The CEA level in a cystic fluid is higher in mucinous cysts, and in the differential diagnosis of IPMN between benign and malignant tumors, the sensitivity and specificity were reported to be 90% and 71%, respectively, when CEA >200 ng/mL was used as the cutoff and 87.5% sensitivity and 73% specificity when CA72‐4 >40 U/mL was used as the cutoff. The gene discussed is CEACAM5; the disease is pancreatic intraductal papillary-mucinous neoplasm.