MUC5AC and pancreatic intraductal papillary-mucinous neoplasm: PDAC evolves from early precursor lesions, including pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasia (MCN), a highly invasive neosplasms characterized by an ovarian-type stroma and a mucin-producing epithelium (Hruban et al., 2007; Distler et al., 2014; Pusateri and Krishna, 2018).