A novel biotinylated probe specific for hyaluronate. Its diagnostic value in diffuse malignant mesothelioma

Diffuse malignant mesotheliomas are known to secrete a large amount of hyaluronate, whereas adenocarcinomas produce predominantly neutral mucins. In the present study, we assessed the diagnostic usefulness of a new, highly specific and sensitive hyaluronate binding probe to discriminate between mesotheliomas and adenocarcinomas. We studied 33 mesotheliomas and 37 adenocarcinomas in order to establish specific diagnostic criteria for using the hyaluronate binding probe. Of the adenocarcinomas, only three showed significant positive staining for hyaluronate (8%). By contrast, all the mesotheliomas exhibited positive staining for hyaluronate. Furthermore, the staining reaction was classed as moderate or greater in 26 mesotheliomas (79%), thus suggesting the utility of this probe in the differential diagnosis of malignant mesothelioma versus adenocarcinoma. We conclude that strong cytoplasmic or membranous staining for hyaluronate is highly predictive of malignant mesothelioma. The hyaluronate binding probe should therefore be considered an important adjunct to be used in combination with electron microscopy and immunohistochemistry in the histologic diagnosis of diffuse malignant mesothelioma.