Radioimmunodiagnosis of human-derived squamous cell carcinoma

Squamous cell carcinomas (SCC) of the head and neck are common and aggressive tumors. A murine IgG 2aK monoclonal antibody (A9) reactive with most SCCs was radiolabeled with I-131 and tested for localization and imaging ability in groups of nude mice bearing SCC tumors derived from two patients with head and neck cancer (UM-SCC-2 and UM-SCC-11B). The mice also received I-125 labeled isotype-matched control antibody UPC-10 for double-label counting. Animals were imaged at multiple time points post-injection and sacrificed 7-10 days later for assessment of the tissue distribution of the radiopharmaceuticals. In general, the tumors were visualized satisfactorily on gamma camera images of both the UM-SCC-2 and UM-SCC-11B tumor-bearing animals. While localization of the A9 antibody was mainly due to antibody specificity in the UM-SCC-2 tumor-bearing animals, there was also a large component of non-specific antibody localization in the UM-SCC-11B bearing animals. This may be due to greater central fluid space and or necrosis in the UM-SCC-11B tumors. This study demonstrates the feasibility of imaging human-derived squamous cell carcinomas with radiolabeled monoclonal antibody A9 and holds forth the possibility of therapy of this radiosensitive tumor in a like manner.