ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expression of osteopontin mRNA and its correlation with clinicopathologic features of gastric cancer and elucidate its role in tumor invasion and distant metastasis.</p><p><b>METHODS</b>The expression of OPN mRNA was detected by semi-quantitive RT-PCR. The relationship between the relative content of OPN mRNA and clinicopathologic features of gastric cancer was analyzed.</p><p><b>RESULTS</b>In 66 cancer tissue samples, a 330 bp band was detected in 50 cases, the positive rate of OPN mRNA expression was 75.8% (50/66). The expression in all 20 cases of normal gastric mucosa was negative. The expression was associated with the depth of tumor invasion, diameter, lymph node metastasis and but had no correlation with differentiation grades. The 66 patients were followed up for 10 approximately 27 months (mean 16 months). The OPN mRNA expression positive group (50 cases) had recurrence in 15 patients and the negative group (16 cases) had only 1 case with recurrence (P = 0.05); 10 patients died in OPN mRNA expression positive group but no patient died in OPN staining negative group (P = 0.05).</p><p><b>CONCLUSION</b>OPN mRNA is over-expressed in gastric cancer. It reflects the progression of disease and association with poor prognosis of gastric cancer. OPN may play an important role in the process of distant metastasis in gastric cancer.</p>