MUC4 and keratoconus: Subsequently, to explore the potential of the cooperative effect between KrasG12D/+ and Muc4 overexpression, specifically the oncogenic Muc4/X, in inducing Activin A secretion in pancreatic cells, we isolated double EpCAM/Muc4‐positive pancreatic cells and EpCAM‐positive/Muc4‐negative pancreatic cells from 4‐week‐old KC mice.