RESUMO
Twenty-one cases of benign and malignant salivary gland tumors [6 cases of pleomorphic adenoma, 3 cases of carcinoma ex-mixed tumors, 3 cases of adenoid cystic carcinoma, 2 cases of epimyoepithelial carcinoma and 4 of mucoepidermoid carcinoma were screened for anti HLA-DR using monoclonal antibody immunoperoxidase method. The current study showed that benign tumor [pleomorphic adenoma] was negative in reaction, except mild focal reaction in both epithelial and stromal elements. Malignant mixed tumors, adenoid cystic carcinoma as well as low grade mucoepidermoid carcinoma showed moderate reaction. Intermediate and high grade mucoepidermoid carcinoma expressed strong HLA-DR reaction. Such findings suggested that there is a proportional relation between the malignancy and expression of HLA-DR in the epithelial cells