Cytoplasmic-only Expression of Maspin Predicts Poor Prognosis in Patients With Oral Squamous Cell Carcinoma

Background/Aim: Maspin has tumor-suppressor functions; however, its prognostic value in patients with oral squamous cell carcinoma (OSCC) remains unknown. We aimed to assess the prognostic importance of the subcellular localization of maspin in patients with OSCC. Patients and Methods: Eighty resected specimens were analyzed by immunohistochemistry. Cytoplasmic-only expression observed in >10% of the tumor was defined as maspin-positive. Results: The maspin-positive status (25%) was significantly associated with a higher recurrence rate and shorter disease-free survival (DFS). Cox's multivariate analysis showed that maspin-positive status was an independent factor for shorter DFS. All OSCC cell lines (HSC2, HSC3, HSC4, Ca9-22 and SAS) showed maspin protein localization to both the cytoplasm and nucleus using western blot analysis. In HSC4 cells, cell invasion was significantly increased in response to maspin knockdown. Conclusion: Cytoplasmic-only expression of maspin could be an independent poor prognostic factor for patients with OSCC.