Background: There have been many reports that the u-PA system plays an important role in cancer invasion and metastasis. The binding of u-PA to its specific cell-surface receptor, u-PAR, is necessary for the activation of u-PA system. The aim of this study is to evaluate the role and the prognostic value of u-PAR in cancer invasion and metastasis.
Patients and methods: u-PAR expression in 104 breast cancers was investigated immunohistochemically using a monoclonal antibody against u-PAR.
Results: u-PAR expression was mainly observed both on cancer cells and stromal cells. Patients with high u-PAR expression in cancer cells or stromal cells had a high relapse rate compared with patients with low u-PAR expression by the Kaplan-Meier method (p = 0.035 and 0.011, respectively). In uni- and multivariate analysis, u-PAR expression in stromal cells was significantly correlated with relapse (p = 0.017 and 0.043, respectively).
Conclusions: This study has shown that not only cancer cells but also stromal cells have an important roles in breast cancer invasion and metastasis, and that u-PAR expression in cancer cells and stromal cells might be a novel prognostic factor in breast cancer.