OBJECTIVETo investigate the correlation between expression of the osteopontin (OPN) and invasion and metastases in gastric cancer.

METHODSThe expression of OPN, NF-kappaB p65 and matrix metallo-proteinase 9 (MMP-9) was detected by immunohistochemistry in non-cancer gastric tissue (n = 12 cases) and gastric cancer tissue (n = 72 cases).

RESULTS(1) OPN, NF-kappaB p65 and MMP-9 were not expressed in 12 non-cancer gastric tissue samples(group A). Their expression rates were 43.3%, 40.0% and 46.7% respectively in 30 gastric cancer samples without lymph nodes metastasis (group B), but they increased to 76.9%, 73.1% and 80.8% in 26 gastric cancer samples with lymph nodes metastases (group C), and 87.5%, 81.3% and 93.8% respectively in 16 gastric cancer samples with lymph node and distant metastases (group D). (2) There were statistically significant differences in their expressions between group D and group B (P(a) = 0.004, P(c) = 0.007, P(e) = 0.002), and between group C and group B (P(b) = 0.011, P(d) = 0.013, P(f) = 0.009). (3) Despite some differences in positive expression rates, correlations existed between OPN and NF-kappaB p65, and between NF-kappaB p65 and MMP-9 (P(1) = 0.042, P(2) = 0.013; r(1)= 0.67, r(2)= 0.72).

CONCLUSIONOsteopondin espression is closely related to the invasion and metastases of gastric cancer. It may upregulate the expression of metastasis-related molecule MMP-9 by activating NF-kappaB pathway.