GRPR and neoplasm: Several studies have shown that the antagonistic bombesin analogue RM26 (d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2) [31], labelled with different radionuclides such as 68Ga [32,33,34], 111In [24,32], 18F [35], 55/57Co [36], and 177Lu [37] containing different chelators, is a potential targeting agent for in vivo targeting of GRPR-expressing tumours.