Abstract Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy and is largely refractory to available treatments with heterogenous chemotherapeutic response in subsets of patients. Identifying key pathways associated with disease aggressiveness and therapeutic resistance may characterize candidate targets to improve patient outcome. We used a strategy of examining the molecular subset of PDAC patients with worst survival to understand the underlying mechanisms of disease progression and to identify candidate molecular targets with potential therapeutic significance. Non-negative matrix factorization (NMF) clustering using gene expression profile revealed three patient subsets. A 142-gene signature specific to the subset with the worst patient survival predicted prognosis and stratified patients in two clusters in a test (N=126) and validation (N=176) cohorts with significantly different survival. Gene-network and pathway analysis of the 142-gene signature revealed dysregulation of hepatocyte nuclear factor 1-B (HNF1B)/Clusterin (CLU) axis in the highly aggressive patient subset. HNF1B positively regulated CLU and a lower expression of HNF1B and CLU was associated with poor patient survival. Mechanistic and functional analyses revealed that CLU inhibits proliferation, migration, invasion, and 3D spheroid growth and epithelial-to-mesenchymal transition in pancreatic cancer cells. Furthermore, CLU enhanced sensitivity of pancreatic cancer cells, representing the aggressive patient subset, to the chemotherapeutic drug gemcitabine. Taken together, targeting HNF1B/CLU axis may attenuate disease progression with potential therapeutic implication in a subset of pancreatic cancer. Citation Format: Shouhui Yang, Wei Tang, Peijun He, Limin Wang, Jochen Gaedcke, B. Michael Ghadim, Philipp Ströbel, Azadeh Azizian, Matthias M. Gaida, Frank Bergmann, H. Richard Alexander, Nader Hanna, S. Perwez Hussain. Dysregulation of HNF1B/Clusterin axis enhances disease progression in a highly aggressive subset of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C61.