GRPR and breast cancer: In this context, the aim of this research was to prepare and evaluate a novel drug and radiation delivery nanosystem based on the 177Lu-labeled PAMAM dendrimer (DN) loaded with PTX and functionalized on the surface with the Lys1Lys3(DOTA)-bombesin (BN) peptide for specific targeting to gastrin-releasing peptide receptors (GRPr) overexpressed on breast cancer cells.