Immunocytochemical demonstration of intermediate filament proteins, S-100 protein and CEA in apocrine sweat glands and apocrine gland derived lesions of the dog.

The presence of carcinoembryonic antigen (CEA), intermediate filament proteins and S-100 protein in normal and pathological canine apocrine sweat glands was investigated, using a standard immunoperoxidase technique. The normal apocrine sweat glands showed a constant immunoreactivity in all the cases studied. The cells of the acini and of the ducts only reacted with the antikeratin antibody. The myoepithelial cells reacted positively with the antisera antikeratin and anti protein S-100. Epithelial cells of apocrine cysts, sweat gland adenomas and sweat gland carcinomas showed the same immunoreaction than normal apocrine cells. Proliferating myoepithelial cells were also positive for vimentin. In two out of three adenocarcinomas a positive reaction with the anti CEA could be detected in the glandular cells. This can be due to the presence in glandular cells of CEA or of Nonspecific Crossreacting Antigen (NCA). These findings indicate that demonstration of keratin is a useful aid in the detection of apocrine gland derived lesions in the dog. Similarly, S-100 protein is a marker for myoepithelial cells. Further research is necessary to investigate the expression of CEA in canine tumours.