Influence of GSTP-1 Genetic Variation on Prognosis of Postoperative Glioblastoma Patients Received Temozolomide Combined with Radiotherapy Regimens

Abstract

Objective To investigate the influence of Glutathione S-transferase P-1 (GSTP-1) genetic variation on the prognosis of postoperative glioblastoma patients received temozolomide combined with radiotherapy regimens. Methods We included 175 glioblastoma patients received temozolomide combined with radiotherapy after surgical resection. Peripheral blood of the glioblastoma patients was collected for the genotyping of GSTP-1 genetic variation. Additionally, RNA was extracted from peripheral blood mononuclear cell specimens of patients prior to chemotherapy for GSTP-1 mRNA expression analysis. The correlation analysis was performed between the genetic variation and other characteristics. Results The prevalence of Ile105Val among the study population were as follows: 119 cases (68.00%) of G/G genotype, 51 cases (29.14%) of G/A genotype, 5 cases (2.86%) of A/A genotype, minimum allele frequency of Ile105Val was 0.17; the distribution of three genotypes were in accordance with Hardy-Weinberg Equilibrium (P=0.868). The median progression-free survival (mPFS) of patients with G/A+A/A genotypes and GG genotype were 4.4 and 6.9 months, respectively (P=0.005); the median overall survival (mOS) of the two genotypes was 11.0 and 15.3 months, respectively (P < 0.001). G/A+A/A genotype was an independent factor for OS (OR=1.68, P=0.011). Additionally, the GSTP-1 mRNA expression in the patients with G/A+A/A genotypes were significantly higher than those in the G/G genotype patients (P < 0.001). Conclusion The prognosis of postoperative glioblastoma patients received temozolomide combined with radiotherapy regimens may be influenced by GSTP-1 Ile105Val genetic variation through mediating the mRNA expression of GSTP-1.

Keywords

• glioblastoma
• gstp-1
• polymorphism
• prognosis