Abstract: Objective To investigate the role and significance of methylation status and protein expression of the Runx3 gene in serrated lesions and carcinogenesis pathway. Methods The Runx3 gene promoters methylation were detected with the Taqman probe based real-time PCR(Methylight) technology in 77cases serrated lesions(29 cases of hyperplastic polyps, 29 cases of sessile serrated adenoma/polyp and 19 traditional serrated adenoma) , 16 cases of normal mucosa tissues and 14 cases of colorectal cancer. At the same time, immunohistochemical staining was utilized to detect the expression of Runx3, and to analyze the relationship of them. Results The rates of methylation of the Runx3 gene in normal mucosa tissues , HP, SSA/P, TSA and CRC were 12.5%(2/16)、17.2%(5/29)、51.7%(15/29)、63.2%(12/19) and 78.6%(11/14).The results of Immunohistochemistry showed that the positive expression of Runx3 in normal mucosa tissues , HP, SSA/P, TSA and CRC were 81.3%(13/16), 72.2%(21/29), 48.3%(14/29), 31.6% (6/19)and 21.4%(3/14). The Runx3 methylayion was correlated negatively with the expression of Runx3 protein in SSA/P, TSA and CRC (P<0.05). Conclusion Runx3 gene promoter region methylation induced Runx3 protein expression is cut or missing, the main reasons for the serrated lesions especially the occurrence of serrated adenoma and cancer pathyway plays an important role.

Key words: DNA methylation , Runx3 gene, Serrated lesions, Immunohistochemistry