Protein expression of osteopontin in tumor tissues is an independent prognostic indicator in gastric cancer

Objective: Osteopontin has been shown to facilitate the progression and metastasis of malignancies and to be of prognostic value in several human cancers. In gastric cancer, the protein expression of osteopontin has been found to be correlated with tumor invasion and metastasis, but data on its prognostic value are lacking. The aim of this study was to classify the prognostic significance of osteopontin in gastric cancer. Method: In this retrospective study, 306 tumor tissue samples resected from patients with gastric cancer were investigated by staining with a commercial polyclonal antibody against osteopontin. Results: Positive osteopontin expression (>5% of the cancer cell cytoplasm positive) was found in 132 (43.1%) of 306 stained tumors. High osteopontin expression correlated with deep invasion, lymph node metastasis, distant metastasis and higher TNM stage. Patients with osteopontin-positive expression had poorer overall and disease-free survivals than those with negative expression (p < 0.001 for both). Multivariate analysis revealed osteopontin expression as an independent prognostic indicator of poor disease-free and overall survival in patients with gastric cancer, particularly for survival in TNM stages II (p < 0.05) and III (p < 0.01) patients. Conclusion: Osteopontin protein expression was confirmed as a new independent predictor of tumor recurrence and poor prognosis in patients with gastric cancer. Copyright (c) 2007 S. Karger AG, Basel.