Tumor markers are proteins that are abnormally increased in blood or urine or in secretions, which can be clarified by laboratory tests. After the occurrence of malignant tumor, this protein will increase significantly, and its increase can indicate the occurrence of malignant tumor. The tumor markers of ovarian cancer are mainly divided into CA125, CA199, AFP and HE4. The tumor marker CA125 will be significantly increased in ovarian plasmacytoma cystic carcinoma, often >600 U/L; CA199 is often significantly increased in ovarian mucinous cystic carcinoma, >600 U/L; both CA199 and AFP may be increased in malignant ovarian teratoma. There are also some special cases with specific tumor markers that may manifest themselves. But let’s summarize, the most core, most useful and widest range of ovarian cancer tumor markers are CA125 and CA199.