Expression of ras-P21 and ras gene alteration in pleomorphic adenomas

The expression of ras-P21 protein and gene alteration of the K-ras gene were examined in 12 cases of pleomorphic adenoma of the salivary gland. The tumor cells in all 12 cases were strongly stained for ras-P21 protein by the indirect immunoperoxidase method, suggesting the enhanced expression of ras-P21 protein in pleomorphic adenomas. Analysis of the PCR products for the K-ras gene by temperature-gradient gel electrophoresis (TGGE) revealed that gene alterations such as point mutations occurred in 4 out of 12 pleomorphic adenoma tissues examined.