After blocking with excess ZJ24 in adjacent slices within the same tumor sample, we detected no PSMA-1-Alexa488 signal (second row) while the CD31 signal remains largely unchanged Fig. 2B. This indicates specificity of PSMA-1-Alexa488 towards PSMA within the neovasculature as well as confirming the expression of PSMA in these tissues. Here, PECAM1 is linked to neoplasm.