Alpha-fetoprotein, also known as AFP, is a relatively commonly used tumor marker, which is an indicator formed mainly from fetal hepatocytes and yolk sac, and may be more closely related to primary liver cancer. Clinically, if this indicator is greater than 400μg/L for one month or greater than 200μg/L for two months, and combined with imaging examination, occupying lesions on the liver are found, a clinical diagnosis of primary liver cancer can be made. Of course this index, if mildly elevated, does not diagnose liver cancer. Other tumors or benign lesions may cause mild elevation of alpha fetoprotein. In addition to primary liver cancer, alpha fetoprotein may also be elevated in patients with hepatitis and other reproductive tumors, such as testicular cancer, ovarian tumors, and malignant teratoma.