Intraductal papillary mucinous neoplasm (IPMN) is a pancreatic exocrine tumour characterised by cystic dilatation of the main and/or branch pancreatic ducts; these ducts are lined with a mucin-producing atypical epithelium that often proliferates in a papillary fashion [1]–[3]. The gene discussed is MUC5AC; the disease is pancreatic intraductal papillary-mucinous neoplasm.