Does MDR1 promoter methylation affect temozolomide resistance? A clinical study in patients with glioblastoma

Abstract

Purpose: The multidrug resistance 1 (MDR1) gene expression and its epigenetic status may be an important factor in the chemotherapeutic resistance of glioblastoma (GB). The aim of this study was to analyze the effect of the MDR1 promoter methylation status on GB tumor tissue related to patient survival, chemotherapy resistance, and recurrence of the disease. Materials and methods: Thirty-six patients underwent surgery for GB at the Neurosurgery Department of Ankara University School of Medicine. The patients' clinical information and the MDR1 methylation status of the tumor tissues were compared to determine the effects on patient survival, chemotherapy resistance, and tumor recurrence. Results: Patients with MDR1 methylated GB had statistically significantly (p<0.001) shorter survival times. Early recurrence was detected in 25% of the patients with unmethylated tumor tissues and in 39.3% with hemimethylated tumor tissues. Conclusion: Instead of using the standard chemotherapeutics in all the patients with GB, tissue-specific medications must be chosen while taking into consideration the epigenomic characteristics and expression status of the tumor because of the genetic heterogeneity of GB. This is the first study to show the association between MDR1 promoter methylation and the clinical data of GB in the literature. © 2022, Pamukkale University. All rights reserved.