关键词: 肿瘤, 鳞状细胞, 基因甲基化, 甲基特异性PCR

Abstract: Objective To investigate the relationship between the protein expression and the methylation in promoter region of death-associated protein kinase DAPK gene and oral squamous cell carcinoma (OSCC) and study the mechanism of the DAPK protein expression changes and the gene therapy method in OSCC.Methods The methylation rates in promoter region of DAPK gene in 23 cases of normal oral mucous membrane and 53 cases of OSCC tissues were detected by methylation specific PCR,and the expression rates of DAPK protein were analyzed by immunohistochemistry.Results There was no methylation in promoter region of DAPK gene in normal oral mucous membrane.The exhaustive methylation in promoter region of DAPK gene in 30 cases（56.60%）and partial methylation in 8 cases （15.09%）in OSCC were detected.The total methylation rate was 71.69% in OSCC,there was significant difference compared with normal oral mucous membrane（P<0.01）.The expression of DAPK protein was positive in 23 cases (100%) of normal oral mucous membrane and was down regulated in 36 cases (67.92%) of OSCC tissues,there was significant difference（P<0.01）.There was a significant difference in the methylation rate between down-regulated expression group in OSCC tissues（32/36,88.89%） and normal expression group（6/17,35.29%）.（P<0.01）.Conclusion The DNA methylation in promoter region might be one of the mechanisms that contribute to down-regulation of the expression of DAPK protein.The loss of DAPK gene’s function caused by the methylation in promoter region may relate to the tumorigenesis of OSCC.

Key words: neoplasms, squamous cell, gene methylation, methylation specific PCR