Objective: Osteopontin (OPN) has been found to be valuable in diagnosis and predicting the prognosis of a variety of malignancies. The aims of the present study are to evaluate the usefulness of plasma OPN level for predicting gastric cancer development, invasion and survival.
Patients and methods: One hundred and thirty two gastric cancer patients and 93 healthy controls were enrolled. Real-time quantitative reverse-transcription polymerase chain reaction and immunohistochemical staining were used to detect OPN expression in gastric cancer tissues. Plasma levels of OPN were measured by enzyme-linked immunosorbent assay. Plasma OPN levels were compared with gastric cancer development, clinicopathological features and outcomes.
Results: Expression of OPN mRNA was significantly higher in gastric cancer tissues compared with non-tumour tissues. Most OPN immunoactivity was localised to cancer cells. The median plasma OPN level was significantly higher in patients than in controls (p<0.0001), and significantly higher in patients with advanced stages, serosal invasion, lymph node metastasis, lymphatic invasion, venous invasion and liver metastasis. Logistic regression showed that high plasma OPN level (greater than 67.3 ng/ml) is significantly associated with advanced stages, serosal invasion, lymph node metastasis, lymphatic invasion, venous invasion and liver metastasis. Plasma OPN level demonstrated significant association with patient survival (p<0.0001), especially in the subgroups with invasive phenotypes. On Cox multivariate analysis, elevated plasma OPN level was an independent risk factor for poor survival (p<0.0001).
Conclusions: Elevated plasma OPN level is significantly associated with gastric cancer development, invasive phenotypes and survival. Plasma OPN level may have potential usefulness as a diagnostic and prognostic factor for gastric cancer.