Dipeptidyl peptidase IV (DPPIV), also known as adenosine deaminase complexing protein 2 or CD26, is an antigenic enzyme expressed on the surface of most cell types and is associated with immune regulation, signal transduction and apoptosis. Animal studies suggest its pathogenetic role in development of fibrosis of various organs, such as liver and kidney. DPPIV plays an important role in tumor biology, and is useful as a marker for various cancers, with its levels either on the cell surface or in the serum increased in some neoplasms and decreased in others. A new coronavirus related to SARS, named Middle East respiratory syndrome coronavirus, has been found to bind to DPPIV. DPPIV is found on the surface of cells in the airways (such as the lungs) and kidneys. Scientists may be able to use this to their advantage by blocking the virus’s entry into the cell.