GSTT1 null and rs156697 Polymorphism in GSTO2 Influence the Risk and Therapeutic Outcome of B-Acute Lymphoblastic Leukemia Patients

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.

Increased Risk of Acute Lymphoblastic Leukemia in Adult Patients with GSTM1 Null Genetic Polymorphism

Purpose

Glutathione S-transferases (GSTT1 and GSTM1) detoxify various endogenous and exogenous compounds and provide cytoprotective role against reactive species. This study aimed to assess the frequency of GSTT1, and GSTM1 polymorphisms in newly diagnosed Sudanese adult patients with acute lymphoblastic leukemia (ALL) and to evaluate the association of these polymorphisms with age, gender and type of ALL.

Patients and Methods

This case–control study included 128 adult Sudanese, untreated newly diagnosed patients with ALL, aged 18 to 74 years and 128 age-gender matched healthy controls. Deletional polymorphisms of GSTT1 and GSTM1 genes were genotyped through a multiplex polymerase chain reaction (PCR) assay using β-globin gene as an internal positive control.

Results

The genotypic frequency of GSTT1 null polymorphism was 22.7% in cases and 14.8% in controls (OR = 1.68, P = 0.111). Statistically significant differences were noted in the frequencies of GSTM1 null polymorphism in cases and controls (OR = 3.7, P = <0.001). Combined GSTT1 null and GSTM1 null gene polymorphisms showed statistically significant difference in patients with ALL as compared to controls (OR = 6.5, CI 95% = 1.42–29.74, P < 0.001).

Conclusion

Irrespective of age at diagnosis, gender, and phenotype of ALL, GSTM1 null polymorphism either alone or in combination with GSTT1 null polymorphism poses significantly increased risk of developing ALL in adults.