PECAM1 and neoplasm: Comparison of CD146 staining with that of CD31, a pan‐endothelial marker, showed the concomitant expression of CD146 on the endothelial cells in tumor blood vessels, in accordance with the fact that CD146 could interact with vascular endothelial growth factor receptor 2 on the endothelial cells.31 The immunofluorescent findings corroborated the in vivo imaging data of 89Zr‐Df‐YY146 PET and warranted further translational application of this tracer in melanomas.