TSPO and neoplasm: To validate our approach, we 1) compared in vivo measurements to ex vivo autoradiography and histology; 2) evaluated the specificity of tracer binding (in vivo displacement procedure); and 3) confirmed the presence of TSPO mRNA by means of in situ hybridization, as well as TSPO protein levels produced by the tumor by means of immunohistochemistry and western blotting, respectively.