Polymorphic variation in glutathione-S-transferase genes and risk of chronic myeloid leukaemia in the Kashmiri population

Association Between the Individual and Combined Effects of the GSTM1 and GSTT1 Polymorphisms and Risk of Leukemia: A Meta-Analysis

Background: Fourteen meta-analyses reported the individual effects of the GSTM1 and GSTT1 polymorphisms on leukemia risk. However, over 40 studies were not included in previously published meta-analyses. Moreover, one key aspect was that previous meta-analyses did not conduct the false-positive test on the aforementioned issues. Furthermore, previous meta-analyses did not observe the combined effects of GSTM1 present/null and GSTT1 present/null polymorphism with leukemia risk. Therefore, we conducted the current study to further analyze these associations.

Objectives: This study aimed to investigate the association between the individual and combined effects of the GSTM1 present/null and GSTT1 present/null polymorphisms and the risk of leukemia.

Methods: A meta-analysis was performed applying Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines. Moreover, false-positive report probability (FPRP) and Bayesian false discovery probability (BFDP) were applied to investigate the false-positive results.

Results: The individual GSTM1 and GSTT1 null genotypes and combined effects of the two genes were associated with a significantly increased leukemia risk in overall and several subgroup analyses, such as Asians, Caucasians, and so on. Then, further analysis was conducted using FPRP and BFDP. Significant associations were considered as “positive” results on the GSTM1 null genotype with leukemia risk in overall populations (FPRP < 0.001 and BFDP = 0.006), Asians (FPRP < 0.001 and BFDP < 0.001), and East Asian population (FPRP < 0.001 and BFDP = 0.002). For the GSTT1 null genotype, significant associations were regarded “positive” results in overall populations, acute myeloid leukemia (AML), Asians, and East Asian population. For the combined effects of the GSTM1 and GSTT1 polymorphisms, significant associations were also considered “positive” results in the overall analysis of Asians, Indians, and East Asian population.

Conclusion: This study strongly indicates that the individual GSTM1 and GSTT1 null genotypes and combined effects of the two genes are associated with increased leukemia risk in Asians, especially in the East Asian population; the GSTT1 null genotype is associated with increased AML risk; the combined effects of the two genes are associated with increased leukemia risk in Indians.

Influence of cytochrome P450 and glutathione S transferase polymorphisms on response to nilotinib therapy among chronic myeloidleukemia patients from Pakistan

Background

Cytochrome P450 (CYP) and glutathione S transferases (GSTs) are important biotransforming enzymes responsible for detoxification of anticancer drugs and carcinogens. Polymorphisms in these enzymes may greatly influence the susceptibility to CML and overall efficacy of tyrosine kinase inhibitors. This study was aimed to estimate the possible influence of the polymorphisms of GSTs and CYP in the occurrence of CML as well as in predicting therapeutic outcome of nilotinib therapy in Pakistani CML patients.

Methods

The polymorphic variability in CYP 1A1*2C, GSTP1 (A3131G), GSTT1 and GSTM1 was assessed either by RFLP or multiplex PCR. The BCR ABL1 transcripts were quantified by qPCR to monitor response to nilotinib.

Results

The CYP1A1*2C heterozygous and GSTP1 homozygous polymorphisms seemed to be a contributing factor in developing CML. Altogether, there were 12 non-responders, 66 responders and 21 partial responders. The most frequent genotype was null GSTM1 in responders followed by CYP 1A1 and GSTP1 -wild type (p =  < 0.05). Whereas, homozygous GSTP1 and GSTT1 null genotype is significantly higher only among nilotinib non-responders.

Conclusion

Hence, it can be concluded that wild type CYP1A1, GSTP1 and null GSTM1 may be frequently linked to favorable outcome in patients treated with nilotinib as depicted by sustained deep molecular response in most CML patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09605-1.

Acute exposure to traffic-related air pollution alters antioxidant status in healthy adults

BACKGROUND

Exposure to traffic-related air pollution is associated with an increased risk of cardiovascular and respiratory disease. Evidence suggests that inhaled pollutants precipitate these effects via multiple pathways involving oxidative stress.

OBJECTIVE

Postulating that a decrease in circulating antioxidant levels reflect an oxidative response, we investigated the effect of inhaled diesel exhaust (DE) on the ratio of reduced to oxidized glutathione (GSH/GSSG) in healthy adults, and whether pre-exposure antioxidant supplementation blunted this response. We also examined exposure-related changes in antioxidant/stress response leukocyte gene expression (GCLc, HMOX-1, IL-6, TGFβ) and plasma IL-6 levels.

METHODS

Nineteen nonsmoking adults participated in a double-blind, randomized, four-way crossover study. Each subject completed 120-min exposures to filtered air and DE (200 μg/m3), with and without antioxidant pretreatment. Antioxidant comprised 1000 mg ascorbate for 7 days and 1200 mg N-acetylcysteine 1 day prior to exposure, with 1000 mg and 600 mg, respectively, administered 2 h prior to exposure. Whole blood glutathione was measured pre- and post-exposure; plasma IL-6 and mRNA expression were quantified pre, during and post exposure.

RESULTS

Diesel exhaust exposure was associated with significantly decreased GSH/GSSG (p = 0.001) and a 4-fold increase in IL-6 mRNA (p = 0.01) post exposure. Antioxidant pretreatment did not significantly mediate the effect of DE exposure on GSH/GSSG, though appeared to decrease the effect of exposure on IL-6 mRNA expression.

CONCLUSIONS

Acute DE inhalation induced detectable oxidative effects in healthy adults, which were not significantly attenuated by the selected antioxidant pre-treatment. This finding supports the premise that oxidative stress is one mechanism underlying the adverse effects of traffic-related air pollution.

Genetic Polymorphism of GSTP1, GSTM1 and GSTT1 Genes and Susceptibility to Chronic Myeloid Leukaemia

BACKGROUND

The development of cancer results from an imbalance between exposure to carcinogens and the capacity of various enzyme systems engaged in activation or in the detoxification of xenobiotics. The aim of the present study is to investigate the association of GSTP1, GSTM1 and GSTT1 gene polymorphisms in susceptibility to Chronic Myeloid Leukaemia (CML).

METHODS

A total of 200 CML patients and 100 controls were enrolled in a case-control study with GSTM1 and GSTT1 analysis with PCR and GSTP1 analysis with PCR-RFLP.

RESULTS

The GSTT1 null genotype was significantly higher among CML patients suggesting that this genotype is associated with an increased risk of CML. It was found in 42% of cases as compared with 21% of the controls, (OR =2.78, 95% CI: 1.59 - 4.85; p-value =0.000). The presence of the GSTT1 genotype may thus be considered a protective factor for CML. The frequency of individuals carrying GSTM1 null genotype was slightly higher in the control group but this difference was not statistically significant. The GSTM1 null genotype was present in 35% of control cases and 34% of the CML patients, (OR=0.975, 95%CI: 0.58-1.58;p-value=0.863). Individuals with a combined GSTM1 null/GSTT1null genotype had an estimated 2.85-fold increased risk of CML, but no associated risk between GSTP1 Ile 105 Val polymorphism and CML was found (OR=1.99, 95% CI: 0.40 - 9.32; p-value = 0.417).

CONCLUSIONS

No association between GSTP1 and GSTM1 with susceptibility to CML was found. GSTT1 genotype may be a protective factor for CML, while the null genotype shows association with developing CML.<br />.

Influence of glutathione S-transferases (GSTM1, GSTT1, and GSTP1) genetic polymorphisms and smoking on susceptibility risk of chronic myeloid leukemia and treatment response

Background

Glutathione S‐transferases (GSTs) polymorphisms may impact on chronic myeloid leukemia (CML) risk or heterogeneous responses to Imatinib mesylate (IM). The aim of this study was to evaluate the correlation between GSTs polymorphisms and CML risk, treatment response.

Methods

We genotyped GSTM1, GSTT1 null deletion polymorphisms, and GSTP1 Ile105Val polymorphism by PCR methods and BCR‐ABL transcripts were analyzed by qRT‐PCR in 104 CML patients and 104 sex‐ and age‐matched healthy individuals.

Results

Individual analysis showed significant association of GSTM1 (p = 0.008; OR = 0.46; 95% CI: 0.26–0.82) and GSTP1 genes (p = 0.04; OR = 1.56; 95% CI: 1.016–2.423) with CML risk. The combined analysis indicated that GSTM1 null/GSTT1 present, GSTM1‐null/GSTP1M*(AG/GG) as well as GSTT1 present/ GSTP1M* genotype were associated with CML risk (ORg(‐):2.28; 95% CI: 1.29–4.04; ORgg: 2.85; 95% CI: 1.36–5.97; OR(‐)g: 1.75; 95% CI: 0.99–3.06, respectively). The proportion of CML cancer attributable to the interaction of smoking and GSTM1 null, GSTT1null, and GSTP1 M* was 42%, 39%, and 13%, respectively. Patients with GSTM1‐null and GSTP1 AG/GG genotype had significantly a lower rate of MMR achievement (p = 0.00; p = 0.009 respectively). Event‐free survival (EFS) percentage was similar between GSTM1 null and GSTM1 present patients (p = 0.21).

Conclusion

Our study suggests the influence of GSTM1 and GSTP1 polymorphisms on CML risk and treatment response. The interaction between GSTs polymorphisms and smoking plays a significant role on CML susceptibility.

Age- and gender-independent association of glutathione S-transferase null polymorphisms with chronic myeloid leukemia

The glutathione S-transferase (GST) genes encode enzymes that mediate the detoxification of xenobiotics by catalyzing the conjugation of glutathione (GSH) to xenobiotic substrates. The aim of the current study is to investigate the association between GSTT1 and GSTM1 polymorphisms and chronic myeloid leukemia (CML) among Sudanese patients. Patients with CML (n = 115) were recruited to the study from the Radiation and Isotope Centre Khartoum (RICK)-Sudan. Healthy individuals (n = 104) were included as controls. Genotyping of GSTT1 and GSTM1 polymorphisms was performed using multiplex PCR. Null deletions in the GSTT1 and GSTM1 genes are common in the Sudanese population (control group), with frequencies of 33.9% and 38.2%, respectively. The frequencies of GSTT1 (OR: 3.25, 95% CI: 1.87-5.65, p < 0.001) and GSTM1 (OR: 2.14, 95% CI: 1.25-3.67, p < 0.005) null genotypes were significantly higher in CML patients vs. controls. The distribution of GSTT1 and GSTM1 null polymorphisms was not different between male and female (p > 0.01) and young and old CML patients (p > 0.05). Hematological parameters were not affected by null polymorphisms in the patient group (p > 0.05). In addition, the frequency of GSTM1 null polymorphism was lower in advanced-phase CML patients compared to chronic-phase patients (p < 0.05). The GSTT1 and GSTM1 null polymorphisms are associated with CML among Sudanese patients, independently of their age and gender.

Genetic Polymorphisms Associated with Environmental Exposure to Polycyclic Derivatives in African Children

Background

The nonracial leukopenia may be a result of exposure to polycyclic derivatives (benzene-toluene-xylene (BTX)) and may arise from a possible change in the bone marrow microenvironment. The present study sought to evaluate the association of genetic polymorphisms in xenobiotic-metabolizing enzymes with hematological and biochemical profiles.

Methods

We evaluated 89 African descendant children, exposed indirectly to benzene derivatives. Laboratory parameters were investigated by automated methods and genetic polymorphisms by PCR-RFLP and PCR multiplex.

Results

Children with leukopenia had significantly decreased white blood cells (WBCs) and platelet counts, which is not consistent with benign leukopenia. In the same group, we have found that carriers of the CYP2E1 variant allele had decreased WBC and lymphocytes. Those with NQO1 variant allele had decreased WBC, neutrophil, eosinophil, monocyte, and lymphocyte counts. Carriers of the MPO variant allele had decreased WBC, neutrophil, eosinophil, basophil, monocyte, lymphocyte, and platelet counts and an elevated free iron level. Children with GSTT and GSTM null exhibited decreased WBC, neutrophil, basophil, and lymphocyte counts. Our multivariate analysis model reveals that females were independently associated with leukopenia.

Conclusion

Our results suggest that the polymorphisms investigated were associated with hematological changes in the studied population. These alterations could be heightened by exposure to benzene derivatives.

Association between polymorphism of GSTP1, GSTT1, GSTM1 and CYP2E1 genes and susceptibility to benzene-induced hematotoxicity

Occupational exposure to benzene has been associated with leukemia, anemia, leukopenia, and thrombocytopenia. Genetic susceptibility to benzene toxicity in humans may be related to variations in benzene metabolizing genes. The main objective of this study was to ascertain whether polymorphism of GSTP1, GSTM1, GSTT1 and CYP2E1 genes might influence susceptibility to the adverse effects of benzene among employees of a petrochemical plant. In this cross-sectional study, 124 employees of a petrochemical plant who had been occupationally exposed to benzene and had one or more abnormal hematological parameter (cases) and 184 subjects with a similar exposure scenario, free from any abnormal hematological parameters (referent) were studied. Atmospheric concentrations of benzene were measured and GSTM1 and GSTT1 genotypes were evaluated using the multiplex polymerase chain reaction (PCR) technique. Additionally, GSTP1 and CYP2E1 genotypes were determined by PCR- restriction fragment length polymorphism (PCR–RFLP). The frequency of null GSTT1 genotype in cases was significantly higher than that of referent group (32.3 vs. 18.5%, OR 2.1, 95% CI 1.23–3.56, p = 0.004). The mean value of platelets in subjects with null GSTT1 genotype was significantly lower than that of individuals with positive GSTT1 genotype (p = 0.015). Conversely, the mean value of leukocytes was significantly higher in subjects with null GSTM1 genotype as compared to those with positive GSTM1 genotype (p = 0.026). Logistic regression analysis showed that, subjects with null GSTT1 genotype had a significantly higher risk for hematological disorders, as compared to those with positive GSTT1 genotype (OR 2.1, 95% CI 1.23–3.56). Moreover, subjects with both null GSTT1 and GSTM1 genotypes had a significantly higher risk for hematological disorders as compared to subjects with positive GSTT1 and GSTM1 genotypes (OR 2.35, 95% CI 1.14–4.8). The results of this study showed that, individuals carrying null GSTT1 or both null STT1 and GSTM1 genotypes had a higher risk and were more susceptible to benzene-induced hematological disorders.

CYP1A1 and GSTP1 gene variations in breast cancer: a systematic review and case-control study

In first part of this study, a systematic review was designed to explore the involvement of CYP1A1 and GSTP1 genes in breast cancerogenesis. Based on systematic review, we designed a study to screen CYP1A1 and GSTP1 genes for mutation and their possible association with breast carcinogenesis. A total of 400 individuals were collected and analyzed by PCR-SSCP. After sequence analysis of coding region of CYP1A1 we identified eleven mutations in different exons of respective gene. Among these eleven mutations, ~3 folds increased breast cancer risk was found associated with Asp82Glu mutation (OR 2.99; 95% CI 1.26-7.09), with Ser83Thr mutation (OR 2.99; 95% CI 1.26-7.09) and with Glu86Ala mutation (OR 3.18; 95% CI 1.27-7.93) in cancer patients compared to controls. Furthermore, ~4 folds increase in breast cancer risk was found associated with Asp347Glu, Phe398Tyr and 5178delT mutations (OR 3.92; 95% CI 1.35-11.3) in patients compared to controls. The sequence analysis of GSTP1 resulted in identification of total five mutations. Among these five mutations, ~3 folds increase in breast cancer risk was observed associated with 1860G>A mutation, with 1861-1876delCAGCCCTCTGGAGTGG mutation (OR 2.70; 95% CI 1.10-6.62) and with 1861C>A mutation (OR 2.97; 95% CI 1.01-8.45) in cancer patients compared to controls. Furthermore, ~5 folds increase in breast cancer risk was associated with 1883G>T mutation (OR 4.75; 95% CI 1.46-15.3) and ~6 folds increase in breast cancer risk was found associated with Iso105Val mutation (OR 6.43; 95% CI 1.41-29.3) in cancer patients compared to controls. Our finding, based on systematic review and experimental data suggest that the polymorphic CYP1A1 and GSTP1 genes may contribute to risk of developing breast cancer.

Chronic Myeloid Leukemia--Prognostic Value of Mutations

Chronic myeloid leukemia (CML) is a stem cell disorder characterized by unrestricted proliferation of the myeloid series that occurs due to the BCR-ABL fusion oncogene as a result of reciprocal translocation t(9;22) (q34;q11). This discovery has made this particular domain a target for future efforts to cure CML. Imatinib revolutionized the treatment options for CML and gave encouraging results both in case of safety as well as tolerability profile as compared to agents such as hydroxyurea or busulfan given before Imatinib. However, about 2-4% of patients show resistance and mutations have been found to be one of the reasons for its development. European Leukemianet gives recommendations for BCR-ABL mutational analysis along with other tyrosine kinase inhibitors (TKIs) that should be administered according to the mutations harbored in a patient. The following overview gives recommendations for monitoring patients on the basis of their mutational status.

GSTM1 and GSTP1, but not GSTT1 genetic polymorphisms are associated with chronic myeloid leukemia risk and treatment response

BACKGROUND

Chronic myeloid leukemia (CML) is associated to the BCR-ABL1 oncogene and can successfully be treated with tyrosine kinase inhibitors (TKIs). However, it remains still under investigation which molecular factors may influence CML risk or varying responses to TKIs. The aim of this study was to assess the role of Glutathione-S-transferases (GSTs) genetic polymorphisms in CML susceptibility and TKI clinical outcome.

MATERIALS

Deletion polymorphisms in GSTM1 and GSTT1 genes and the single nucleotide polymorphism in GSTP1 c.319A>G (rs1695; p.105Ile>Val) were genotyped by PCR methods in 141 CML treated patients and 141 sex- and age-matched healthy individuals.

RESULTS

Individual analysis of each GST gene showed no association with CML risk. A trend toward significance (p=0.07) for a recessive model was found for GSTP1 (OR: 2.04; CI: 0.94-4.4). However, the combined analysis showed that GSTM1-null/GSTP1-GG as well as GSTT1-null/GSTP1-GG were associated with CML development (p=0.03; OR: 3.54 CI: 1.2-14.57; p=0.05; OR: 12.65; CI: 1.17-21.5). The relationship with treatment outcome showed that the presence of GSTM1 gene was significantly linked with an inferior rate of major molecular response (p=0.048) and poor event free-survival (EFS) (p=0.02). Furthermore, a group of patients with GSTP1-GG genotype were significantly associated with reduced EFS comparing to those carrying other GSTP1 genotypes (p=0.049). GSTP1-GG genotypes had short time to treatment failure in a group of patients unresponsive to TKIs comparing to other GSTP1 genotypes (p=0.03).

CONCLUSIONS

This study highlights the significance of GSTM1 and GSTP1 polymorphisms on CML susceptibility and response to TKIs in the Argentinean population.

Genetic Polymorphisms of Multidrug Resistance Gene-1 (MDR1/ABCB1) and Glutathione S-Transferase Gene and the Risk of Inflammatory Bowel Disease among Moroccan Patients

Inflammatory bowel diseases (IBD) are multifactorial disorders resulting from environmental and genetic factors. Polymorphisms in MDR1 and GSTs genes might explain individual differences in susceptibility to IBD. We carried out a case-control study to examine the association of MDR1 (C1236T and C3435T), GSTT1, and GSTM1 polymorphisms with the risk of IBD. Subjects were genotyped using PCR-RFLP for MDR1 gene and multiplex PCR for GSTT1 and GSTM1. Meta-analysis was performed to test the association of variant allele carriage with IBD risk. We report that GSTT1 null genotype is significantly associated with the risk of CD (OR: 2.5, CI: 1.2–5, P = 0.013) and UC (OR: 3.5, CI: 1.5–8.5, P = 0.004) and can influence Crohn's disease behavior. The interaction between GSTT1 and GSTM1 genes showed that the combined null genotypes were associated with the risk of UC (OR: 3.1, CI: 1.1–9, P = 0.049). Furthermore, when compared to combined 1236CC/CT genotypes, the 1236TT genotype of MDR1 gene was associated with the risk of UC (OR: 3.7, CI: 1.3–10.7, P = 0.03). Meta-analysis demonstrated significantly higher frequencies of 3435T carriage in IBD patients. Our results show that GSTT1 null and MDR1 polymorphisms could play a role in susceptibility to IBD.

Explorative genetic association study of GSTT2B copy number variant in complex disease risks

BACKGROUND

Glutathione S-transferases (GSTs) are the main phase II enzymes involved in cellular detoxification. Through phase I and phase II detoxification reactions, the cell is able to detoxify endogenous and exogenous toxic compounds.

AIMS

This study focused attention on the GSTT2B copy number variant (CNV) in order to explore its involvement in the genetic pre-disposition to asthma, Alzheimer's disease (AD), allergic rhinitis (AR), essential hypertension (EH), hypothyroidism and recurrent miscarriage (RM).

METHODS

The study population consists of 1225 individuals divided into six case-control groups. The genotyping of the GSTT2B CNV was performed by using a duplex-PCR. Odds Ratios (ORs) were calculated, adjusting for the confounding variables, to estimate the association between GSTT2B CNV and the disease status.

RESULTS

The χ(2)-test and ORs did not show any association between this genetic marker and pathological phenotypes.

CONCLUSION

The data highlights that GSTT2B CNV is not associated with the investigated complex diseases in Italian patients. However, further investigations are necessary to replicate these findings in larger sample sizes and to explore other health-related phenotypes.

Association of glutathione S-transferase (GSTM1 and GSTT1) genes with chronic myeloid leukemia

Chronic myeloid leukemia (CML), as most of cancers results from a complex interaction between genetic or non genetic factors. Exposures to xenobiotics endogenous or exogenous associated with a reduced individual ability in detoxifying activity, constitutes a risk of developing cancer. It is known that polymorphism of glutathione S-transferases (GSTs) genes affects the detoxification of xenobiotics. Thus, we conducted a case-control study in which 92 patients (Mean age ± SD, 40.62 ± 12.7 years) with CML and 93 healthy unrelated controls (Mean age ± SD, 41.38 ± 13.4 years) have participated. GSTM1 and GSTT1 genotypes were determined by multiplex polymerase chain reaction. Logistic regression was used to assess the possible link between GSTM1 and GSTT1 null genotypes and CML as well as between combined genotypes and CML. GSTM1 null genotype frequency was slightly higher in patients than control (48.9% vs. 40.9%) but, it was not associated with CML (OR 95% CI, 1.4, 0.78-2.48; p = 0.271). Moreover, GSTT1 null genotype frequency showed a similar trend between patients and control (17.4% vs. 9.7%; OR 95% CI, 1.97, 0.82-4.71; p = 0.13). Surprisingly, GSTT1 null genotype was significantly associated with the risk of CML in males (OR 95% CI, 5, 1.25-20.1; p = 0.023). The combined GSTM1 present/GSTT1 null genotype was found to have a limited effect against the risk of CML (OR 95% CI, 0.3, 0.08-0.99; p = 0.049). Our findings have shown that GSTT1 null genotype might be a risk factor of CML in males. While, GSTT1 present genotype might be considered as protective against CML. However, further studies with a large sample size are needed to confirm our findings.

CAT, GPX1, MnSOD, GSTM1, GSTT1, and GSTP1 genetic polymorphisms in chronic myeloid leukemia: a case-control study

Oxidative damage at the DNA level may be promoted by high levels of reactive oxygen species (ROS), leading to genomic instability and increased neoplastic risk. Superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) enzymes are implicated in the prevention of DNA damage by ROS. The aim of the study was to investigate the relationships between CAT C262T, GPX1 Pro198Leu, MnSOD Ala16Val, GSTM1, GSTT1, and GSTP1 Ile105Val polymorphisms and the risk of CML. No association was observed between CML and variant genotypes of GPX1, MnSOD, GSTM1, and GSTT1 polymorphisms in any of the investigated cases. Our study suggests that the homozygous variant genotype of the GSTP1 Ile105Val gene polymorphisms may be associated with the risk of developing CML (OR = 2.5; 95% CI = 1.08–5.7; P value = 0.02), while the heterozygous genotype of the CAT C262T polymorphism seems to have a protective effect against CML (OR = 0.59, 95% CI = 0.39–0.89, P value = 0.01). In most cases, no association was found between laboratory parameters and prognostic factors and the variant genotype of investigated gene polymorphisms. We concluded that CAT, GPX, MnSOD, GSTM1, and GSTT1 gene polymorphisms are not associated with the risk of CML. Variant genotype of the GSTP1 Ile105Val gene polymorphisms may contribute to the risk of developing CML.

Epidemiological assessment of leukemia in Kazakhstan, 2003- 2012

Cancer is a major health problem facing the entire world, and Kazakhstan is not the exception. The aim of this study was to present an epidemiological assessment of leukemia in the population of Kazakhstan during 2003-2012. This descriptive and retrospective study was based on data obtained from all oncological organizations of the whole country. Age standardized incidence rates per 100,000 population for leukemia were calculated. Totally, 6,741 new cases of leukemia were registered in Kazakhstan during the 10 year period. The mean age of patients with leukemia was 48.5. The ASRs for leukemia among men and women were 5.3 and 3.6, respectively (p<0.001). In conclusion, our results showed a high incidence rate of leukemia in Kazakhstan, especially in the north of the country. The incidence of leukemia was significantly higher in males and increased with age. Determining and controlling important risk factors of leukemia may lead to decrease in its burden.

Glutathione S-transferase gene polymorphisms and susceptibility to chronic myeloid leukemia

Glutathione S-transferase (GST), a phase II metabolizing enzyme, plays an important role in the cellar defense system, and its activity may modulate leukemia risk. A large body of evidence has shown the possible relevance of functional polymorphisms of the genes that encode GSTs μ, π, and θ (GSTM1, GSTP1, and GST1, respectively) to the genetic susceptibility of chronic myeloid leukemia (CML). Because of the lack of available conclusive data, we performed a meta-analysis of all relevant available studies to derive a more precise estimation of the relationship. A comprehensive literature search of PubMed and Web of Knowledge electronic databases was conducted to collect relevant studies until December 20, 2013, and the extracted data were statistically analyzed using Review Manager version 5.2. Finally, 16 eligible studies were identified in the literature. The GSTT1 null genotype was associated with an increased risk of CML, as were the double null GSTT1 and GSTM1 genotypes. These findings suggest that heritable GST status influences the risk of developing CML and that more attention should be paid to carriers of these susceptibility genes.

Influence of CYP1A1, GST polymorphisms and susceptibility risk of chronic myeloid leukemia in Syrian population

In the present study, we investigated the associations of polymorphisms in cytochrome P450 gene (CYP1A1), glutathione S-transferase genes (GSTM1 and GSTT1) with chronic myelogenous leukemia (CML). A total of 126 patients with CML and 172 healthy volunteers were genotyped, and the DNA was isolated from their blood samples. The polymorphisms were assessed by polymerase chain reaction (PCR) restriction fragment length polymorphism-based methods and multiplex PCR. Logistic regression analyses showed significant risk of CML associated with CYP1A1 Val allele [odds ratio (OR) 3.3, 95% confidence intervals (CI) 1.96-5.53], (p < 0.0001) while CYP1A1 Val/Val homozygotes were observed only in the CML patients. There was statistically significant difference in the frequency of GSTM1 and GSTT1 null genotypes. The GSTT1-null genotype was slightly higher in 27% of CML cases and 16.7% of controls (OR 1.98, 95% CI 1.12-3.5) (p < 0.020). The GSTM1 null was higher in 42.8% of CML cases and 22.7% of controls (OR 2.55, 95% CI 1.54-4.22) (p < 0.00024). The individuals carrying CYP1A1 Ile/Val (AG) and GSTM1 null genotype have 9.9 times higher risk to be CML than those carrying CYP1A1 Ile/Ile (AA) and GSTM1 present genotype (OR 9.9, 95% CI 2.7-36.3) (p < 0.0001). This suggests that the association of the GSTM1 null genotype, either alone or in combination with GSTT1 null, with CYP1AI heterozygous leads to the CML risk.

Genetic polymorphisms of GSTM1 and GSTT1 genes in Delhi and comparison with other Indian and global populations

The glutathione S-transferases (GSTs) are involved in the metabolism of many xenobiotics, including an array of environmental carcinogens, pollutants, and drugs. Genetic polymorphisms in these genes may lead to inter- individual variation in susceptibility to various diseases. In the present study, GSTM1 and GSTT1 polymorphisms were analysed using a multiplex polymerase chain reaction in 500 normal individuals from Delhi. The frequency of individuals with GSTM1 and GSTT1 null genotypes were 168 (33.6%) and 62 (12.4%) respectively, and 54 (10.8%) were having homozygous null genotype for both the genes GSTM1 and GSTT1 simultaneously. The studied population was compared with reported frequencies from other neighbouring state populations, as well as with those from other ethnic groups; Europeans, Blacks, and Asians. The prevalence of homozygous null GSTM1 genotype is significantly higher in Caucasians and Asians as compared to Indian population. The frequency of GSTT1 homozygous null genotypes is also significantly higher in blacks and Asians. We believe that due to large number of individuals in this study, our results are reliable estimates of the frequencies of the GSTM1, GSTT1 in Delhi. It would provide a basic database for future clinical and genetic studies pertaining to susceptibility and inconsistency in the response and/or toxicity to drugs known to be the substrates for GSTs.