The presence of CEA in parotid gland tumours was studied by immunohistochemical methods. 52 cases were analysed. 7 of 8 adenocarcinomas, 3 of 5 cystadenocarcinomas, 3 of 4 adenoid cystic carcinomas and all 3 salivary duct carcinomas were positive for CEA. 5 of 8 squamous cell carcinomas and 9 of 21 carcinomas in a pleomorphic adenoma were also positive for CEA. The anaplastic carcinomas were negative. The distribution pattern of the presence of CEA in the carcinomatous and the adjacent normal or inflamed tissue was analysed. The results are discussed with regard to their histogenetic and diagnostic implications.

In a collection of parotid gland tumors the presenee of different antigens was studied by immuno-histoehemical methods. The series was eomposed of different tumors: adeno-and eystadenoeareinomas, adenoid-eystic carcinomas, salivary duct carcinomas, mucoepidermoid tumors, squamous cell carcinomas and anaplastie carcinomas.The following substances were studied: 1. Substances normally present in salivary glands like lysozyme and laetoferrin. 2. Oncofetal antigens: earcinoembryonie anligen (CEA) and alpha-fetoprotein (AFP). 3. Different elasses of intermediate-sized filaments: prekeratin and vimentin. The presenee of laetoferrin and careinoembryonic antigen could be demonstrated in the glandular differentiated tumors, whereas the squamous cell eareinomas, although CEA positive, were laetoferrin negative. The anaplastie carcinomas were negative for laetoferrin and CEA. Lysozyme and AFP could not be demonstrated in the tumors of our material. Mucoepidermoid tumors and squamous cell carcinomas were clearly positive for prekeratin filaments whereas the stromal part showed vimentin filaments in the eytoplasm of fibroblasts. These antigens provide a useful tool lo distinguish between the epithelial and mesenchymal tumors.

Lactoferrin and lysozyme, parts of the non-specific defense system, were studied in normal and diseased parotid glands, using the immunohistochemical PAP-method. 31 normal and inflamed glands were investigated. The presence of lactoferrin and lysozyme was demonstrated in the acinar cells and some duct cells. The amount of these substances was increased in obstructive parotitis. The 52 carcinomas showed a distinct distribution pattern for lactoferrin (positive cases: adenocarcinomas 5 of 8; cystadenocarcinoma: 3 of 5; adenoid cystic carcinomas 2 of 4; salivary duct carcinomas 2 of 3). Some of the carcinomas in pleomorphic adenomas were positive for lactoferrin. Squamous cell carcinomas and anaplastic carcinomas were constantly negative. All carcinomas were negative for lysozyme. These observations are discussed with respect to their physiological and pathological significance.

Carcinoembryonic antigen (CEA) was analysed in the human parotid gland. Specimens of 31 normal and inflamed parotid glands were studied by the indirect immunoperoxidase technique. The presence of CEA could be demonstrated at the border of the acinar cells and the intercalated duct cells as well as in the undifferentiated duct cells as observed in chronic obstructive parotitis. These observations may explain the presence of CEA in normal human saliva and may provide a new basis for histogenetic interpretation of pathological lesions of the parotid gland, especially of the tumors of the salivary gland tissue.