Abstract A081: Molecular phenotyping and risk stratification of intraductal papillary mucinous neoplasms

Objective: Morphological subtyping of intraductal papillary mucinous neoplasms of the pancreas (IPMNs) into pancreatobiliary-type, intestinal-type, or gastric-type is a prognostic factor, however, molecular foundations explaining the difference of clinical behaviors are unknown. Our research aimed to elucidate the molecular phenotypes associated with subtypes of IPMNs and establish a risk stratification model. Design: In 171 IPMNs with high-grade dysplasia (HGD) and invasive carcinoma, we analyzed protein expressions of p16, p53, SMAD4, STK11, and β-catenin by immunohistochemistry, and mutations and copy number variations of KRAS and GNAS by droplet digital PCR, and analyzed the association with clinicopathological factors. Results: In HGD components of IPMNs of pancreatobiliary- (n=66), intestinal- (n=70), and gastric-type (n=35), alterations were detected respectively as follows: KRAS mutation; 98%, 62%, and 83% (P