Comprehensive Analysis of Molecular Biologic Characteristics of Pancreatic Ductal Adenocarcinoma Concomitant with Intraductal Papillary Mucinous Neoplasm.

Background: Pancreatic ductal adenocarcinoma (PDAC) concomitant with intraductal papillary mucinous neoplasm (IPMN) is defined as PDAC occurring apart from IPMN. This study comprehensively investigated the molecular biologic characteristics of PDAC concomitant with IPMN in major genetic alterations, tumor microenvironment, and prognosis by contrast with those of conventional PDAC.

Methods: The study retrospectively reviewed the data of 158 surgically resected PDAC patients. The driver gene alteration status (KRAS, TP53, CDKN2A, SMAD4, and GNAS) together with the immune and fibrotic status in tumor was evaluated. The prognosis of PDAC concomitant with IPMN and that of conventional PDAC also were compared.

Results: No statistically significant difference was found between PDAC concomitant with IPMN and conventional PDAC in the alteration frequency analysis of the major driver genes and the immune and fibrotic status in the tumor microenvironment. Overall survival and disease-free survival between patients who had PDAC concomitant with IPMN and those who had conventional PDAC did not show statistically significant differences in propensity-matched subjects. Furthermore, the co-existence of IPMN was not a poor prognostic factor in the multivariable-adjusted Cox proportional hazards model (hazard ratio, 0.95; 95 % confidence interval, 0.51-1.78).

Conclusions: In this study, PDAC concomitant with IPMN had tumor characteristics similar to those of conventional PDAC in terms of the major driver gene alterations, tumor microenvironment, and prognosis.