Expression of protease activating receptor-2 (PAR-2) is positively correlated with the recurrence of non-muscle invasive bladder cancer: an immunohistochemical analysis
Kozue Nakahara,1 Koji Yamasaki,1 Takahiro Nagai,1 Masato Fujii,1 Takahiro Akioka,1 Hiroki Takamori,1 Naoki Terada,1 Shoichiro Mukai,1 Yuichiro Sato,2 Toshiyuki Kamoto11Department of Urology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan; 2Section of Diagnostic Pathology, Faculty of Medicine, University of Miyazaki, Miyazaki, JapanBackground: Matriptase, which is a Type II transmembrane serine protease, has the potential to activate several growth factors, including pro-hepatocyte growth factor (HGF). A G protein-coupled transmembrane cell-surface receptor and a protease-activated receptor 2 (PAR-2) are also required for activation by matriptase. Activation of PAR-2 has been reported to induce the progression of various cancers. In a previous study, we evaluated the correlation between upregulation of MET phosphorylation with high matriptase expression and worse prognosis in patients with muscle invasive bladder cancer; however, expression of PAR-2, matriptase and MET in non-muscle invasive bladder cancer (NMIBC) has not been evaluated.Materials and methods: We retrospectively analyzed the expression of PAR-2, matriptase and MET using 55 paraffin-embedded specimens obtained from patients with NMIBC by immunohistochemistry.Results: MET was significantly expressed in high-grade urothelial carcinoma (UC) and pathological T1 cancers. High expression of PAR-2 was significantly associated with a worse recurrence rate in NMIBC. In subgroup analysis, the expression of PAR-2 was also correlated with high recurrence rate in low-grade UC. In addition, expression of matriptase tended to correlate with worse recurrence rate in high-grade UC.Conclusion: Increased expression of PAR-2 was significantly correlated with worse recurrence rate in patients with NMIBC. In addition, expression of matriptase also indicated a tendency toward recurrence in high-grade UC, suggesting an important role of matriptase-induced PAR-2 activation in NMIBC.Keywords: PAR-2, matriptase, MET, NMIB