OBJECTIVETo investigate the expression of osteopontin (OPN) splice variant mRNA, including the three isoforms OPN-A, OPN-B, and OPN-C, to explore its correlation with clinicopathologic features in gastric cancer, and to elucidate their role in tumor invasion and distant metastasis of gastric cancer.

METHODSThe expression of OPN-A, OPN-B and OPN-C mRNA were detected by real-time reverse transcriptase-polymerase chain reaction in 66 gastric cancer tissues. The relationship between the expression of OPN-A, OPN-B and OPN-C mRNA and clinicopathologic features of gastric cancer was analyzed.

RESULTSThe expression of OPN-C mRNA in the gastric cancer tissue was 3.21-fold higher than that in peritumoral mucosal tissue, showing a significant difference between them (P < 0.001). OPN-C mRNA expression was correlated with the depth of tumor invasion, tumor diameter, lymph node meatastasis, distant meatastasis and had no correlation with differentiation grades. The low expression of OPN-C mRNA was correlated with long survival benefit (P = 0.03). The expression of OPN-A and OPN-B mRNA had no significant relationship with clinicopathologic features of gastric cancer.

CONCLUSIONSOne of the isoform of osteopontin (OPN) OPN-C mRNA is overexpressed in gastric cancer. The overexpression of OPN-C mRNA may reflect the progression and is associated with the prognosis of gastric cancer. OPN-C mRNA may have value as a prognostic biomarker in gastric cancer. However, the expression of OPN-A and OPN-B are not correlated with the progression and metastasis of gastric cancer.