FOLH1 and cancer: Since not only chemical and radiochemical stability is the decisive factor for target structures but their ability to attach to the receptors on the surface of the cancer cells as well, we analyzed binding of fluorescent-labeled molecules of BBN/C1-C2 and PSMA-617 with the appropriate receptors on the cell surface, i.e. bombesin receptor for the BBN/C1-C2 molecule and prostate-specific membrane antigen for the PSMA-617 (Figure 5).