Molecular Characterization and Pathogenesis of Intraductal Papillary Mucinous Neoplasms of the Pancreas.

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are noninvasive neoplasms which occur in the main pancreatic duct or its major branches. IPMNs have an important meaning in the clinic and in research since they represent around 20% of all resected pancreatic neoplasms. Morphologically, branch duct, main duct and mixed-type IPMNs can be distinguished. Histologically, they can be divided into gastric, intestinal, pancreatobiliary and oncocytic type. There are different mutations in genes such as KRAS, GNAS, RNF43 and p53. The expression of miRNAs is specific to IPMNs; altogether, 14 miRNAs have been identified so far which are differently expressed in all IPMNs in contrast to normal pancreatic tissue. It has also been observed that methylation levels can be altered in IPMNs. This review summarizes the molecular characteristics of IPMNs of the pancreas and presents currently known markers.