P53 and Ki-67 antigen expression in small oral biopsy specimens of salivary gland tumors.

ABSTRACT

OBJECTIVE: To investigate the possibility that various salivary gland tumors that look histologically similar could express p53 oncoprotein and Ki-67 proliferation antigen differentially and possibly aid in distinguishing benign from malignant lesions. STUDY DESIGN: Intraoral paraffin-embedded biopsy specimens of salivary gland tumors were used. Thirty-eight pleomorphic adenomas, 17 adenoid cystic carcinomas, 23 monomorphic adenomas, and 17 polymorphous low-grade adenocarcinomas were stained with p53 and Ki-67 antibodies by using an immunoperoxidase detection system. Each case was evaluated in terms of staining intensity and percentage of cells staining. RESULTS: Ki-67 and p53 antigens are expressed in generally low levels in the histologically well-differentiated salivary tumors that were studied here, both benign and malignant. Only 1 solid-type adenoid cystic carcinoma showed a high percentage of cells expressing p53. CONCLUSIONS: The histologically well-differentiated salivary tumors studied do not show differential expression of p53 and Ki-67, in spite of their differing courses of biologic behavior. These antibodies should not be relied on to distinguish benign from malignant lesions of the salivary glands; however, they might be markers for those lesions that are dedifferentiating histologically and, therefore, might be displaying more aggressive behavior.