A study on peanut lectin-binding sites in mucoepidermoid tumors of the oral cavity.

Peanut lectin (PNA) is known to bind β-D-Gal (1-3) -Gal NAc which provides an antigenic determination for the T blood group antigen (Tag). Recently, there has been interest in the expression of the Tag in human malignant tumors. We examined 9 mucoepidermoid tumors, 4 normal salivary glands, 3 cases of sialadenitis and 5 epidermoid carcinomas for their ability to express the Tag by staining paraffin sections with FITC conjugated PNA.Consequently, the mucous producing cells of the mucoepidermoid tumors and the mucous acinar cells of sialadenitis showed the expression of the Tag but the fluorescence was never observed in normal salivary glands. Mucous materials, mucous producing cells in the cystic cavity and the epidermoid cell surfaces of the mucoepidermoid tumors and serous acinar cells of normal salivary glands showed the Tag after the tissue sections were pretreated with neuraminidase, but we never observed the intense fluorescence on the epidermoid cell surfaces of the epidermoid carcinomas. In this study, we suspect that the presence of the Tag in mucoepidermoid tumors does not necessarily mean malignancy.