Preliminary study on radioimmunodiagnosis of experimental tumor models using technetium-99m-labeled anti-C-erbB-2 monoclonal antibody.

Aims and background: One of the great challenges of oncology is to improve methods for early tumor detection. Diagnosis of premalignant lesions and early stage primary tumors is crucial for the success of cancer therapy and increased survival rates. Growth factor receptors localized to the cell membrane play a vital role in cancer. Monoclonal antibodies labeled with radioisotopes have been used extensively for radioimmunodiagnosis and radioimmunotherapy of various malignancies. A preliminary study on immunoscintigraphy was carried out on animal tumor models using 9 9 m Tc-labeled monoclonal antibody CIBCgp185 generated against the C-erbB-2 oncoprotein with a view to develop technologies for in vivo radioimmunodetection and localization of human breast cancer. Methods: Mammary tumor xenografts induced using BT474 cells, a breast carcinoma cell line showing overexpression of C-erbB-2, were used for immunoscintigraphic studies. Results: Scintigrams showed high radiolabel uptake by the tumor tissue of the mice belonging to the experimental group, whereas in control animals no radiolabel uptake was visualized. Biodistribution studies correlated well with scintiscans Conclusions: The results indicate the potential application of this monoclonal antibody for in vivo diagnosis of occult malignancies of tumors with overexpression of C-erbB-2.