Increased osteopontin expression in endometrial carcinoma is associated with better survival outcome.

Objectives: Osteopontin (OPN) is a key extracellular matrix protein that is involved in cancer progression. The aim of the current study is to investigate the relation of OPN immunostaining in endometrial carcinoma with clinicopathological parameters. Material and methods: Archival 71 endometrial carcinomas and 30 non-neoplastic endometrial tissues were obtained from the Department of Pathology at King Abdulaziz University Jeddah, Saudi Arabia. Tissue microarrays were constructed. Tissue sections were stained using anti-human OPN monoclonal antibody. Immunostaining results were recorded and analysed. Results: In non-neoplastic endometrial tissues, high (increased) OPN immunostaining was observed in 100%. In endometrial carcinoma, high (increased) OPN immunostaining was seen in 64.8% of cases. High (increased) OPN immunostaining was more frequent in non-neoplastic tissues than in endometrial carcinoma (p < 0.001). OPN immunostaining showed no association with histological type, FIGO tumour grade, tumour size, myometrial invasion, lymphovascular invasion, surgical resection margin or lymph node metastasis. On the other hand, high (increased) OPN immunostaining was associated with better overall survival [Log Rank (Mantel-Cox) = 4.385, p = 0.003]. Conclusions: In endometrial carcinoma, immunohistochemical staining of OPN could be a helpful tool in the prediction survival pattern. OPN immunostaining showed no association with most clinicopathological features. Further investigations both clinical and molecular are needed to explore the downstream of OPN in endometrial carcinoma.