Dipeptidyl peptidase-IV and related molecules: markers of malignancy?

BACKGROUND: The dipeptidyl peptidase-IV (DPP-IV) family has outgrown its humble origins as a simple enzymatic activity cleaving dipeptides from peptides with an accessible N-terminal penultimate proline with no clear role in metabolism. It is now understood to play a critical role in regulating signaling capacity of chemokines, neuropeptides and other extracellular messengers in addition to playing direct roles by means of non-enzymatic interactions to regulate the local extracellular proliferative environment. Consequently, examination of DPP-IV family representation and activity in immune and oncogenic processes has become a major focus. OBJECTIVES: To review the evidence for DPP-IV family members as markers of malignancy. METHODS: Overview of published data. RESULTS/CONCLUSION: The DPP-IV family, which is probably linked directly to the pathogenesis of cancer, holds significant promise for exploitation in the diagnostic arena.