High-level expression of periostin is significantly correlated with tumor angiogenesis in prostate cancer

Periostin (PN), originally named osteoblast-specific factor-2 (OSF-2), is a multifunctional glycoprotein which can significantly promote EMT (epithelial-mesenchymal transition). Recently, many studies have shown that high-level expression of PN is correlated significantly with tumor angiogenesis and prognosis in many kinds of human cancer. In previous experiments, we screened PN from prostate cancer through iTRAQ technology and found that PN affects occurrence and development of prostate cancer (PCa). However, whether and how periostin expression influences tumor angiogenesis in prostate cancer remains unknown. Our study aimed to examine expression of PN in patients with PCa and explored the relationship of PN expression with clinicopathologic factors and tumor angiogenesis. Immunohistochemistry was performed to determine expression of PN in PCa and benign prostate hyperplasia (BPH). Vascular endothelial growth factor (VEGF) and CD31 (used to mark tumor angiogenesis) were also examined in tissues from the PCa patients and hyperplasia patients mentioned above. The results showed that PN expression was significantly (P