P>Objective To investigate the relationship between expression of EM>REG/EM>Iα gene and its clinicopathologic parameters, the survival rate in the patients with primary gastric cancer. Methods Using RT-PCR after extracting RNA from paraffinembedded materials and immunohistochemical techniques, EM>REG/EM>Iα gene expression was investigated in 235 samples. And the relation among their results with the clinicopathologic parameters of primary gastric carcinoma was discussed in experiment by SPSS 13.0 statistic software. Results The positive EM>REG/EM>Iα mRNA was 78% (183/235) of primary gastric carcinoma and the positive rate of EM>REG/EM>Iα protein was 31.1% (73/235) in 235 patients with primary gastric carcinoma. EM>REG/EM>Iα gene expression in infiltrating tumors was found to be significantly higher compared with localized tumors (P<0.05). EM>REG/EM>Iα gene was closely linked to the infiltrative growth pattern, signet ring cell and poorly differentitated adencarcinoma. The incidence of venous invasion of EM>REG/EM>Iα genepositive differentiated adenocarcinoma was significantly higher than that of EM>REG/EM>Iα genenegative tumors. Moreover, the patients with EM>REG/EM>Iα genepositive differentiated adenocarcinoma were found to have a significantly poorer prognosis as compared with EM>REG/EM>Iα genenegative tumor patients. Conclusions The results of the experiment demonstrated that the expressio