Objective: To explore the relationship between hypermethylation of the promoter of death-associated protein kinase (DAPK) gene and laryngeal squamous cell cancer.
Methods: Promoter hypermethylation and mRNA expression of DAPK gene were detected by methylation-specific PCR, RT-PCR and gene sequencing.
Results: Among the 58 patients with laryngeal squamous cell cancer, hypermethylation of DAPK promoter was detected in 39 cases (67.2%). There was no significant difference in hypermethylation in relation to pathological grade and clinical staging, but a highly significant difference was observed between patients with and without lymph node metastasis (N0 and N1) (P < 0.001). DAPK promoter hypermethylation was detected in tumor adjacent tissues in 6 of the 58 cases. DAPK mRNA was not expressed in all laryngeal squamous cell cancers having hypermethylation of DAPK promoter, whereas it was expressed in normal laryngeal mucosa, laryngeal squamous cell cancers without hypermethylation and tumor adjacent tissues.
Conclusion: Hypermethylation of DAPK promoter is associated with loss of its transcription in laryngeal squamous cell carcinoma. The high frequency hypermethylation of DAPK promoter illustrates its potential clinical application as tumor marker for diagnosis and prognosis.