ERBB2 and neoplasm: We evaluated the penetration and distribution of 89Zr-DFO-scFv-PEG-Cy5-C’ dots within ex vivo tumor tissue specimens harvested from all three groups at 72 h p.i. (Fig. 5) by widefield fluorescence microscopy, immunohistochemical staining for HER2 expression, H&E staining, autoradiography, and confocal microscopy of tumor tissue specimens.