Pancreatic cyst formation is dynamic and accompanied by increased cell proliferation. (A) Time-lapse imaging of pancreatic cyst development. Serial images over 72 h of an E16.5 Lkb1^MG/MG explant expressing Pdx1-GFP treated with 1 µM 1NMPP1. Cyst formation begins as a dilatation of the distal ductal compartment. Adjacent acinar structures can remain intact (white arrows) or can be seen coalescing with the wall of the cyst (yellow arrows). Bar, 100 µm. (B) Pancreatic cysts exhibit increased cell proliferation. Increased EdU (red) incorporation in E-cadherin (green)–positive cells forming a cyst in an Lkb1^MG/MG explant (bottom) compared with an Lkb1^WT/WT explant (top). Bars, 50 µm. (C) FACS analysis of pancreatic explants showing increase in EdU incorporation in the EpCAM-positive cells associated with Lkb1 inhibition. The data shown is from a single representative experiment out of five independent experiments.