Abstract: Objective To study the expression of the tumor suppressor gene thyroid stimulating hormone receptor (tshr) and p16 in papillary thyroid carcinoma(PTC),analyse of the relationship between two promoter methylation and clinicopathological parameters,and to explore the correlation between the occurrence of tumor and the aberrant promoter methylation of two tumor suppressor genes. MethodsThe promoter methylation status of two tumor suppressor gene in 50 cases of PTC and 32 cases of controls were examined by using methylation-specific PCR technique (MSP). Using gene sequencing to test if the hypermethylation existed in promoter of two tumor suppressor genes. The relationship of two tumor suppressor genes promoter methylation and the correlation between their methylation and the main clinical pathologic parameters was analyzed by SPSS 13.0 software. Results Hypermethylation was detected in 68.0% (34/50) tshr gene and 54.0%(27/50) p16 gene in PTC in promoter region while hypermethylation was detected in 21.9%(7/32)tshr gene and 15.6%(5/32) p16 gene in control in promoter region.The rate of promoter methylation in PTC was significantly higher than that in control (the χ² was 16.61 and 12.08 separately,P<0.05). The sequencing confirmed that there were the CG →TG transmission in promoter of two tumor suppressor genes.The correlation analysis showed that there was no association between tshr and p16 gene hypermethylation(r=0.23,P>0.05);The rate of tshr and p16 gene methylation was higher in PTC with lymph node metastasis than that without lymph node metastasis(the χ² was 5.82 and 5.10 separately,P<0.05). Conclusion Methylation of two tumor suppressor genes in promoter region is a common molecular event and may be involved in the genesis and development of human PTC.tshr and p16 gene promoter methylation may play a role in malignant progression of PTC.

Key words: papillary thyroid carcinoma, tumor suppressor gene, methylation, clinicopathological, relevance