SYNTHESIS OF ELASTIN BY PLEOMORPHIC ADENOMAS

Previous morphologic and histochemical studies have documented extrace llular elastin and elastic fibers within the matrix of pleomorphic ade nomas of the salivary glands, By morphologic criteria, the elastin app eared to be synthesized by the tumor rather than being a consequence o f stroma produced in response to the tumor cells. To examine this issu e, nine pleomorphic adenomas were studied by immunohistochemistry and in situ hybridization with tropoelastin-specific antibodies and comple mentary DNAs. Corroborating the previous morphologic studies, immunohi stochemistry demonstrated abundant extracellular elastin within the ma trix of pleomorphic adenomas. Additionally, both immunohistochemistry and in situ hybridization demonstrated continued synthesis of tropoela stin by the neoplastic cells. Tropoelastin production was seen in neop lastic cells with all morphologies.