IL4 and pancreatic intraductal papillary-mucinous neoplasm: One possible mechanism of the malignant evolution of IPMN, in light of our findings and existing literature, is that the expression of CD55, promoted by the immunosuppressive cytokine, interleukin-4, prevents complement-dependent cytotoxicity in cancer cells, which consequently accelerates the malignant transformation of IPMN dysplasia [61,62].