Bombesin receptors as potential targets for anticancer drug delivery and imaging.

The biggest challenge in delivering anticancer agents is the ability to direct these molecules specifically to cancer cells. With this in mind, modern research is focussing on improving the precision of cancer drug delivery by incorporating a ligand that has the ability to specifically recognize cancer cells. Peptides are emerging as a new tool in drug and gene delivery. Peptide-drug conjugates, peptide-modified drug delivery systems, and peptide-coupled imaging agents have been shown to increase on-site delivery. This has allowed better tumor mass contouring in imaging and increased therapeutic efficacy of chemotherapies, reducing adverse effects. Benefits of peptide ligands include their small size, easy and affordable production, high specificity and remarkable flexibility regarding their sequence and conjugation possibilities. Bombesin (Bn) receptors have shown great promise for tumor targeting due to their increased expression in a variety of human cancers, including prostate, breast, small cell lung, and pancreatic cells. This review discusses the overexpression of Bn receptors in different cancers and various approaches to target these receptors for therapeutic and diagnostic interventions in human malignancies.