Immunohistochemical evaluation with Ki-67: an application to salivary gland tumours.

Using Ki-67, a monoclonal antibody, the proliferating capacity of 15 salivary gland tumours, including nine pleomorphic adenomas, four adenoid cystic carcinomas, one mucoepidermoid carcinoma and one acinic cell carcinoma was determined immunohistochemically, using normal salivary gland tissue as a control. The frequency of Ki-67 positive cells was 4.7 percent in the normal salivary gland and one percent in pleomorphic adenomas, whereas the average frequency in malignant tumours was 18.3 percent. Among adenoid cystic carcinomas, the frequency was related to the morphological type; the solid sub-type had the highest frequency of Ki-67-positive cells. As this sub-type is recognized as the most aggressive of these tumours, this technique has the potential of providing an early indication of the clinical behaviour of a tumour.