PDAC originates from differentiated acinar cells, in which KRAS mutation alone does not elevate total RAS activity to the levels required for transformation. Acinar-ductal reprogramming occurs when KRAS signaling increases in response to exogenous inflammatory stimuli and/or EGFR agonists; as KRAS activity increases, mutant cells produce endogenous signals that establish a positive feedback loop between KRAS and inflammation. Several genes counteract acinar reprogramming, including Nr5a2, Mist1 and β-catenin, but are themselves inhibited by high levels of KRAS signaling. We hypothesize that acinar reprogramming represents a key step of PDAC initiation, which might be inhibited by anti-inflammatory agents in a chemopreventive setting.