Polymorphisms of glutathione-S-transferases M1, T1, P1 and susceptibility to colorectal cancer in a sample of the Tunisian population

Association of genetic polymorphism of glutathione S-transferases with colorectal cancer susceptibility in snuff (Naswar) addicts

Abstract The current study aimed to investigate the relationship between polymorphisms in detoxifying (GSTM1, GSTT1, and GSTP1) genes and their association with colorectal cancer (CRC) in tobacco addicts of Pashtun ethnicity. Polymorphisms in the selected genes were genotyped in a case-control study consisting of 100 histologically confirmed male CRC patients and 100 birth-year and gender-matched healthy controls using the PCR−RFLP method. The GSTM1 null, and GSTT1 null genotypes were significantly contributed to the risk of CRC in the cases (OR= 3.131, 95% CI: 1.451−6.758, P = 0.004, and OR= 3.541, 95% CI: 1.716−7.306, P = 0.001, respectively), whereas the association observed for GSTP1 Val/Val (1.139, 95% CI: 0.356−3.644, P = 0.826) did not show statistical significance. The combined GSTM1 null and GSTT1 null showed a 41-fold increased risk (95% CI: 4.945−351.950, P = 0.001), while, the combined GSTM1 null and GSTP1 Ile/Val or Val/Val variant genotypes exhibited about 3-fold (95% CI: 1.196−7.414, P = 0.019) increased risk to CRC. Similarly, the combined GSTT1 null and GSTP1 Ile/Val or Val/Val variant genotypes showed about a 3-fold (95% CI: 1.285−8.101, P = 0.013) increased risk of CRC. In the combination of three GST genotypes, the GSTM1 null, GSTT1 null, and GSTP1 Ile/Val or Val/Val variant genotypes demonstrated a more than a 22-fold (95% CI: 2.441−212.106, P = 0.006) increased risk of CRC. Our findings suggest that GSTM1 and GSTT1 polymorphism and its combination with GSTP1 may be associated with CRC susceptibility in the Naswar addicted Pashtun population of Khyber Pakhtunkhwa, Pakistan.

Individual and combined effects of GSTM1 and GSTT1 polymorphisms on colorectal cancer risk: an updated meta-analysis

BACKGROUND

The presence or absence of glutathione S-transferase M1 gene (GSTM1) and glutathione S-transferase T1 gene (GSTT1) polymorphisms, and their combined effects have been suggested as a risk factor for colorectal cancer (CRC). However, the results are inconsistent.

OBJECTIVES

An updated meta-analysis was performed to solve the controversy.

METHODS

Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines were used.

RESULTS

Overall, the GSTM1 null genotype was associated with an increased CRC risk in Caucasians (odds ratio (OR) = 1.14, 95% confidence interval (CI): 1.05-1.23), Asians (OR = 1.19, 95% CI: 1.08-1.32), high-quality studies (OR = 1.12, 95% CI: 1.06-1.18). Moreover, the GSTM1 null genotype was also associated with an increased colon cancer risk (OR = 1.32, 95% CI: 1.16-1.51). The GSTT1 null genotype was also associated with an increased CRC risk in Asians (OR = 1.08, 95% CI: 1.02-1.15) and Caucasians (OR = 1.24, 95% CI: 1.09-1.41). Moreover, The GSTT1 null genotype was associated with an increased rectal cancer risk (OR = 1.13, 95% CI: 1.01-1.27, I2 = 8.3%) in subgroup analysis by tumor location. Last, the GSTM1 null/GSTT1 null genotype was associated with an increased CRC risk in Asians.

CONCLUSION

This meta-analysis indicates that the GSTM1 and GSTT1 null genotypes are associated with increased CRC risk in Asians and Caucasians, and the GSTM1 null/GSTT1 null genotype was associated with increased CRC risk in Asians.

CORRELATION ANALYSIS OF GSTP1 GENE POLYMORPHISM WITH MORBIDITY OF PRIMARY METASTATIC COLORECTAL CANCER

Colorectal cancer (CRC) is one of the most common malignancies. Susceptibility to malignant processes is mediated by genetically driven differences in the effectiveness of detoxification of potential carcinogens. One of the factors that may influence the risk of CRC is the glutathione-S-transferase (GST) gene family that encodes glutathione transferase enzymes. The GSTP1 gene is expressed both in normal and pathological conditions. Determining its specific alleles may be a marker of CRC. The aim of the research – to study GSTP1 gene polymorphism, which is likely to be more common among patients with primary metastatic colorectal cancer compared with healthy population. Materials and methods. The study involved 12 patients with primary metastatic colorectal cancer aged 43 to 72 years, the control group was represented by a sample of 31 people without cancer. Results. The incidence of advanced CRC in the presence of GSPT1 Val / Val (aa) polymorphism is statistically significantly higher than in the presence of Ile / Ile (AA) and Ile / Val (Aa) GSPT1 polymorphism. Conclusions. Among people with GSTP1 Val / Val (aa) polymorphism, primary CRC is 4.4 times more likely than among people with GSPT1 Ile / Ile (AA) and Ile / Val (Aa) polymorphisms, which are statistically significant (P < 0.05). The obtained results indicate the possibility of conducting a genetic study of GSTP1 polymorphism to form groups of potential risk of CRC.

Genetic polymorphism of drug metabolism enzymes (GSTM1, GSTT1 and GSTP1) in the healthy Malian population

Glutathione S-transferase genes, known to be highly polymorphic, are implicated in the process of phase II metabolism of many substrates, including xenobiotics, anticancer and anti-infective drugs. The detoxification activity is linked to individual genetic makeup. Therefore, the identification of alleles and genotypes in these genes within a population may help to better design genetic susceptibility and pharmacogenetic studies. We performed the present study to establish the frequencies of the GSTM1, GSTT1, and GSTP1 c. 313A > G (rs1695) polymorphisms in 206 individuals of the Malian healthy population. GSTM1 and GSTT1 were genotyped by using multiplex polymerase chain reaction, whereas genotypes of GSTP1 were identified by polymerase chain reaction followed by restriction fragment length polymorphism. The frequencies of GSTM1-null and GSTT1-null genotypes were respectively 24.3 and 41.3%. The observed genotype frequencies for GSTP1 were 25.73% homozygous wild-type AA, 49.03% heterozygous AG and 25.24% homozygous mutant GG. The frequency of GSTP1-A allele was 50.24% versus 49.76% for the GSTP1-G allele. The distribution of these three genes was homogeneous between men and women (p > 0.05). We found no statistical association between the presence of a particular profile of GSTM1 or GSTT1 with the genotypes of GSTP1 (p > 0.05). Nevertheless, we noticed that the majority of the individuals harboring the GSTM1-present or the GSTT1-present harbor also the GSTP1-AG genotype. In addition, the triple genotype GSTM1-present/GSTT1-present/AG was the most frequent with 25.2%. Our findings will facilitate future studies regarding genetic associations of multifactorial diseases and pharmacogenetic, thus opening the way to personalized medicine in our population.

Deletion and Single Nucleotide Polymorphisms in Common Glutathione-S Transferases Contribute to Colorectal Cancer Development

Glutathione-S transferases (GSTs) are xenobiotic-conjugation enzymes involved in the detoxification process of heterocyclic aromatic amines and polycyclic aromatic hydrocarbons, widely recognized risk factors of colorectal cancer (CRC) development. Polymorphism in GSTs often leads to alteration or complete lack of enzyme activity, which might have an effect on CRC carcinogenesis. Aim of this study was to investigate GST gene variants as risk factors in patients with CRC. A total of 523 CRC patients administered for surgical resection and 400 matched controls were included. Deletion polymorphism of GSTs M1 and T1 was investigated by polymerase chain reaction. Single nucleotide polymorphism of GST A1 and P1 was investigated by restriction fragment length polymorphism method. The association between GST genotype and risk of CRC development was found in carriers of GSTT1-null and GSTP1-variant genotypes individually (p = 0.050 and p = 0.016, respectively). Furthermore, statistically significant association was found when combination of GSTP1-variant genotype with any of other three common GST genotypes was analyzed with respect to CRC susceptibility. Additionally, patients with combined GSTM1-null/GSTT1-null/GSTA1 low-activity/GSTP1-variant genotype showed 2.71-fold increased risk of developing CRC (p = 0.037). This study supports hypothesis that GST polymorphisms might have an important role in the process of the CRC development. Additionally, GSTM1-null/ GSTT1-null/ GSTA1 low-activity/ GSTP1-variant genotype could be combination of GST genotypes whose carriers are more prone to CRC development.

Molecular evaluation of glutathione S transferase family genes in patients with sporadic colorectal cancer

AIM

To evaluate the association between polymorphisms in glutathione S transferases (GSTs) and the risk of sporadic colorectal cancer (SCRC), tumor progression and the survival of patients.

METHODS

A case-control study of 970 individuals from the Brazilian population was conducted (232 individuals from the case group with colorectal cancer and 738 individuals from the control group without a history of cancer). PCR multiplex and PCR-RFLP techniques were used to genotype the GST polymorphisms. The tumors were categorized according to the TNM classification: tumor extension (T), affected lymph nodes (N), and presence of metastasis (M). Logistic regression, multiple logistic regression and survival analysis were used to analyze the data. The results are presented in terms of odds ratio (OR) and 95% confidence interval (CI). The level of significance was set at 5% (P ≤ 0.05).

RESULTS

Age equal to or over 62 years (OR = 8.79; 95%CI: 5.90-13.09, P < 0.01) and female gender (OR = 2.91; 95%CI: 1.74-4.37; P < 0.01) were associated with increased risk of SCRC. Analysis of the polymorphisms revealed an association between the GSTM1 polymorphisms and a risk of SCRC (OR = 1.45; 95%CI: 1.06-2.00; P = 0.02), as well as between GSTT1 and a reduced risk of the disease (OR = 0.65; 95%CI: 0.43-0.98; P = 0.04). An interaction between the presence of the wild-type allele of GSTP1 Ile105Val polymorphism and tobacco consumption on risk of SCRC (OR = 2.33; 95%CI: 1.34-4.05; P = 0.05) was observed. There was an association between the GSTM1 null genotype and the presence of advanced tumors (OR = 2.33; 95%CI: 1.23-4.41; P = 0.009), as well as increased risk of SCRC in the presence of a combination of GSTT1 non-null/GSTM1 null genotypes (OR = 1.50; 95%CI: 1.03-2.19; P = 0.03) and GSTT1 non-null/GSTM1 null/GSTP1 Val* (OR = 1.85; 95%CI: 1.01-3.36, P = 0.04). Combined GSTT1 non-null/GSTM1 null genotypes (OR = 2.40; 95%CI: 1.19-4.85; P = 0.01) and GSTT1 non-null/GSTM1 null/GSTP1 Val* (OR = 2.92; 95%CI: 1.05-8.12; P = 0.04) were associated with tumor progression. Polymorphisms were not associated with the survival of patients with SCRC.

CONCLUSION

Females aged 62 years or older are more susceptible to SCRC. Polymorphisms of GSTT1 and GSTM1 null genotypes modulated the susceptibility to SCRC in the population studied.

GSTM1, GSTT1, and GSTP1 polymorphisms and colorectal cancer risk in Polish nonsmokers

Glutathione S-transferase (GST) enzymes are responsible for cellular detoxification of many carcinogens and are important anticancer elements. This study assessed potential relationships between GSTM1, GSTT1, and GSTP1 polymorphisms and colorectal cancer (CRC) risk in Polish nonsmokers. We also analyzed the influence of GST gene polymorphisms on CRC clinical and histopathological features. Our study included 197 CRC patients and 104 healthy controls. GSTM1, GSTT1, and GSTP1 polymorphisms were evaluated using qPCR. Polymorphism frequencies observed in our control group corresponded to those in other European populations. The GSTM1 null and GSTT1 null genotypes were observed with similar frequencies in both CRC patients and controls (GSTM1 null: 46.7% vs. 45.2%; GSTT1 null: 15.7% vs. 20.2%). GSTP1 Ile/Ile, Ile/Val, and Val/Val genotype frequencies were respectively 42.1%, 48.2%, and 9.6% in patients and 48.1%, 42.3%, and 9.6% in controls. GSTT1 polymorphism correlated with higher tumor grade in CRC patients, and the GSTM1 null/null genotype was associated with more frequent metastasis to lymph nodes (pN classification). Our results suggest that GST gene polymorphisms may influence CRC tumor grade and stage.

Glutathione-S-Transferase Deletions and Non-arteritic Anterior Ischemic Optic Neuropathy

In this study, we aimed at investigating the association between glutathione-S-transferase (GSTM1 and GSTT1) deletion genotypes and susceptibility to non-arteritic anterior ischemic optic neuropathy (NAION). We hope our findings may contribute to the understanding NAION pathogenesis and provide some clues for the prevention and treatment of optic diseases. The NAION group contains 113 subjects (33 males and 80 females, mean age 55.3 ± 9.8). And 98 subjects were enrolled in the control group (32 males and 66 females, mean age 56.7 ± 10.2). The individuals involved in the study were matched by gender and age to obtain two homogenous groups. GSTM1- and GSTT1- genotype and the combined genotype were investigated. The genotype distributions in NAION patients were compared with those in the controls. Significantly altered intraocular pressure (IOP) and cup-to-disc ratio (CDR) was detected between NAION patients and controls. An increased risk of NAION was observed among individuals with GSTM1- (P < 0.001). No significant difference was confirmed for GSTT1- (P = 0.290). Individuals with GSTM1-/GSTT1- have a higher susceptibility to NAION (P < 0.001); the GSTM1-/GSTT1+ genotype also had a significantly higher frequency in patients than in controls (P = 0.004). But the genotype of GSTM1+/GSTT1- seems to have no connection with NAION (P = 0.476). In conclusion, in this study, we confirmed the connection between NAION and GSTM1- genotype. But no significant association was observed between GSTT1- genotype and NAION susceptibility. In further analysis regarding combined genotype, a trend of protective effect was detected for GSTT1+ genotype. It is indicated by our result that oxidative compounds might play an important part in the pathogenesis of NAION.