[Mammary carcinoma in female dogs: a new routine diagnosis by the detection of occult micrometastases in the regional lymph nodes].

It was here to find an antibody staining either the epithelial tissues of the canine mammary or the tumor cell embolisms and metastases in their regional lymph nodes. 77 formalin-fixed and paraffin-embedded mammary carcinomas and their regional lymph nodes were examined by immunocytochemical technique, all of them free of metastases in routine haematoxylin and eosin (HE) staining. To compare the two methods two serial sections were cut of three parts of the lymph nodes. One was stained with the antibody AE1, which reacts with cytokeratin subtype I/A, in the SEQUENZA by APAAP-method, the other with HE. In 84.4% of all 77 lymph nodes tumour cell embolism and/or micrometastases were detected. Comparing the two methods we found that in HE-staining it was only possible to detect two thirds of all micrometastases containing more than 50 tumor cells. Smaller micrometastases were suspicious in a few cases, the majority could not be detected at all.