathione S-transferase pi 1, suggesting it to be an excellent nontoxic hypomethylating agent.

Negovan A, Iancu M, Moldovan V, et al.
The Interaction between GSTT1, GSTM1, and GSTP1 Ile105Val Gene Polymorphisms and Environmental Risk Factors in Premalignant Gastric Lesions Risk.
Biomed Res Int. 2017; 2017:7365080 [PubMed] Free Access to Full Article Related Publications
The study investigated the possible influence of GSTM1, GSTT1, and GSTP1 gene polymorphisms as predisposing factors for premalignant gastric lesions as well as their interaction with H. pylori infection, gastrotoxic drugs, smoking, and alcohol consumption. In this study, 270 patients with a complet set of gastric biopsies and successfully genotyped were finally included. The GSTM1 gene polymorphism had significant contribution in mild/severe endoscopic lesions (p = 0.01) as well as in premalignant lesions (p = 0.01). The GSTM1 null genotype increased the risk for mucosal defects in H. pylori-negative patients (OR = 2.27, 95% CI: 1.20-4.37) and the risk for premalignant lesions in patients with no alcohol consumption (OR = 2.13, 95% CI: 1.19-3.83). The GSTT1 deleted polymorphism did not significantly increase the risk for premalignant lesions in the absence of gastrotoxic drugs (OR = 1.82, 95% CI: 0.72-4.74). The combined GSTT1T1 and GSTM1 null polymorphisms were borderline correlated with an increased risk for premalignant lesions (OR = 1.72, 95% CI: 1.00-2.97). The wild-type GSTP1 Ile/Ile genotype versus the variant genotypes Ile/Val + Val/Val was significantly associated with a decreased risk of gastric atrophy/intestinal metaplasia (OR = 0.60, 95% CI: 0.37-0.98). In conclusion, the GSTM1 and GSTT1 null genotypes increased the risk for premalignant and endoscopic gastric lesions, modulated by H. pylori, alcohol, or gastrotoxic drug consumption, while the presence of the GSTP1Val allele seemed to reduce the risk for premalignant lesions.

Liu HX, Li J, Ye BG
Correlation between gene polymorphisms of CYP1A1, GSTP1, ERCC2, XRCC1, and XRCC3 and susceptibility to lung cancer.
Genet Mol Res. 2016; 15(4) [PubMed] Related Publications
Lung cancer is a common malignant tumor that is characterized by high morbidity and poor prognosis. Studies suggest that an individual's genetic background affects the risk of developing lung cancer. Therefore, we investigated the relationship between gene polymorphisms and susceptibility to lung cancer. We recruited 308 primary lung cancer patients as subjects and 253 healthy adults as controls. After extraction of DNA from blood samples, gene polymorphisms in CYP1A1, GSTP1, ERCC2, XRCC1, and XRCC3 were investigated by polymerase chain reaction and restriction fragment length polymorphism. The frequencies of the genotypes in both groups were investigated to obtain odds ratios and 95% confidence intervals, and correlation analysis was carried out. The analysis results showed that the following polymorphisms were correlated with susceptibility to lung cancer: rs4646903 in CYP1A1 (P < 0.001), rs1048943 in CYP1A1 (P < 0.001), rs1695 in GSTP1 (P < 0.05), rs13181 in ERCC2 (P < 0.001), and rs25487 in XRCC1 (P < 0.05); no such correlation existed in rs861539 in XRCC3 (P > 0.05). The study revealed that the more high-risk gene polymorphisms a patient carries, the greater the risk of developing lung cancer. Carriers of rs4646903 in CYP1A1, rs1048943 in CYP1A1, rs1695 in GSTP1, rs13181 in ERCC2, and rs25487 in XRCC1 are more likely to develop lung cancer.

Drozd E, Krzysztoń-Russjan J, Marczewska J, et al.
Up-regulation of glutathione-related genes, enzyme activities and transport proteins in human cervical cancer cells treated with doxorubicin.
Biomed Pharmacother. 2016; 83:397-406 [PubMed] Related Publications
Doxorubicin (DOX), one of the most effective anticancer drugs, acts in a variety of ways including DNA damage, enzyme inhibition and generation of reactive oxygen species. Glutathione (GSH) and glutathione-related enzymes including: glutathione peroxidase (GPX), glutathione reductase (GSR) and glutathione S-transferases (GST) may play a role in adaptive detoxification processes in response to the oxidative stress, thus contributing to drug resistance phenotype. In this study, we investigated effects of DOX treatment on expression and activity of GSH-related enzymes and multidrug resistance-associated proteins in cultured human cervical cancer cells displaying different resistance against this drug (HeLa and KB-V1). Determination of expression level of genes encoding GST isoforms and MRP proteins (GCS, GPX, GSR, GSTA1-3, GSTM1, GSTP1, ABCC1-3, MGST1-3) was performed using StellARray™ Technology. Enzymatic activities of GPX and GSR were measured using biochemical methods. Expression of MRP1 was examined by immunofluorescence microscopy. This study showed that native expression levels of GSTM1 and GSTA3 were markedly higher in KB-V1 cells (2000-fold and 200-fold) compared to HeLa cells. Resistant cells have also shown significantly elevated expression of GSTA1 and GSTA2 genes (200-fold and 50-fold) as a result of DOX treatment. In HeLa cells, exposure to DOX increased expression of all genes: GSTM1 (7-fold) and GSTA1-3 (550-fold, 150-fold and 300-fold). Exposure to DOX led to the slight increase of GCS expression as well as GPX activity in KB-V1 cells, while in HeLa cells it did not. Expression of ABCC1 (MRP1) was not increased in any of the tested cell lines. Our results indicate that expression of GSTM1 and GSTA1-3 genes is up-regulated by DOX treatment and suggest that activity of these genes may be associated with drug resistance of the tested cells. At the same time, involvement of MRP1 in DOX resistance in the given experimental conditions is unlikely.

Jia W, Sun JY, Jia KY, Liu XC
Role of GSTM1, GSTT1, and GSTP1 IIe105Val gene polymorphisms in the response to chemotherapy and overall survival of advanced non-small cell lung cancer.
Genet Mol Res. 2016; 15(3) [PubMed] Related Publications
We evaluated the association between GSTM1, GSTT1, and GSTP1 IIe105Val gene polymorphisms and treatment outcomes of advanced non-small cell lung carcinoma. Between January 2010 and December 2012, a total of 244 patients with non-small cell lung carcinoma were recruited from Yiwu Central Hospital. The GSTM1, GSTT1, and GSTP1 IIe105Val gene polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism and the results were statistically analyzed. Conditional regression analysis, showed that individuals carrying the null GSTM1 were associated with an increased risk of response to chemotherapy when compared to the present GSTM1 (odds ratio = 1.88, 95% confidence interval (CI) = 1.01-3.47). Moreover, the GG genotype of GSTP1 IIe105Val was associated with a better response to chemotherapy compared to the AA genotype (odds ratio = 2.77, 95%CI = 1.14-6.64). The null GSTM1 genotype was associated with a lower risk of death from all causes when compared with the present GSTM1 genotype (hazard ratio = 2.16, 95%CI = 1.10-4.38). Moreover, the GG genotype of GSTP1 IIe105Val was correlated with a reduced risk of death from all causes compared with the AA genotype (hazard ratio = 2.94, 95%CI = 1.11-8.68). In conclusion, we found that the null GSTM1 and the GG genotype of GSTP1 IIe105Val were correlated with a good response to chemotherapy and improved overall survival of advanced non-small cell lung carcinoma patients.

Yu Y, Li X, Liang C, et al.
The relationship between GSTA1, GSTM1, GSTP1, and GSTT1 genetic polymorphisms and bladder cancer susceptibility: A meta-analysis.
Medicine (Baltimore). 2016; 95(37):e4900 [PubMed] Related Publications
BACKGROUND: Previous studies have investigated the relationship between GSTA1, GSTM1, GSTP1, and GSTT1 polymorphisms and bladder cancer (BCa) susceptibility, respectively, but the results remain inconsistent. So, we conducted this meta-analysis including 79 case-control studies to explore such relationships.
METHODS: We searched PubMed, EMBASE, Cochrane library, Web of Science, and CNKI for relevant available studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were implemented to evaluate the intensity of associations. Publication bias was estimated using Begg funnel plots and Egger regression test. To assess the stability of the results, we used sensitivity analysis with the method of calculating the results again by omitting 1 single study each time. Between-study heterogeneity was tested using the I statistic.
RESULTS: No significant association between GSTA1 polymorphism and BCa susceptibility (OR = 1.05, 95% CI 0.83-1.33) was noted. Besides, meaningful association between individuals who carried the GSTM1 null genotype and increased BCa risk was detected (OR = 1.39, 95%CI 1.28-1.51). When stratified by ethnicity, significant difference was found in both Caucasian (OR = 1.39, 95% CI 1.23-1.58) and Asian populations (OR = 1.45, 95% CI 1.31-1.61). Moreover, in the subgroup analysis by source of controls (SOC), the results were significant in both hospital-based control groups (OR = 1.49, 95% CI 1.35-1.64) and population-based control groups (OR = 1.21, 95% CI = 1.07-1.37). Additionally, the analysis revealed no significant association between GSTP1 polymorphism and BCa risk (OR = 1.07, 95% CI 0.96-1.20). What is more, significant associations between GSTT1 polymorphism and BCa susceptibility were discovered (OR = 1.11, 95% CI 1.00-1.22). In the subgroup analysis by ethnicity, significant associations between GSTT1 null genotype and BCa risk were observed only in Caucasians (OR = 1.25, 95% CI 1.09-1.44). Furthermore, when stratified by SOC, no obvious relationship was found between the GSTT1 null genotype polymorphism with hospital-based population (OR = 1.11, 95% CI 0.97-1.28) or population-based population (OR = 1.10, 95% CI 0.96-1.27).
CONCLUSION: This study suggested that GSTM1 null genotype and GSTT1 null genotype might be related to higher BCa risk, respectively. However, no associations were observed between GSTA1 or GSTP1 polymorphisms and BCa susceptibility.

Martignano F, Gurioli G, Salvi S, et al.
GSTP1 Methylation and Protein Expression in Prostate Cancer: Diagnostic Implications.
Dis Markers. 2016; 2016:4358292 [PubMed] Free Access to Full Article Related Publications
GSTP1 belongs to the GSTs family, a group of enzymes involved in detoxification of exogenous substances and it also plays an important role in cell cycle regulation. Its dysregulation correlates with a large variety of tumors, in particular with prostate cancer. We investigated GSTP1 methylation status with methylation specific PCR (MS-PCR) in prostate cancer (PCa) and in benign tissue of 56 prostatectomies. We also performed immunohistochemistry (IHC) so as to correlate gene methylation with gene silencing. GSTP1 appears methylated in PCa and not in healthy tissue; IHC confirmed that methylation leads to protein underexpression (p < 0.001). GSTP1 is highly expressed in basal cell layer and luminal cells in benign glands while in prostatic intraepithelial neoplasia (PIN) it stains only basal cell layer, whereas PCa glands are completely negative. We demonstrated that methylation leads to underexpression of GSTP1. The progressive loss of GSTP1 expression from healthy glands to PIN and to PCa glands underlines its involvement in early carcinogenesis.

Yan F, Wang R, Geng L
The 341C/T polymorphism in the GSTP1 gene and lung cancer risk: a meta-analysis.
Genet Mol Res. 2016; 15(3) [PubMed] Related Publications
Numerous studies have evaluated the association between the 341C/T polymorphism in glutathione S-transferase P1 (GSTP1) and lung cancer risk. However, there are conflicting results from previous studies. To derive a more precise estimation of the association, we conducted this meta-analysis. A comprehensive search was conducted to identify the eligible studies examining the GSTP1 341C/T polymorphism and lung cancer risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. The meta-analysis results showed that the GSTP1 341C/T polymorphism was significantly associated with lung cancer risk (TT vs CC: OR = 3.33, 95%CI = 1.49-7.44; CT vs CC: OR = 1.35, 95%CI = 1.10-1.65; dominant model: OR = 1.43, 95%CI = 1.05-1.96; recessive model: OR = 0.31, 95%CI = 0.14-0.70). The results indicate that the GSTP1 341C/T polymorphism may contribute to lung cancer risk. Conclusive evidence on the effects of this variant in lung cancer should be addressed in further studies.

Minciu R, Dumache R, Gheorghe P, et al.
Molecular Diagnostic of Prostate Cancer From Body Fluids Using Methylation-Specific PCR (MS-PCR) Method.
Clin Lab. 2016; 62(6):1183-6 [PubMed] Related Publications
BACKGROUND: Worldwide prostate cancer (PCa) represents the 2nd leading cause of cancer related deaths among men. Currently, the screening for early detection of PCa is based on determination of serum prostate-specific antigen (PSA) levels. But this biomarker presents some disadvantages related to its specificity and sensitivity. In our study, we want to determine if methylation levels of the glutathione S-transferase P1 (GSTP1) gene could be used as a new biomarker for the early detection of PCa and to distinguish between malignant and benign pros-tatic lesions.
METHODS: To determine the methylation levels of the GSTP1 gene, 31 men with histopathological diagnosis of prostate adenocarcinoma and 34 men with the histopathological diagnosis of benign prostatic hyperplasia (BPH) as controls were included in the study group. The genomic DNA was extracted from urine samples. We analyzed the methylation levels of the GSTP1 gene by methylation-specific polymerase chain reaction (MS-PCR) method.
RESULTS: In prostate cancer patients 27 of 31 (87%) presented hypermethylated levels of the GSTP1 gene, whereas 4 of 34 (11.8%) BPH patients had hypermethylated levels of the GSTP1 gene. Further, in the case of these four patients a second biopsy was done, which confirmed the diagnosis of prostate adenocarcinoma. Using the receiver operating curve (ROC), we obtained a specificity of 87% and a sensitivity of 98% for the GSTP1 gene.
CONCLUSIONS: We can conclude that GSTP1 represents a new molecular biomarker which can aid in early detection of PCa and be used to discriminate between benign and malignant prostatic lesions from body fluids by noninvasive methods.

Bu L, Zhang LB, Mao X, Wang P
GSTP1 Ile105Val and XRCC1 Arg399Gln gene polymorphisms contribute to the clinical outcome of patients with advanced non-small cell lung cancer.
Genet Mol Res. 2016; 15(2) [PubMed] Related Publications
Glutathione S-transferase P1 (GSTP1) and X-ray repair cross-complementing group 1 (XRCC1) genetic variations may in-fluence the efficacy of chemotherapy in various cancers. We investi-gated the possible roles of GSTP1 Ile105Val and XRCC1 Arg194Trp, and Arg399Gln gene polymorphisms in the prognosis of advanced non-small cell lung carcinoma (NSCLC) patients with cisplatin-based chemotherapy. Between January 2010 and December 2012, this study consecutively recruited 141 patients with advanced NSCLC from the First People's Hospital of Yunnan Province. Logistic regression analy-sis showed that individuals carrying the GG genotype were associated with a better response to chemotherapy than those with the wide-type genotype, with an adjusted odds ratio (95% confidence interval, CI) of 4.07 (1.06-25.06). Moreover, we observed that the AA genotype of XRCC1 Arg399Gln was correlated with a greater complete response + partial response to chemotherapy than that with the GG genotype (odds ratio = 2.71, 95%CI = 1.13-10.08). Based on the Cox hazard proportional model, the GG genotype of GSTP1 Ile105Val was found to be associated with a lower risk of death from all causes as compared to that with the AA genotype (hazard ratio = 0.07, 95%CI = 0.01-0.34). In summary, we suggest that GSTP1 Ile105Val and XRCC1 Arg399Gln polymorphisms could influence the response to chemotherapy and sur-vival of advanced NSCLC.

Abo-Hashem EM, El-Emshaty WM, Farag Rel S, et al.
Genetic Polymorphisms of Cytochrome P4501A1 (CYP1A1) and Glutathione S-Transferase P1 (GSTP1) and Risk of Hepatocellular Carcinoma Among Chronic Hepatitis C Patients in Egypt.
Biochem Genet. 2016; 54(5):696-713 [PubMed] Related Publications
Cytochrome P450 1A1 (CYP1A1) and Glutathione S-transferase P1 (GSTP1) genes are involved in the metabolism of many carcinogens. Polymorphisms in these genes with altered enzyme activity have been reported. The present study evaluated the synergistic effect between CYP1A1 and GSTP1 gene polymorphisms and smoking on development of HCV-related liver disease and hepatocellular carcinoma (HCC). The patients group comprised 40 patients with HCC and 40 patients with liver cirrhosis. The control group comprised 40 healthy subjects having no history of malignancy. The genetic polymorphisms were studied using polymerase chain reaction restriction fragment length polymorphism (PCR RFLP) technique on blood samples. The number of current or former smoker among HCC and cirrhotic patients as well as the median Pack/year of cigarette smoked were significantly higher in HCC and liver cirrhotic patients than in control group. Subjects with CYP1A1 gene variants (m1 and m3) had no significant risk to develop cirrhosis or HCC compared to control group. Individuals carrying the Ile/Val genotype of GSTP1 had a significant increased risk of HCC (OR of 2.2, 95 % CI 1.143-4.261) and had larger tumor size. No significant risk was observed on combining both genes variants or on combining smoking with variants of both genes. In conclusion, the GSTP1 Ile/Val genotype and Val allele are associated with an increased risk of HCC. CYP1A1 and GSTP1 genes variants interaction did not increase the risk of HCC.

Xiao HL, Yang ZT, Han F, Wei HX
Association of glutathione S-transferase (GST) genetic polymorphisms with treatment outcome of cisplatin-based chemotherapy for advanced non-small cell lung cancer in a Chinese population.
Genet Mol Res. 2016; 15(2) [PubMed] Related Publications
The aim of this study was to evaluate the association of GSTM1 null/present, GSTT1 null/present, and GSTP1 IIe105Val polymorphisms with the chemotherapy response and overall survival of advanced NSCLC. Two hundred and sixty-two patients with histologically confirmed advanced NSCLC (inoperable TNM stages IIIA, IIIB, and IV) were enrolled to this hospital-based study between May 2009 and May 2012. The GSTM1 null/present, GSTT1 null/present, and GSTP1 IIe105Val polymorphisms were genotyped by polymerase chain reaction coupled with restriction fragment length polymorphism. A logistic regression analysis revealed a correlation between the null genotype of GSTM1 and improved response to chemotherapy [odds ratio = 1.82; 95% confidence interval (CI) = 1.06-3.14]. Analyses with the Cox proportional hazards model also indicated that the null genotype of GSTM1 was associated with lower risk of death (hazard ratio = 0.40; 95%CI = 0.23-0.69). In conclusion, the null genotype of GSTM1 was found to be correlated with improved response to chemotherapy and lower risk of death in advanced NSCLC patients.

Shen X, Wang J, Yan X, et al.
Predictive value of GSTP1 Ile105Val polymorphism in clinical outcomes of chemotherapy in gastric and colorectal cancers: a systematic review and meta-analysis.
Cancer Chemother Pharmacol. 2016; 77(6):1285-302 [PubMed] Related Publications
PURPOSE: Gastric and colorectal cancers remain the major causes of cancer-related death with a bad prognosis. Up to now, platinum combined with fluoropyrimidines has been most commonly used in chemotherapy regimens of gastric and colorectal cancers. Recently, a series of studies have been conducted to investigate the associations of biomarkers, such as GSTP1 Ile105Val polymorphism, with the chemotherapy efficacy in gastric and colorectal cancers; however, the results were not consistent and inconclusive. Here, we performed a systematic review and meta-analysis to summarize the associations of GSTP1 Ile105Val polymorphism with the chemotherapy efficacy in gastric and colorectal cancers.
METHODS: A systematic review was conducted to search relevant studies in English databases (PubMed, ISI Web of Science, and EMBASE) up to November 30, 2015. The pooling ORs or HRs were used to assess the strength of the associations of GSTP1 Ile105Val polymorphism with clinical outcomes such as tumor response, toxicity, progression-free survival (PFS), and overall survival (OS).
RESULTS: Forty-one papers containing 8169 cases were finally included in the present meta-analysis study. Of which, 28 articles were performed in colorectal cancers, one in gastrointestinal carcinoma (gastric and colon cancer), 11 in gastric cancers, and one in colorectal and gastroesophageal cancers. After pooling all the eligible studies, we identified significant associations of GSTP1 Ile105Val polymorphism with chemotherapy-related tumor response (G vs. A: OR 1.697, 95 % CI 1.191-2.418; GG vs. AA: OR 2.804, 95 % CI 1.414-5.560; AG vs. AA: OR 1.540, 95 % CI 1.011-2.347; GG vs. AAAG: OR 2.139, 95 % CI 1.256-3.641), PFS (GG vs. AA, HR 0.640, 95 % CI 0.455-0.900; AGGG vs. AA: HR 0.718, 95 % CI 0.562-0.919), and OS (AG vs. AA: HR 0.857, 95 % CI 0.746-0.986; GG vs. AA: HR 0.679, 95 % CI 0.523-0.882; AGGG vs. AA: HR 0.663, 95 % CI 0.542-0.812) in gastric and colorectal cancers and no significant association was found between the polymorphism with toxicity.
CONCLUSIONS: GSTP1 Ile105Val polymorphism was associated with tumor response, PFS, and OS in gastric and colorectal cancers after chemotherapy.

Ghatak S, Yadav RP, Lalrohlui F, et al.
Xenobiotic Pathway Gene Polymorphisms Associated with Gastric Cancer in High Risk Mizo-Mongoloid Population, Northeast India.
Helicobacter. 2016; 21(6):523-535 [PubMed] Related Publications
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.

Khabaz MN, Al-Maghrabi JA, Nedjadi T, et al.
Does Val/Val genotype of GSTP1 enzyme affects susceptibility to colorectal cancer in Saudi Arabia?.
Neuro Endocrinol Lett. 2016; 37(1):46-52 [PubMed] Related Publications
OBJECTIVES: Glutathione S-transferase pi (GSTP1) is a candidate enzyme that may be involved in colorectal cancer susceptibility. Polymorphism of GSTP1 gene may cause changes in expression or structure which lead to alteration in the efficiency of catalytic function of the enzyme variants, i.e., deficient detoxification of carcinogens and consequently influences coloreActal cancer development. The present report examined the possible impact of GSTP1 (Ilel05Val) polymorphism and the risk of colorectal cancer.
METHODS: Samples of paraffin embedded tissues from 83 patients with colorectal cancer as well as thirty five non-cancerous colon tissues were collected from the archive of the pathology department at King Abdulaziz University in Saudi Arabia. All cancer and control samples were subjects to DNA extraction then amplification. DNA genetic analyzer from Applied Biosystems was used to sequence the product of amplification for genotypes determination.
RESULTS: None of the genotypes of GSTP1 was associated with the risk of colorectal cancer development. There were no statistical differences in the frequencies of GSTP1 genotypes between colorectal cancer cases and controls.
CONCLUSION: The incidence of (Val/Val) genotype in colorectal cancer cases was three folds higher than controls. This finding is not statistically significant, but it could be of clinical consequence that it may increase the risk of colorectal cancer in Saudi Arabia.

Nasr AS, Sami RM, Ibrahim NY, Darwish DO
Glutathione S transferase (GSTP 1, GSTM 1, and GSTT 1) gene polymorphisms in Egyptian patients with acute myeloid leukemia.
Indian J Cancer. 2015 Oct-Dec; 52(4):490-5 [PubMed] Related Publications
BACKGROUND: The super family of glutathione S-transferases (GSTs) is composed of multiple isoenzymes with significant evidence of functional polymorphic variation. GSTs detoxify potentially mutagenic and toxic DNA-reactive electrophiles, including metabolites of several chemotherapeutic agents, some of which are suspected human carcinogens. Polymorphisms within the phase II metabolizer enzymes GST T1, GST M1, and GST P1 affect the body's ability to detoxify a range of potential leukemogens encountered in the environment.
AIM OF WORK: To address how differences in the human GST isoenzyme expression patterns influence cancer susceptibility, prognosis, and treatment.
PATIENTS AND METHODS: A total of 50 patients with acute myeloid leukemia (AML), as well as 50 age and sex matched apparently healthy volunteers were genotyped for GSTP 1, GSTM 1, and GSTT 1 gene polymorphisms using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and conventional polymerase chain reaction (PCR), respectively.
RESULTS: For GSTP1 313 A → G (GSTP1 Ile105Val) polymorphism, It was found that the wild genotype (AA) was significantly higher among control subjects (P value = 0.0277), while the frequency of heteromutant genotype (AG) and mutant G allele (AG + GG) was significantly higher among patients (P value = 0.0402, P value = 0.0277, respectively). For GSTM1 and GSTT1gene, we found statistically significantly higher frequency among patients regarding homozygous gene deletion (P value = 0.0005).
CONCLUSION: We demonstrated that GSTM1 null or GSTT1 null genotypes may be considered independent risk factors for AML with no impact on prognosis and GSTP1 * 105 genotype is a prognostic factor, adding independent information to the routine laboratory parameters and cytogenetic and molecular alterations of the tumor cells.

Grasso C, Trevisan M, Fiano V, et al.
Performance of Different Analytical Software Packages in Quantification of DNA Methylation by Pyrosequencing.
PLoS One. 2016; 11(3):e0150483 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Pyrosequencing has emerged as an alternative method of nucleic acid sequencing, well suited for many applications which aim to characterize single nucleotide polymorphisms, mutations, microbial types and CpG methylation in the target DNA. The commercially available pyrosequencing systems can harbor two different types of software which allow analysis in AQ or CpG mode, respectively, both widely employed for DNA methylation analysis.
OBJECTIVE: Aim of the study was to assess the performance for DNA methylation analysis at CpG sites of the two pyrosequencing software which allow analysis in AQ or CpG mode, respectively. Despite CpG mode having been specifically generated for CpG methylation quantification, many investigations on this topic have been carried out with AQ mode. As proof of equivalent performance of the two software for this type of analysis is not available, the focus of this paper was to evaluate if the two modes currently used for CpG methylation assessment by pyrosequencing may give overlapping results.
METHODS: We compared the performance of the two software in quantifying DNA methylation in the promoter of selected genes (GSTP1, MGMT, LINE-1) by testing two case series which include DNA from paraffin embedded prostate cancer tissues (PC study, N = 36) and DNA from blood fractions of healthy people (DD study, N = 28), respectively.
RESULTS: We found discrepancy in the two pyrosequencing software-based quality assignment of DNA methylation assays. Compared to the software for analysis in the AQ mode, less permissive criteria are supported by the Pyro Q-CpG software, which enables analysis in CpG mode. CpG mode warns the operators about potential unsatisfactory performance of the assay and ensures a more accurate quantitative evaluation of DNA methylation at CpG sites.
CONCLUSION: The implementation of CpG mode is strongly advisable in order to improve the reliability of the methylation analysis results achievable by pyrosequencing.

Campbell JM, Bateman E, Peters MDj, et al.
Fluoropyrimidine and platinum toxicity pharmacogenetics: an umbrella review of systematic reviews and meta-analyses.
Pharmacogenomics. 2016; 17(4):435-51 [PubMed] Related Publications
Fluoropyrimidine (FU) and platinum-based chemotherapies are greatly complicated by their associated toxicities. This umbrella systematic review synthesized all systematic reviews that investigated associations between germline variations and toxicity, with the aim of informing personalized medicine. Systematic reviews are important in pharmacogenetics where false positives are common. Four systematic reviews were identified for FU-induced toxicity and three for platinum. Polymorphisms of DPYD and TYMS, but not MTHFR, were statistically significantly associated with FU-induced toxicity (although only DPYD had clinical significance). For platinum, GSTP1 was found to not be associated with toxicity. This umbrella systematic review has synthesized the best available evidence on the pharmacogenetics of FU and platinum toxicity. It provides a useful reference for clinicians and identifies important research gaps.

Yamada N, Yasui K, Dohi O, et al.
Genome-wide DNA methylation analysis in hepatocellular carcinoma.
Oncol Rep. 2016; 35(4):2228-36 [PubMed] Related Publications
Epigenetic changes as well as genetic changes are mechanisms of tumorigenesis. We aimed to identify novel genes that are silenced by DNA hypermethylation in hepatocellular carcinoma (HCC). We screened for genes with promoter DNA hypermethylation using a genome-wide methylation microarray analysis in primary HCC (the discovery set). The microarray analysis revealed that there were 2,670 CpG sites that significantly differed in regards to the methylation level between the tumor and non-tumor liver tissues; 875 were significantly hypermethylated and 1,795 were significantly hypomethylated in the HCC tumors compared to the non‑tumor tissues. Further analyses using methylation-specific PCR, combined with expression analysis, in the validation set of primary HCC showed that, in addition to three known tumor-suppressor genes (APC, CDKN2A, and GSTP1), eight genes (AKR1B1, GRASP, MAP9, NXPE3, RSPH9, SPINT2, STEAP4, and ZNF154) were significantly hypermethylated and downregulated in the HCC tumors compared to the non-tumor liver tissues. Our results suggest that epigenetic silencing of these genes may be associated with HCC.

Bănescu C, Iancu M, Trifa AP, et al.
From Six Gene Polymorphisms of the Antioxidant System, Only GPX Pro198Leu and GSTP1 Ile105Val Modulate the Risk of Acute Myeloid Leukemia.
Oxid Med Cell Longev. 2016; 2016:2536705 [PubMed] Free Access to Full Article Related Publications
Oxidative stress might contribute to the occurrence of cancers, including the hematological ones. Various genetic polymorphisms were shown to increase the quantity of reactive oxygen species, a phenomenon that is able to induce mutations and thus promote cancers. The purpose of the study was to evaluate the association between CAT C262T, GPX1 Pro198Leu, MnSOD Ala16Val, GSTM1, GSTT1, and GSTP1 Ile105Val gene polymorphisms and acute myeloid leukemia risk, in a case-control study comprising 102 patients and 303 controls. No association was observed between AML and variant genotypes of CAT, MnSOD, GSTM1, and GSTT1 polymorphisms. Our data revealed a statistically significant difference regarding the frequencies of GPX1 Pro198Leu and GSTP1 Ile105Val variant genotypes between AML patients and controls (p < 0.001). Our results showed no association in the distribution of any of the CAT C262T, GPX1 Pro198Leu, GSTM1, GSTT1, and GSTP1 polymorphisms regarding age, gender, FAB subtype, cytogenetic risk groups, FLT3 and DNMT3 gene mutations, and overall survival. Our data suggests that the presence of variant allele and genotype of GPX1 Pro198Leu and GSTP1 Ile105Val gene polymorphisms may modulate the risk of developing AML.

Zhao R, Chen G
Role of GSTP1 Ile105Val and XRCC1 Arg194Trp, Arg280His and Arg399Gln gene polymorphisms in the clinical outcome of advanced non-small cell lung cancer.
Int J Clin Exp Pathol. 2015; 8(11):14909-16 [PubMed] Free Access to Full Article Related Publications
We conducted a study to investigate the association between the clinical outcome and GSTP1 Ile105Val and XRCC1 Arg194Trp, Arg280His and Arg399Gln gene polymorphisms in advanced NSCLC patients with cisplatin-based chemotherapy. Between January 2010 and December 2012, a total of 206 patients with advanced NSCLC were histopathologically confirmed were included into analysis. By logistic regression analysis, individuals carrying the AG and GG genotypes of GSTP1 Ile105Val were associated with better response to chemotherapy when compared with the AA genotype, and the adjusted Ors (95% CI) were 2.06 (1.10-3.86) and 4.89 (1.52-18.33), respectively. The TT genotype of XRCC1 Arg194Trp was correlated with better response to chemotherapy compared to the CC genotype, and the adjusted OR (95% CI) was 3.23 (1.20-9.30). By Cox Hazard Proportional Model, the GG genotype of GSTP1 Ile105Val and the TT genotype of XRCC1 Arg194Trp were found to be associated with lower risk of death from all causes when compared with the wide-type genotype, and the adjusted HRs (95% CI) were 0.05 (0.01-0.18) and 0.20 (0.07-0.62), respectively. Moreover, individuals carrying both the G/A+G/G genotype of GSTP1 Ile105Val and the G/A+A/A of XRCC1 Arg194Trp were associated with heavy greater CR+PR response to chemotherapy (OR=2.98, 95% CI=1.39-6.42), and also correlated with longer overall survival of advanced NSCLC (HR=0.19, 95% CI=0.05-0.61). In conclusion, we found that the GSTP1 Ile105Val and XRCC1 Arg194Trp were associated with better response to chemotherapy and longer survival of advanced NSCLC, compared to the wide-type genotype.

Ghosh S, Ghosh S, Bankura B, et al.
Association of DNA repair and xenobiotic pathway gene polymorphisms with genetic susceptibility to gastric cancer patients in West Bengal, India.
Tumour Biol. 2016; 37(7):9139-49 [PubMed] Related Publications
Gastric cancer is one of the most common malignancies in India. DNA repair gene or xenobiotic pathway gene polymorphisms have recently been shown to affect individual susceptibility to gastric cancer. Here, the possible interaction between common polymorphisms in X-ray repair cross complementing group I (XRCC1) gene and glutathione S-transferase (GST) genes (GSTM1, GSTT1 and GSTP1), smoking and alcohol consumption and overall survival in gastric cancer patients were evaluated. In this population-based case control study, 70 gastric cancer patients and 82 healthy controls were enrolled. The epidemiological data were collected by a standard questionnaire, and blood samples were collected from each individual. XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphisms were determined by polymerase chain reaction and direct DNA sequencing. GSTM1 and GSTT1 null polymorphisms and GSTP1 Ile105Val polymorphism were identified by multiplex polymerase chain reaction and restriction fragment length polymorphism (RFLP), respectively. The risk of gastric cancer was significantly elevated in individuals with XRCC1 Arg/Gln +Gln/Gln (p = 0.031; odds ratio = 2.32; 95 % confidence interval (CI) 1.07-5.06) and GSTP1 Val/Val genotype (p = 0.009; odds ratio = 8.64; 95 % CI 1.84-40.55). An elevated risk for GC was observed in smokers and alcohol consumers carrying GSTP1 Ile/Val +Val/Val genotype (p = 0.041; odds ratio = 3.71; 95 % CI 0.98-14.12; p = 0.002; odds ratio = 12.31; 95 % CI 1.71-88.59). These findings suggest that XRCC1 rs25487 and GSTP1 rs1695 can be considered as a risk factor associated with gastric cancer and might be used as a molecular marker for evaluating the susceptibility of the disease.

Shinozuka K, Tang H, Jones RB, et al.
Impact of Polymorphic Variations of Gemcitabine Metabolism, DNA Damage Repair, and Drug-Resistance Genes on the Effect of High-Dose Chemotherapy for Relapsed or Refractory Lymphoid Malignancies.
Biol Blood Marrow Transplant. 2016; 22(5):843-9 [PubMed] Related Publications
The goal of this study was to determine whether single nucleotide polymorphisms (SNPs) in genes involved in gemcitabine metabolism, DNA damage repair, multidrug resistance, and alkylator detoxification influence the clinical outcome of patients with refractory/relapsed lymphoid malignancies receiving high-dose gemcitabine/busulfan/melphalan (Gem/Bu/Mel) with autologous stem cell support. We evaluated 21 germline SNPs of the gemcitabine metabolism genes CDA, deoxycytidine kinase, and hCNT3; DNA damage repair genes RECQL, X-ray repair complementing 1, RAD54L, ATM, ATR, MLH1, MSH2, MSH3, TREX1, EXO1, and TP73; and multidrug-resistance genes MRP2 and MRP5; as well as glutathione-S-transferase GSTP1 in 153 patients with relapsed or refractory lymphoma or myeloma receiving Gem/Bu/Mel. We studied the association of genotypes with overall survival (OS), progression-free survival (PFS), and nonhematological grade 3 or 4 toxicity. CDA C111T and TREX1 Ex14-460C>T genotypes had a significant effect on OS (P = .007 and P = .005, respectively), and CDA C111T, ATR C340T, and EXO1 P757L genotypes were significant predictors for severe toxicity (P = .037, P = .024, and P = .025, respectively) in multivariable models that adjusted for clinical variables. The multi-SNP risk score analysis identified the combined genotypes of TREX1 Ex14-460 TT and hCNT3 Ex5 +25A>G AA as significant predictors for OS and the combination of MRP2 Ex10 + 40GG/GA and MLH1 IVS12-169 TT as significant predictor for PFS. Polymorphic variants of certain genes involved in gemcitabine metabolism and DNA damage repair pathways may be potential biomarkers for clinical outcome in patients with refractory/relapsed lymphoid tumors receiving Gem/Bu/Mel.

Wu G, Jiang B, Liu X, et al.
Association of GSTs gene polymorphisms with treatment outcome of advanced non-small cell lung cancer patients with cisplatin-based chemotherapy.
Int J Clin Exp Pathol. 2015; 8(10):13346-52 [PubMed] Free Access to Full Article Related Publications
We evaluated the association of GSTM1 null/present, GSTT1 null/present, and GSTP1 IIe105Val polymorphisms with the clinical response to chemotherapy and treatment outcome of NSCLC. Between October 2009 and October 2012, a total of 282 patients with advanced NSCLC were enrolled into our study, and they were followed up until October 2014. The genotypes of GSTM1, GSTT1, and GSTP1 IIe105Val were performed by polymerase chain reaction (PCR) coupled with restriction fragment length polymorphism (RFLP). By logistic regression analysis, our study found that the Val/Val genotype of GSTP1 IIe105Val was associated with more CR+PR response to chemotherapy when compared with the IIe/IIe genotype, and the OR (95% CI) was 2.18 (1.16-4.12). By multivariate Cox proportional hazards regression analysis, we found the Val/Val genotype of GSTP1 was correlated with lower risk of death in advanced NSCLC (HR, 0.48; 95% CI, 0.25-0.93). However, no association was found between GSTT1 and GSTM1 polymorphisms and response to chemotherapy and overall survival of advanced NSCLC. Moreover, the IIe/Val + Val/Val genotypes of GSTP1 were associated with lower risk of death in never smokers, and the adjusted HR (95% CI) was 0.34 (0.12-0.93). In conclusion, we found that the GSTP1 polymorphism was correlated with better response to chemotherapy and lower risk of death in advanced NSCLC patients.

Zmorzyński S, Świderska-Kołacz G, Koczkodaj D, Filip AA
Significance of Polymorphisms and Expression of Enzyme-Encoding Genes Related to Glutathione in Hematopoietic Cancers and Solid Tumors.
Biomed Res Int. 2015; 2015:853573 [PubMed] Free Access to Full Article Related Publications
Antioxidant compounds such as glutathione and its enzymes have become the focus of attention of medical sciences. Glutathione, a specific tripeptide, is involved in many intercellular processes. The glutathione concentration is determined by the number of GAG repeats in gamma-glutamylcysteine synthetase. GAG polymorphisms are associated with an increased risk of schizophrenia, berylliosis, diabetes, lung cancer, and nasopharyngeal tumors. Cancer cells with high glutathione concentration are resistant to chemotherapy treatment. The oxidized form of glutathione is formed by glutathione peroxidases (GPXs). The changes in activity of GPX1, GPX2, and GPX3 isoforms may be associated with the development of cancers, for example, prostate cancer or even colon cancer. Detoxification of glutathione conjugates is possible due to activity of glutathione S-transferases (GSTs). Polymorphisms in GSTM1, GSTP1, and GSTO1 enzymes increase the risk of developing breast cancer and hepatocellular carcinoma. Gamma-glutamyl transpeptidases (GGTs) are responsible for glutathione degradation. Increased activity of GGT correlates with adverse prognosis in patients with breast cancer. Studies on genes encoding glutathione enzymes are continued in order to determine the correlation between DNA polymorphisms in cancer patients.

Yuan P, Yuan L, Xu BL, et al.
Predictive potential role of glutathione S-transferases polymorphisms in response to chemotherapy and breast cancer prognosis.
Genet Mol Res. 2015; 14(4):16675-81 [PubMed] Related Publications
The aim of this study was to evaluate the role of GSTM1 null/present, GSTT1 null/present, and GSTP1 polymorphisms in the clinical response to chemotherapy and treatment outcome of breast cancer. The GSTM1, GSTT1, and GSTP1 IIe105Val polymorphism genotypes were analyzed using polymerase chain reaction coupled with restriction fragment length polymorphism. Conditional logistic regression analysis revealed that breast cancer patients carrying the GG genotype of GSTP1 IIe105Val showed a significantly better response to chemotherapy compared to those expressing the AA genotype [odds ratio = 2.66, 95% confidence interval (CI) = 1.24-5.91, P = 0.007]. The Cox proportional hazards model indicated that the GG genotype of GSTP1 IIe105Val in breast cancer patients was correlated with a lower risk of death from all causes than those with AA genotype. The adjusted hazard ratio (95%CI) for the GG genotype of GSTP1 IIe105Val was 0.44 (0.18-0.99; P = 0.03). In conclusion, the results of our study indicated that the GG genotype of GSTP1 IIe105Val was significantly associated with better response to chemotherapy and longer overall survival, compared to the wide-type genotype.

Di Francia R, De Lucia L, Di Paolo M, et al.
Rational selection of predictive pharmacogenomics test for the Fluoropyrimidine/Oxaliplatin based therapy.
Eur Rev Med Pharmacol Sci. 2015; 19(22):4443-54 [PubMed] Related Publications
OBJECTIVE: Both Fluoropyrimidine and Oxaliplatin (FluOx) are the most common anticancer drugs used to treat colorectal, ovarian, and gastrointestinal cancers. Nevertheless, the efficacy of FluOx-based therapy is often compromised by the severe risk of neurotoxicity, cardiotoxicity, and gastrointestinal toxicity. Stratification of patients for their individual response to drugs is a promising approach for cancer treatment and cost-effectiveness. Here we evaluate the most recent findings on the most appropriate gene variants related to the toxicity in patients receiving FluOx chemotherapy.
MATERIALS AND METHODS: A systematic literature search of the MEDLINE, EMBASE, and Cochrane databases was conducted to identify all clinical studies of any association between DPYD and 5-FU correlated to allelic status of 6 validated polymorphisms in five genes Dihydropyrimidine Dehydrogenase (DPYD), Thymidylate Synthase (TYMS), Glutathione S-Transferase (GSTP1), and DNA-repair genes (ERCC2 and XRCC1).
RESULTS: The stratification of the patients into three genotype profiles group, who are most likely responders to FluOx treatments, provide informations about toxicity and/or resistance before starting therapy. Also, early evaluation cost of panel testing proposed is averaged about €100,00 per sample. The evaluation costs of genotyping before starting treatment could be a good cost-effectiveness strategy.
CONCLUSIONS: Based on the individual genomic profile, the oncologists will have new possibilities, based on the individual genetic profile, to make treatment decisions for their patients and to redefine scheduling and dosage of FluOx-based therapy.

Fang C, Wei XM, Zeng XT, et al.
Aberrant GSTP1 promoter methylation is associated with increased risk and advanced stage of breast cancer: a meta-analysis of 19 case-control studies.
BMC Cancer. 2015; 15:920 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Glutathione S-transferase P1 (GSTP1) has been reported to function as a tumor suppressor gene in various types of human cancers. Aberrant methylation of tumor-related genes at the promoter regions can inactivate genes, which is important in the carcinogenesis of breast cancer. However, the role of GSTP1 promoter methylation in the occurrence of breast cancer and its relationship with tumor stage and histological grade has not been fully elucidated. Thus, we carried out a meta-analysis to yield a more accurate association.
METHODS: A systematically literature search was made on PubMed, EMBASE and Web of Science databases for eligible studies. The odds ratio (OR) and 95 % confidence interval (95 % CI) were calculated by RevMan 5.2 software. Subgroup and sensitivity analyses were conducted to explore the source of heterogeneity.
RESULTS: Eventually, 17 articles involving 19 case-control studies were included in the present meta-analysis. Overall, the pooled results indicated that aberrant GSTP1 promoter methylation was significantly associated with the risk of breast cancer (OR = 7.85, 95 % CI = 5.12-12.01; Caucasians OR = 7.23, 95 % CI = 3.76-13.90 and Asians OR = 11.71, 95 % CI = 5.69-24.07). Furthermore, our results revealed that GSTP1 promoter methylation was more often observed in late-stage breast cancer patients compared with early-stage ones (OR = 1.84, 95 % CI = 1.32-2.58). However, no significant association was identified between GSTP1 promoter methylation and histological grade (OR = 0.74, 95 % CI = 0.43-1.26).
CONCLUSIONS: The results indicated that GSTP1 promoter methylation probably plays an important role in breast carcinogenesis, which could serve as an effective biomarker for the diagnosis and monitor of breast cancer.

Stavrinou P, Mavrogiorgou MC, Polyzoidis K, et al.
Expression Profile of Genes Related to Drug Metabolism in Human Brain Tumors.
PLoS One. 2015; 10(11):e0143285 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Endogenous and exogenous compounds as well as carcinogens are metabolized and detoxified by phase I and II enzymes, the activity of which could be crucial to the inactivation and hence susceptibility to carcinogenic factors. The expression of these enzymes in human brain tumor tissue has not been investigated sufficiently. We studied the association between tumor pathology and the expression profile of seven phase I and II drug metabolizing genes (CYP1A1, CYP1B1, ALDH3A1, AOX1, GSTP1, GSTT1 and GSTM3) and some of their proteins.
METHODS: Using qRT-PCR and western blotting analysis the gene and protein expression in a cohort of 77 tumors were investigated. The major tumor subtypes were meningioma, astrocytoma and brain metastases, -the later all adenocarcinomas from a lung primary.
RESULTS: Meningeal tumors showed higher expression levels for AOX1, CYP1B1, GSTM3 and GSTP1. For AOX1, GSTM and GSTP1 this could be verified on a protein level as well. A negative correlation between the WHO degree of malignancy and the strength of expression was identified on both transcriptional and translational level for AOX1, GSTM3 and GSTP1, although the results could have been biased by the prevalence of meningiomas and glioblastomas in the inevitably bipolar distribution of the WHO grades. A correlation between the gene expression and the protein product was observed for AOX1, GSTP1 and GSTM3 in astrocytomas.
CONCLUSIONS: The various CNS tumors show different patterns of drug metabolizing gene expression. Our results suggest that the most important factor governing the expression of these enzymes is the histological subtype and to a far lesser extent the degree of malignancy itself.

Abbas M, Kushwaha VS, Srivastava K, Banerjee M
Glutathione S-Transferase Gene Polymorphisms and Treatment Outcome in Cervical Cancer Patients under Concomitant Chemoradiation.
PLoS One. 2015; 10(11):e0142501 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Cisplatin based concomitant chemoradiation (CRT) is the standard treatment for locally advanced cervical cancer (CC). Glutathione S-transferase (GST), a phase II antioxidant enzyme is induced by oxidative stress generated by drugs and reactive oxidants. The present study was undertaken to evaluate the association of GSTM1, T1 and P1 polymorphisms with the outcome of CRT treatment in CC patients.
METHODS: A total of 227 cervical cancer patients with stages IIB-IIIB treated with the same chemoradiotherapy regimen were enrolled and genotyped for GSTM1, T1 and P1 gene polymorphisms by multiplex polymerase chain reaction (mPCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Overall survival was evaluated using Kaplan-Meier survival function and Cox proportional hazards model. All data were analyzed using SPSS (version 21.0).
RESULTS: Stratified analysis showed that GSTM1 null (M1-) genotype was associated with a significantly better survival among patients with stage IIB cervical cancer (log-rank P = 0.004) than cases with stage IIIA/IIIB. Death and recurrence were significantly higher in patients with GSTM1 present genotype (M1+) (P = 0.037 and P = 0.003 respectively) and those with M1- showed reduced hazard of death with an adjusted hazard ratio 'HR' of 0.47 (95% CI, 0.269-0.802, P = 0.006). Women with M1- genotype as well as in combination with GSTT1 null (T1-), GSTP1 (AG+GG) and GSTT1 null/GSTP1 (AG+GG) showed better survival and also reduced risk of death (HR = 0.31, P = 0.016; HR = 0.45, P = 0.013; HR = 0.31, P = 0.02 respectively).
CONCLUSIONS: To the best of our knowledge, this is the first study to correlate the association of GSTM1, T1 and P1 gene polymorphisms with treatment outcome of CRT treated CC patients. Our results suggested that individuals with GSTM1 null genotype and in combination with GSTT1 null and GSTP1 (AG+GG) had a survival advantage. Such genetic studies may provide prognostic information in CRT treated CC patients.

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