Breast carcinoma detection with a combination of radiolabeled monoclonal antibodies. Promising results from immunohistochemistry studies.

Background: Recent studies have demonstrated that the use of radiolabeled monoclonal antibodies (MoAbs) directed against tumor-associated antigens could help in the recognition of primary tumors, their extent, and their metastases by external scintigraphy (used preoperatively) or by hand-held gamma-detecting probe (GDP) (used intraoperatively).
Methods: The authors evaluated carcinoembryonic antigen (CEA), c-erb B-2 protein, and TAG-72 expression in 100 cases of breast carcinoma using F023C5 (anti-CEA), B72.3, and anti-c-erb B-2 protein MoAbs that were previously investigated for their usefulness in radioimmunoguided surgery and external scintigraphy. The goal of this study was to examine the biodistribution of each antibody in primary, multifocal, and metastatic lesions to evaluate the suitability of their simultaneous use in GDP and external scintigraphy.
Results: Results showed immunoreactivity for c-erb B-2 protein in 39 of 99 cases, for B72.3 in 41 of 100 cases, and for CEA in 15 of 100 cases. Multifocal lesions demonstrated positivity for c-erb B-2 protein in 37.4% of cases (6 of 16), for B72.3 in 68.8% of cases (11 of 16), and for CEA in 6.2% of cases (1 of 16). In lymph node metastases, immunoreactivity was found for c-erb B-2 protein in 36.4% of cases (12 of 33), for B72.3 in 63.7% of cases (21 of 33), and for CEA in 24.3% of cases (8 of 33). When the authors considered the immunoreactivity of all three MoAbs, the percentage of positive cases they observed was 60% in primary tumors (60 cases), 78% in lymph node metastases, and 81.2% in multifocal lesions.
Conclusions: These results suggest that in vivo tumor radioimmunodetection could be improved by the use of more antibodies directed against different tumor-associated antigens.