To screen out the differentially methylated DNA sequences between gastric primary tumor and metastatic lymph nodes, test the methylation difference of gene PTPRG between primary gastric tumor and metastatic lymph nodes, and test the regulatory function of 5-aza-2'-deoxycytidine which is an agent with suppression on methylation and the level of methylation in gastric cancer cell line.
To screen out the differentially methylated DNA sequences between gastric primary tumor and metastatic lymph nodes, test the methylation difference of gene PTPRG between primary gastric tumor and metastatic lymph nodes, and test the regulatory function of 5-aza-2'-deoxycytidine which is an agent with suppression on methylation and the level of methylation in gastric cancer cell line.