A promoter methylation pattern in the N-methyl-D-aspartate receptor 2B gene predicts poor prognosis in esophageal squamous cell carcinoma

Purpose: To investigate whether the promoter methylation pattern in N-methyl-D-aspartate receptor 213 (NMDAR2B) is correlated with clinical features of human esophageal squamous cell carcinoma (ESCC), the methylation status of the gene was examined at three different sites (P1, P2, and 173) where two CpG islands reside within 1 kb upstream of the transcription start site. Experimental Design: Three independent modalities for methylation analysis (bisulfite sequencing, combined bisulfite restriction analysis, and Taq Man methylation-specific PCR) were done to analyze total 67 ESCC tissues that included 43 primary tumors with well-characterized clinicopathologic variables including patient outcome. Results: Using an optimized cutoff value based on quantitative methylation-specific PCR, we found that patients with higher NMDAR213 methylation ratio in the proximal region (P1) showed a worse 5-year disease-specific survival rate than those without NMDAR213 methylation (P < 0.006). A significant correlation was also seen between NMDAR213 promoter methylation and the presence of vascular permeation (P = 0.03). Conclusion: NMDAR213 promoter methylation could be a clinically applicable marker in ESCC.