Major relevant tumors: one of the best tumor markers for gastric cancer. Other related tumors: It also has different detection rates for other gastrointestinal cancers, breast cancer, lung cancer, ovarian cancer, etc. Other influencing factors: benign diseases have less effect on CA72.4. CA72.4 is one of the best tumor markers for the diagnosis of gastric cancer, with high specificity and sensitivity up to 28-80%, if combined with CA19-9 and CEA, it can monitor more than 70% of gastric cancers. CA72.4 levels can rapidly decrease to normal after surgery. In 70% of recurrent cases, CA72.4 concentrations are first elevated. The main advantage of CA72.4 over other markers is its extremely high specificity for the differential diagnosis of benign lesions, with a detection rate of only 0.7% in a large number of patients with benign gastric disease. CA72.4 also has varying degrees of detectability for other gastrointestinal cancers, breast cancer, lung cancer, and ovarian cancer.CA72.4 in combination with CA125 has a specificity of 100% as a marker for the diagnosis of primary and recurrent ovarian tumors.