CA199 as high as 2000 can be the result of benign diseases such as uterine fibroids, fatty liver, cholestasis, etc., or malignant diseases such as pancreatic cancer and colorectal cancer. CA199 is a mucin antigen that can be found in the epithelial tissues of the gastrointestinal and pancreatic glands of the human fetus. Adult tissues such as the liver, lungs, and pancreas may also contain low levels of this mucin. Its measurement is primarily useful in the identification and pathologic detection of pancreatic cancer. However, the specificity of CA199 is low, and many diseases can show an increase in CA199, even a severe increase. For example, certain benign gynecological diseases, such as uterine fibroids, ovarian cysts, teratomas, adenomyosis and so on. Gallbladder diseases, such as cholecystitis, cholestasis, gallstones, and even some pneumonias and diabetes can show a rise in CA199. Of course there are some malignant diseases, such as pancreatic cancer, colon cancer, rectal cancer and other malignant tumors can also appear CA199 rise. Therefore, when CA199 rises, it is necessary to combine with other tests and clinical symptoms to make a comprehensive judgment, and not to jump to conclusions too early.