In this study, we use radionuclide molecular imaging, for the first time, to compare the trafficking and biodistribution of two engineered homologous IgG and IgE antibodies6,7 targeting a tumor-associated antigen, CSPG4 (chondroitin sulfate proteoglycan 4): anti-CSPG4 IgG and anti-CSPG4 IgE. Here, CSPG4 is linked to neoplasm.