Evaluation of the resulting [18F]FBz-DBCO-peptide in mice bearing MDA-MB-231 (TGase 2 +) or MCF-7 (TGase 2 −) tumors revealed that a radiotracer accumulation at the tumor site was not observed for both models, which would have been expected to occur upon TGase 2-catalzyed incorporation of the radiotracer into cellular proteins. Here, TGM2 is linked to neoplasm.