AIM: To explore the expression of heparanase gene, CD44v6,MMP-7 and nm23 proteins in human gastric carcinoma as well as their relationship with the clinicopathological factors. METHODS: Reverse transcription polymerase chain reaction (RT-PCR) was used to measure the expressions of heparanase mRNA in 43 human gastric carcinomas and 10 adjacent normal gastric tissues. Streptavidin-peroxidase (S-P) two step method was used to measure the immunohistochemical expression of CD44v6, MMP-7 and nm23protein in 43 human gastric carcinomas.RESULTS: The expression of heparanase gene was positive in 29 cases of gastric cancer with a positive rate of 67.4%,which was significantly higher than those in adjacent normal gastric tissues (P＜0.05). The heparanase mRNA expression was significantly related to advanced stage of disease, serosal infiltration, lymph node metastasis and size of tumors (P＜0.05), but not related to tumor location, gross and histological types of the cancer, peritoneal dissemination and liver metastasis (P＞0.05). The positive rate of CD44v6, nm23 and MMP-7 proteins was 76.7%, 37.2% and 60.5%, respectively. The CD44v6 protein expression was significantly related to serosal infiltration, lymph node metastasis and TNM stage of disease (P＜0.05). The nm23 protein expression was significantly related to the tumor gross appearance, lymph node and peritoneal metastasis (P＜0.05). The MMP-7 protein expression was significantly related to serosal infiltration and TNM stage of disease (P＜0.05). In an attempt to measure the association between these agents, we found that the expression of heparanase mRNA had significantly negative correlation with the expression of CD44v6 and MMP-7 protein (P＜0.05), the expression of MMP-7 protein had significantly positive correlation with the expression of CD44v6 protein (r=0.568, P＜0.05), the expression of MMP-7 protein had no correlation with the expression of nm23 protein (P＞0.05), and the expression of nm23 protein had no correlation with the expression of CD44v6 protein (P＞0.05). CONCLUSION: Despite their different mechanisms of action, heparanase, CD44v6 and nm23 may play important roles in the invasive infiltration and lymph node metastasis in gastric carcinomas. Instead of metastatic spreading, MMP 7 may be just related to the invasion of gastric carcinomas.However, co-detection of these factors may be important to predict metastatic spreading in such patients.