Immunohistochemical Expression of Osteopontin in Gastric Cancer

Osteopontin (OPN) is significantly overexpressed in a variety of malignancies. However, little is known concerning the significance of OPN expression in human cancers. Thus, the aim of this study was to determine the relationship between the degree of OPN expression, the proliferative activity of cancer cells, and the clinicopathological findings for surgically resected gastric cancer. We evaluated the immunohistochemical expression of OPN in 85 specimens of cancer. Additionally, we investigated a cancer cell proliferative index using an anti-MIB-1 antibody and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling staining. Levels of OPN expression in gastric cancers were classified into three groups. To compare the relationship between OPN expression and clinicopathological findings, the features of cancer lesions were classified using the TNM Classification of Malignant Tumors, 6th Edition. Immunohistochemical examination of OPN expression in gastric cancer revealed diffuse granular staining in the cytoplasm. High OPN expression was observed in 37 of 85 carcinomas. Strong OPN expression was significantly associated with a low apoptotic index, a high proliferative index, depth of invasion, lymphatic invasion, and venous invasion. Pathologically, intestinal type carcinoma showed strong expression of OPN. These data suggested that OPN may play an important role in the invasiveness and the progressive nature of gastric cancer.