DPP4 and diabetes mellitus: APC: Advanced pancreatic cancer, DFS: disease-free survival, DM: diabetes mellitus, DPP4: dipeptidyl peptidases-4, DSS: disease-specific survival, N: no, NA: not available, NR: not reported, OS: overall survival, PC: pancreatic cancer, PDAC: pancreatic adenocarcinoma, PFS: progression-free survival, RCT: randomized controlled trial, TZD: thiazolidinediones, Y: yes.