Sensitive Detection and Conjoint Analysis of Promoter Methylation by Conjugated Polymers for Differential Diagnosis and Prognosis of Glioma

Abstract

Glioma is the most common primary tumor in the central nervous system (CNS) with the worst prognosis. Accurate pathological diagnosis has always been a challenge for optimal management of glioma. Promoter methylation is an important mechanism of epigenetic silencing tumor-suppressor genes and a potential biomarker for differential diagnosis and prognosis. Herein, using the cationic conjugated polymer (CCP)-based fluorescence resonance energy transfer (FRET) technique, we realized a highly sensitive detection of promoter methylation in clinical samples of minimal methylation degree (1.25%) and trace DNA quantity (10 ng/μL). Results for three glioma-related genes (MGMT, CDKN2A, and TERT) were combined in a diagnostic classifier to analyze the glioma-CpG island methylator phenotype (G-CIMP), which achieved a sensitivity of 80% at a maximum specificity of 100% for a glioma diagnosis. Kaplan-Meier survival curves and Pearson correlation analysis revealed that the prognosis of glioma patients with high G-CIMP scores (>5) was significantly better than those with low G-CIMP scores, especially in diffuse midline glioma and astrocytoma. This CCP-based FRET technique for determining G-CIMP status could provide patients with rapid and reasonably accurate diagnosis of glioma, as well as a valuable prognostic prediction that can guide individual treatment.

Keywords: FRET technique; cationic conjugated polymer; diagnosis; glioma; prognosis; promoter methylation.