Glutathione S-transferase pi polymorphism contributes to the treatment outcomes of advanced non-small cell lung cancer patients in a Chinese population

GSTP1 Ile105Val polymorphism among North Indian lung cancer patients treated using monotherapy and poly-pharmacy

BACKGROUND

Genetic polymorphism within the P1 isoenzyme of the Glutathione-S-Transferase (GST) family is found to modulate and alter the enzyme activity of GSTP1 protein and thus may result in a change of sensitivity to platinum-based chemotherapy. We investigated the relationship between GSTP1 Ile¹⁰⁵Val polymorphisms and overall survival, treatment response, and for both hematological and non-hematological toxicity of advanced North Indian lung cancer patients undergoing platinum-based double chemotherapy.

METHODS

The polymorphism of GSTP1 Ile¹⁰⁵Val in North Indian lung cancer patients was assessed by polymerase chain reaction-restriction fragment length polymorphism. A total of 682 lung cancer patients were enrolled in the study, and it was observed that patients who were carrying both the mutant alleles (Val/Val) for the GSTP1 polymorphism showed a higher trend of median survival time (MST) as compared to the patients bearing the wild type of genotype (Ile/Ile) (MST = 8.30 vs. 7.47, p = 0.56). Based on toxicity profiling, we observed that lung cancer patients with the mutant genotype of GSTP1 (Val/Val) had an increased risk of leukopenia (OR = 2.41; 95% CI = 1.39-4.18, p = 0.001) as compared to subjects carrying both copies of the wild alleles (Ile/Ile). Our data suggested that patients with heterozygous genotype (Ile/Val) had a 2.14-fold increased risk of developing severe anemia (OR = 2.14, 95% CI = 0.97-4.62, p = 0.03). Our data also showed that in small cell lung carcinoma (SCLC) patients' polymorphism of GSTP1 was associated with thrombocytopenia (χ2 test = 7.32, p = 0.02).

CONCLUSIONS

Our results suggest that GSTP1 Ile¹⁰⁵Val polymorphism could be a predictive biomarker for hematological toxicity, like leukopenia and anemia, but not thrombocytopenia or neutropenia.

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.

Glutathione S-Transferase Gene Polymorphisms are Associated with an Improved Treatment Response to Cisplatin-Based Chemotherapy in Patients with Non-Small Cell Lung Cancer (NSCLC): A Meta-Analysis

BACKGROUND Previous studies have shown an association with glutathione S-transferase (GST) gene polymorphisms in patients with non-small cell lung cancer (NSCLC) and treatment response. This study aimed to undertake a literature review and meta-analysis of GST gene polymorphisms, including GSTT1, GSTM1, and GSTP1 IIe105Val, and the treatment response to cisplatin-based chemotherapy in patients with NSCLC. MATERIAL AND METHODS A literature search was undertaken of the main medical publication databases for publications, up to March 2017, on the association between GSTT1, GSTM1, and GSTP1 IIe105Val polymorphisms and the clinical outcome in patients with NSCLC treated with cisplatin-based chemotherapy. A random fixed-effects model was used to calculate the pooled odds ratio (OR) and 95% confidence interval (CI) to evaluate the associations, considering multiple genetic models. A subgroup analysis according to ethnicity was performed. RESULTS Twenty-three published studies were identified that showed that both the null GSTM1 and the GG genotype of GSTP1 IIe105Val were associated with improved treatment response to cisplatin-based chemotherapy (GSTT1 present/null: OR=1.328; 95% CI, 1.074-1.643) (GSTP1 GG + AG vs. AA: OR=0.596; 95% CI, 0.468-0.759). In subgroup analysis, the GSTP1 polymorphism was significantly associated with treatment response in East-Asian patients, but not in Caucasian patients. CONCLUSIONS Meta-analysis showed that the GG genotype of GSTP1 IIe105Val and the null GSTM1 genotype were associated with an improved treatment response to cisplatin-based chemotherapy in patients with NSCLC, especially in East-Asian patients.

Predictive assessment in pharmacogenetics of Glutathione S-transferases genes on efficacy of platinum-based chemotherapy in non-small cell lung cancer patients

The influences of glutathione s-transferase P1, M1, and T1 variants on the efficacy of platinum-based chemotherapy in non-small cell lung cancer (NSCLC) patients were inconsistent in previous studies. Our meta-analysis enrolled 31 publications including 5712 patients and provided more convincing and reliable conclusions. Results showed that GSTP1 IIe105Val IIe/Val and Val/Val Asian patients were more likely to have better response rates compared to IIe/IIe patients (odds ratio (OR) = 1.592, 95% confidence intervals (CIs), 1.087-2.332, P = 0.017). The Asian patients bearing the favorable GSTM1 null genotype were more likely to have better response rates to platinum-based chemotherapy compared to those patients with the unfavorable GSTM1 present genotype (OR = 1.493 (1.192-1.870), P < 0.001). Caucasian lung cancer patients bearing GSTT1 null genotype might be more closely associated with shorter survival time and higher risks of death than the GSTT1 present patients (hazard ratio (HR) = 1.423, CI = 1.084-1.869, P = 0.011). Our meta-analysis suggested that the GSTP1 IIe105Val, GSTM1 and GSTT1 null variants might be predictive factors for the efficacy of platinum-based chemotherapy to NSCLC patients. The use of GSTP1 IIe105Val, GSTM1 and GSTT1 null polymorphisms as predictive factors of efficacy of personalized platinum-based chemotherapy to NSCLC patients requires further verification with multi-center, multi-ethnic and large-sample-size pharmacogenetic studies.