Loss of maspin is a negative prognostic factor for invasion and metastasis in oral squamous cell carcinoma

Objective: Maspin, a 42-kDa protein, belongs to the serpin family of protease inhibitors and is known to have tumor-suppressor function. In this study, we investigated the interrelationship between clinicopathologic findings and maspin expression in oral squamous cell carcinoma (OSCC). Methods: Using immunohistochemical techniques to examine the expression levels of maspin in OSCC, maspin expression in OSCC was detected in 46 (64.8%) of 71 cases. We also compared the clonicopathologic features of OSCC cases with maspin expression levels. Moreover, we examined expression of maspin in eight cell lines derived from OSCC using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. Results: There was a significant correlation between decreased maspin expression and T-category (P < 0.01), lymph metastasis (P < 0.0001), and mode of invasion (P < 0.0001). Patients with positive maspin expression had a significantly better prognosis (P < 0.001). Lower expression of maspin was also seen in cell lines derived from grade 4D, which shows stronger invasive potential than other grades of OSCC. Conclusion: Maspin may be a useful marker to identify the potential for progression in OSCC.