Similar to our HER2NT mice, Bardeesy et al. reported that the combination of KrasG12D with Smad4 deletion resulted in the rapid development of IPMN, although selective deletion of Smad4 alone in pancreatic epithelial cells showed no distinct phenotype23. The gene discussed is SMAD4; the disease is pancreatic intraductal papillary-mucinous neoplasm.