In vitro autoradiography with Y1R-positive MCF-7 tumor tissue slices indicated a high specific binding of the 18F-labeled glycopeptide, when binding was reduced by 95% ([Pra4,F7,P34]NPY) and by 86% (BIBP3226, Y1R antagonist) in competitive binding studies. The gene discussed is NPY; the disease is neoplasm.