Loss of Maspin expression is a negative prognostic factor in common salivary gland tumors

Maspin, a 42kDa protein, belongs to the serine protease inhibitor (serpin) family and is suggested to have inhibitory effects on tumor-induced angiogenesis, tumor cell motility, invasion and metastasis and influences prognosis of tumor patients. The aim of the study was to analyze Maspin expression in salivary gland cancer as well as its prognostic impact on survival in comparison to clinical parameters. Immunohistochemical staining was carried out in 73 cases of salivary gland malignancies. High proportions of Maspin expression were observed in adenoid cystic carcinomas, mucoepidermoid carcinomas and carcinomas ex pleomorphic adenoma, low proportions were seen in salivary duct carcinomas. Acinic cell carcinomas did not show any Maspin expression. Analysis of the prognostic impact of Maspin expression was restricted to salivary gland carcinoma types of intermediate malignancy grade (adenoid cystic carcinoma, mucoepidermoid carcinoma and carcinoma ex pleomorphic adenoma). For these tumors, univariate analyses revealed that T-stage (p=0.025), age70 (p=0.0065), loss of Maspin (p=0.0016) and presence of residual tumor (p<0.001) correlated with poor prognosis. In multivariate analysis age70 (p=0.005) and loss of Maspin (p=0.036) were significant prognostic factors. Moreover, negative Maspin staining was associated with lymph node metastasis and residual tumor. According to these findings, Maspin might be useful as a new prognostic marker in adenoid cystic carcinoma and in salivary gland carcinomas with intermediate grade of malignancy where grading systems are still under debate.