Cathepsin-D and tumor associated antigen DF3 in salivary gland neoplasia. Differential diagnostic and prognostic applications.

Salivary gland tumors pose considerable difficulty in diagnostic and prognostic assessment based on the histopathologic features alone. Cathepsin-D is overexpressed in cancer cells where its concentration in the primary tumor is correlated with increased risk of metastasis. DF3 antigen is a tumor associated glycoprotein that is specific for malignant cells of glandular origin. We examined the distribution patterns of cathepsin-D and DF3 antigens in benign (n = 11) and malignant (n = 44) salivary gland tumors of various histologic types. The frequency of cathepsin-D expression is significantly increased (p < 0.001) in salivary gland carcinomas compared to benign mixed tumors (BMT). High levels of cathepsin-D expression was frequent in carcinomas ex BMT, mucoepidermoid carcinomas, poorly differentiated adenocarcinomas-NOS and adenoid cystic carcinomas (ACC). Acinic cell carcinomas and polymorphous low-grade adenocarcinomas were mostly negative. Intense cytoplasmic staining for DF3 antigen was noted in the tumor cells of mucoepidermoid carcinomas, carcinomas ex BMT and poorly differentiated adenocarcinomas-NOS whereas other types of salivary gland carcinomas exhibited either negative or only focal membrane staining. The noted differences in the reactive patterns of cathepsin-D and DF3 antigen among various histologic types of salivary gland carcinomas may have differential diagnostic and prognostic applications.