Human gliomas radioimmunoimaging with 131-I BC-2 murine IgG: preliminary report

Ten patients with intracranial malignancies were studied by radioimmunoscintigraphy with I-131 BC-2 MoAb. Sensitivity and specificity of radioimmunoimaging were determined and compared with the results obtained with computed X-ray tomography and magnetic resonance imaging. BC-2 MoAb is a murine IgG1 anti-tenascin, which is not expressed by adult normal brain and has been found in large amount in gliomas and/or cerebral metastases, as well as other human tumors. Gamma-camera images obtained at 1 to 4 days exhibited increasing uptake of BC-2 in eight tumors, with varying degrees of contrast with the surrounding normal brain. Two lesions resulted negative to RIS: a meningioma and an oligodendroglioma. Specific tumor uptake of I-131 BC-2 was determined, by external gamma imaging, and ranged from 0.002 up to 0.007 percent of injected dose. Nonspecific uptake in the tumor was determined injecting 99m-Tc-FO23C5 (an isotype-matched control IgG1) in four patients and it was lower than 0.0001% ID. I-131 BC-2 tumor/nontumor ratios, measured using the geometric mean on digital images, ranged from 3 to 7.5:1. This study demonstrates that the tumor uptake of BC-2 in patients with glioma was due to specific processes.