Clinical and Genetic Implications of DNA Mismatch Repair Deficiency in Patients With Pancreatic Ductal Adenocarcinoma

Abstract

DNA mismatch repair status is a well-established biomarker in colorectal cancer and is associated with both a favorable prognosis and excellent response to immunotherapy.¹ However, the influence of deficient DNA mismatch repair (dMMR) and microsatellite instability in pancreatic ductal adenocarcinoma (PDAC) remains unknown. The prognosis of PDAC is typically dismal and treatment options are limited, but previous research has suggested that microsatellite instability in resected PDAC specimens may be associated with improved survival.² Because patients with Lynch syndrome harbor germline defects in mismatch repair genes and have significantly elevated lifetime risks of malignant neoplasms, including PDAC,³ we used this unique patient cohort to establish the clinical behavior and outcomes of dMMR PDAC.