Another interesting idea is to combine the bombesin binding motif with another peptide, creating heteromultimeric ligands, which can improve the construct targeting ability (e.g., RGD sequence against integrin αυβ3 [32,33], prostate-specific membrane antigen (PSMA)-inhibiting peptides for targeting of prostate cancer) or cellular penetration (e.g., Tat(49–57), HIV-1-derived sequence [34,35]). This evidence concerns the gene GRP and prostate cancer.