GRPR and neoplasm: Since 68Ga-labeled LW01107, LW01108, LW01110, LW01142 and LW02040 have comparable GRPR binding affinities (Ki = 1.34–3.19 nM), we suspected that the greatly improved tumor uptake for tracers with at least both Tle10 and NMe-His12 substitutions could be mainly due to their improved in vivo stability.