Effect of Glutathione S-transferase mu 1 ( GSTM1 ) gene polymorphism on chronic myeloid leukemia risk and Imatinib treatment response

Genetic Insights Into Leukemia Susceptibility in the Arab Population: A Scoping Review

As per the Global Cancer Observatory, the WHO Eastern Mediterranean region (which includes the Arabic countries) ranks highest for age-standardized mortality rate at 4 per 100,000, thus indicating a probable role of genetic associations. Identifying the genes associated with leukemia in the Arab population is crucial for effective preventive and treatment strategies. This scoping review aimed to determine the nature and extent of research available on the genes associated with the major types of leukemia among the Arab population. As per the scoping review guidelines, a comprehensive search was conducted in PUBMED and Google Scholar for articles published before 01/10/2023 and focused on leukemia-related genes among the Arab population. In total 119 studies, focusing on genes associated with leukemia met the inclusion criteria. On reviewing these studies, 27 genes were found to be associated with ALL, 33 genes with AML, seven genes with CLL, and 14 genes with CML. The majority of these genes were associated with an increased risk for the disease. Notably, the 119 studies covered only nine out of the 22 Arab countries, with 56 studies carried out in Egypt, exhibiting an imbalance in the regional distribution of the research landscape. Thus, indicating the inadequacy of research on leukemia genetics in the Arab region in comparison to the Western studies. This finding highlights the need for extensive research in the Middle Eastern region to gain geographically heterogeneous genetic information about the Arab population. In conclusion, this scoping study highlights the genes associated with the major types of leukemia among the Arab population and also indicates the need for comprehensive and regionally balanced research on leukemia genetics in Middle Eastern countries. Addressing this gap is essential to provide robust genetic data that can be used for targeted interventions to improve leukemia outcomes in the Middle East. Increased research efforts in all Middle Eastern countries will contribute to a greater understanding of genetic predisposition and help develop effective prevention strategies and treatments tailored to this population.

Influence of genetic polymorphisms in glutathione-S-transferases gene in response to imatinib among Brazilian patients with chronic myeloid leukemia

Polymorphism in metabolizing enzymes can influence drug response as well as the risk for adverse drug reactions. Nevertheless, there are still few studies analyzing the consequence of polymorphisms for the Glutathione-S-transferases (GST) gene to drug response in chronic myeloid leukemia (CML). This study reports, the influence of GSTP1*B and GSTT1/GSTM1null polymorphisms in response to imatinib in CML patients in a Brazilian population. One hundred thirty-nine CML patients from the Clinical Hospital of Goiânia, Goiás, Brazil, treated with imatinib were enrolled in this study. Genotyping of GSTT1 and GSTM1 genes deletions were performed by qPCR and of GSTP1 gene was performed by RFLP-PCR. The frequency of GSTP1*1B, GSTT1 and GSTM1null polymorphisms were determined for all patients. The influence of each patient's genotypes was analyzed with the patient's response to imatinib treatment. Brazilian CML patients revealed GSTT1 and GSTM1 genes deletions. GSTT1 deletion was found in 19.3% of patients and GSTM1 deletion in 48.7% of patients with CML. GSTT1/GSTM1 deletion was found in 11.7% in Brazilian CML patients. The "G allele" of GSTP1*B, is associated with later cytogenetic response in imatinib therapy. While, the gene presence combined with GG genotype (GSTM1 present/GSTPI-GG) conferred a tend to a later cytogenetic response to patients. GSTP1*B and GSTT1/GSTM1null polymorphisms influence treatment response in CML. Brazilian CML patients presenting GSTP1 AA/AG genotypes alone and in combination with GSTT1 null reach the cytogenetic response faster, while patients presenting GSTP1-GG and GSTMI positive genotypes may take longer to achieve cytogenetic response. As a result, it allows a better prognosis, with the use of an alternative therapy, other than reducing treatment cost.

Association Between Glutathione-S-Transferase Gene Polymorphisms and Responses to Tyrosine Kinase Inhibitor Treatment in Patients with Chronic Myeloid Leukemia: A Meta-analysis

BACKGROUND

Although many earlier studies revealed an effect of glutathione-S-transferase (GST) gene polymorphisms on tyrosine kinase inhibitor (TKI) treatment responses in chronic myeloid leukemia (CML) patients, the significance of this relationship remains controversial.

OBJECTIVE

This study aimed to review and meta-analyze treatment responses to TKIs in patients with CML and GST gene polymorphisms, including GSTT1, GSTM1, and GSTP1.

PATIENTS AND METHODS

We searched four medical databases, PubMed, Web of Science, the Cochrane Library, and Embase, by using keywords related to GST gene polymorphisms and clinical responses in CML patients receiving TKI treatment. The meta-analysis was performed using RevMan version 5.3 and Comprehensive Meta-Analysis software version 3.0. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to examine the association between GSTT1, GSTM1, and GSTP1 polymorphisms and TKI treatment responses in patients with CML.

RESULTS

The null polymorphisms of GSTT1 and GSTM1 did not affect TKI treatment responses, while the GSTP1 Ile105Val polymorphism had a significant impact on responses to TKI. Patients who were GSTP1 variant allele carriers (AG + GG) had poor responses to TKI treatment compared to patients who were wild-type homozygote carriers (AA) (OR 1.85, 95% CI 1.31-2.62; p < 0.001).

CONCLUSIONS

This meta-analysis of patients with CML showed that G allele carriers with GSTP1 Ile105Val polymorphism had significantly worse responses to TKI treatment than wild-type homozygote carriers.

Pharmacogenetics and the treatment of chronic myeloid leukemia: how relevant clinically? An update

Despite the excellent efficacy and improved clinical responses obtained with imatinib mesylate (IM), development of resistance in a significant proportion of chronic myeloid leukemia (CML) patients on IM therapy have emerged as a challenging problem in clinical practice. Resistance to imatinib can be due to heterogeneous array of factors involving BCR/ABL-dependent and BCR/ABL-independent pathways. Although BCR/ABL mutation is the major contributory factor for IM resistance, reduced bio-availability of IM in leukemic cells is also an important pharmacokinetic factor that contributes to development of resistance to IM in CML patients. The contribution of polymorphisms of the pharmacogenes in relation to IM disposition and treatment outcomes have been studied by various research groups in numerous population cohorts. However, the conclusions arising from these studies have been highly inconsistent. This review encompasses an updated insight into the impact of pharmacogenetic variability on treatment response of IM in CML patients.