The clinical significance of Carbohydrate antigen 199 (CAl9-9) Carbohydrate antigen 199 (CAl9-9) is an oligosaccharide tumor-associated antigen (reference value <37ng/m1) that is a sensitive marker for pancreatic cancer. Clinical significance: 1) It is a sensitive marker of pancreatic cancer, especially elevated in patients with advanced pancreatic cancer, and is an important adjuvant diagnostic indicator. 2) It is also significantly elevated in biliary, rectal, colon and gastric cancers. 3) It can also be elevated in ovarian cancer, lymphoma, lung cancer and breast cancer. 4) It is elevated in acute and chronic pancreatitis, cholecystitis, cholelithiasis, liver cirrhosis, renal insufficiency, diabetes and other benign diseases, but At this time, the increase in CA-199 is often low or transient. 5), for efficacy observation and prognosis judgment and monitoring for recurrence. The survival of those whose CA-199 decreased to normal after surgery is longer than that of those whose CA-199 did not decrease to normal. The combination of CA-199 with AFP and CEA is more effective for the diagnosis of gastrointestinal tumors and the determination of recurrence. (From Prof. Jianshu Chang's personal website, to share knowledge with you) Yue-Rong Li, Department of Infectious Diseases, Zhangqiu People's Hospital