CYB5R2 and nasopharyngeal carcinoma: We revealed a frequent and tumor-specific hypermethylation of the CYB5R2 promoter in NPC and a significant association of CYB5R2 promoter hypermethylation with lymph node metastasis, which suggests that the epigenetic state of the CYB5R2 promoter may serve as a diagnostic biomarker and present a possible therapeutic target for NPC.