Scintigraphic detection of xenografted tumors producing human basic fibroblast growth factor

A murine monoclonal antibody 3H3 recognizes the basic fibroblast growth factor (FGF) and inhibits the growth of human glioblastoma cells both in vitro and in vivo. We studied the potential of a scintigraphic technique using the 3H3 antibody to detect tumors that produce basic FGF.¹²⁵I- and¹¹¹In-labeled 3H3 bound to U87MG human glioblastoma cells in vitro. U87MG cells were inoculated subcutaneously into nude mice. After development of the tumor, radiolabeled 3H3 was injected into the subcutaneous space surrounding the tumor. A high level of radioactivity from 3H3 was retained at the tumor, whereas an irrelevant antibody cleared rapidly from the injected site. Radiolabeled 3H3 was not retained in tumors that did not produce basic FGF. Scintigraphic detection of tumors expressing basic FGF would be valuable for the therapeutic application of the antibody.