ABSTRACT
This chapter focuses on the distribution and the biochemical characterization of several peptide receptors other than somatostatin in different tumor types, and on the clinical relevance of their pathological assessment on tissue samples as an important tool for the proper diagnosis and therapy of different malignancies. Immuno(cyto)histochemistry is becoming an emerging new diagnostic technique for peptide receptor assessment, especially in the study of large, either prospective or retrospective tumor series, in virtue of its diagnostic accuracy, low cost, and high reproducibility, and high cellular resolution when applied to paraffin-embedded tumor tissues. Cholecystokinin and gastrin exist in different molecular forms, all deriving from prohormones processed to peptides of variable length, but characterized by the same five terminal amino acid sequences at the C-terminus extremity. Neurotensin is a tridecapeptide detectable in the central nervous system and the gastrointestinal tract. Tumor peptide receptors have been extensively mapped by several techniques, which offer different results according to the specific questions to be addressed.
