Polymorphisms in genes involved in drug detoxification and clinical outcomes of anthracycline-based neoadjuvant chemotherapy in Chinese Han breast cancer patients

From Six Gene Polymorphisms of the Antioxidant System, Only GPX Pro198Leu and GSTP1 Ile105Val Modulate the Risk of Acute Myeloid Leukemia

Oxidative stress might contribute to the occurrence of cancers, including the hematological ones. Various genetic polymorphisms were shown to increase the quantity of reactive oxygen species, a phenomenon that is able to induce mutations and thus promote cancers. The purpose of the study was to evaluate the association between CAT C262T, GPX1 Pro198Leu, MnSOD Ala16Val, GSTM1, GSTT1, and GSTP1 Ile105Val gene polymorphisms and acute myeloid leukemia risk, in a case-control study comprising 102 patients and 303 controls. No association was observed between AML and variant genotypes of CAT, MnSOD, GSTM1, and GSTT1 polymorphisms. Our data revealed a statistically significant difference regarding the frequencies of GPX1 Pro198Leu and GSTP1 Ile105Val variant genotypes between AML patients and controls (p < 0.001). Our results showed no association in the distribution of any of the CAT C262T, GPX1 Pro198Leu, GSTM1, GSTT1, and GSTP1 polymorphisms regarding age, gender, FAB subtype, cytogenetic risk groups, FLT3 and DNMT3 gene mutations, and overall survival. Our data suggests that the presence of variant allele and genotype of GPX1 Pro198Leu and GSTP1 Ile105Val gene polymorphisms may modulate the risk of developing AML.

ABCB1 (rs1128503) polymorphism and response to chemotherapy in patients with malignant tumors-evidences from a meta-analysis

Numerous papers have reported ABCB1 polymorphisms are associated with the response to chemotherapy of cancers. The inconclusive results call for a comprehensive analysis, for the sample size of the published studies is comparatively small. Therefore, a comprehensive meta-analysis was performed on the basis of the published studies for an accurate estimation of such association. Altogether 8 comparative studies including 2463 cancer patients were involved in our meta-analyses. ABCB1 C1236T (rs1128503) polymorphism was shown to be associated with tumor response to chemotherapy in cancer patients under the dominant model (OR=1.72, 95% CI=1.09-2.73, P=0.177, I(2)=36.60%) and additive model (OR=1.99, 95% CI=1.39-2.85, P=0.222, I(2)=25.90%). A subgroup meta-analysis indicated a significant association under dominant model between ABCB1 C1236T (rs1128503) polymorphism and breast cancer in the Asians (OR=2.15, 95% CI=1.22-3.77, P=0.210, I(2)=33.70%). These results suggest that ABCB1 C1236T (rs1128503) might contribute to the tumor response to chemotherapy in cancers from the Asians, especially in the osteosarcoma and breast cancer.

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.