Hypermethylation of DcR1, DcR2, DR4, DR5 gene promoters and clinical significance in tongue carcinoma

Objective: Tongue squamous cell carcinoma (TSCC) is one of the most common malignancies in the oral cavity, and its incidence and mortality have been constantly increasing these years. A large number of tumor suppressor genes are involved in the development of the TSCC and it has been reported that the aberrant hypermethylation of tumor suppressor genes may play a key role in the process of the TSCC. In this study, we sought to analyze the association of methylation of DcR1, DcR2, DR4 and DR5 gene promoters and clinical significance in the TSCC to evaluate association between methylation of DcR1, DcR2, DR4 and DR5 gene and Clinical Significance in tongue squamous cell carcinoma. Methods: Methylation-specific PCR(MSP) was used to analyze the methylation of the promoters of TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) receptors in 45 TSCC cases. Real-Time PCR was used to detect the expression of the DcR1, DcR2, DR4 and DR5 gene. Results: All the four genes (DcR1, DcR2, DR4 and DR5) showed different methylation of promoters in TSCC, while methylation of these promoters in paired adjacent normal tissues were almost undetectable. Patients with high methylation index were diagnosed at younger age when compared with the ones with low methylation index. DcR1 and DR4 hypermethylation was correlated significantly with patients' TNM stage. Conclusions: Methylation of DcR1, DcR2,DR4 and DR5 promoters are found in TSCC and may associate with its occurrence and development. Taking the reversibility of methylation into account, methylation is a potential targeted therapy of TSCC.