PECAM1 and neoplasm: Autoradiographic examination and CD31 immunofluorescence staining of the tumor microvessels with the same whole-tumor sections revealed well-matched intratumoral localization between 64Cu-cyclam-RAFT-c(-RGDfK-)4 and microvessels in both the vehicle (Fig. 4c, d) and TSU-68-treated tumors (Fig. 4e, f).