Relationship between DAPK methylation and gene inactivation in papillary thyroid carcinoma

Abstract

To investigate the relationship between the methylation of death-associated protein kinase (DAPK) promoter and gene inactivation in papillary thyroid carcinoma, the technique of methylation-specific polymerase chain reaction (PCR (MSP)) was applied to detect the methylation status of DAPK gene promoter in 70 cases of papillary thyroid carcinoma (study group) and in 50 cases of corresponding adjacent tissues (control group). Immunohistochemical method was used to detect the protein expression; besides, the relationship of DAPK methylation and gene inactivation with pathological factors of papillary thyroid cancer was analyzed. The methylation rate of DAPK was 16% (8/50) in the control group and 71.4% (50/70) in the study group with the difference being statistically significant (χ2 = 19.724, P < 0.01). The methylation of DAPK gene promoter was not associated with age, sex, tumor size, TNM stage, and thyroid capsular infiltration in the study group with papillary thyroid carcinoma ( P > 0.05), but was associated with lymph node metastasis ( P < 0.05). Spearman’s rank correlation analysis showed that the methylation of DAPK promoter was negatively correlated with the expression of DAPK (r = −0.793, P < 0.01). The methylation of CpG island in the promoter region of DAPK gene can lead to gene inactivation and may be involved in the occurrence of papillary thyroid carcinoma.