CA199 is an antigen of tumor marker. CA199 is medically known as the antigen of tumor marker, which is generally found between the epithelial cells of the human body. CA199 (antigen of tumor marker) is a kind of examination that can be used as one of the evaluation criteria for the treatment effect of tumor patients. CA199 (tumor marker antigen) check out of the simple CA199 mildly elevated patients do not have to worry too much, because this situation also occurs in the normal population, the existence of benign diseases patients will also appear in this mildly elevated phenomenon. If the CA199 (tumor marker antigen) test reveals persistent or multiple increases in CA199 (tumor marker antigen), it is necessary to consider that it is related to gastrointestinal and pancreatic malignant tumors. It is recommended that people go to the hospital for regular checkups to avoid discomfort.