Detection of metastatic breast carcinoma cells by immunofluorescent demonstration of Thomsen-Friedenreich antigen.

The Thomsen-Friedenreich antigen (TF-antigen), known as a precursor of the MN-blood-group system, has been suggested as a tumor-associated antigen of breast adenocarcinoma. In order to evaluate the TF-antigen as a tool in the histochemical detection of micrometastases, cryostat sections of 25 breast biopsies and 30 regionary lymph nodes were investigated. The study used a sensitive method for the fluorescent staining of the determining terminal disaccharide sequence of asialoglycophorin A by application of peanut agglutinin (PNA) and fluoresceinisothiocyanate-labeled F(ab')2 fragments of monospecific anti-PNA from rabbits. PNA binding was observed in 91% of the sections of predominantly ductal mammary carcinomas. In normal tissues and hyperplastic lesions, staining patterns were markedly different from that of malignant breast cells, and were confined to secretory glycoproteins. Lymph nodes, with histologically confirmed metastases of mammary carcinomas, showed specific PNA binding in the cytoplasm of tumor cells in 75% of cases. Even single malignant cells were demonstrable, which were not recognized at first by routine light microscopy. Fluorescent staining of lymph nodes, which were tumor-free in repeated histologic examinations, was confined to clearly diagnosible histiocytes in 3 of 15 cases. A sensitive indirect immunofluorescent technique demonstrating PNA binding is proposed to be of considerable value for the detection of single metastatic adenocarcinoma cells of the human breast.