Human epididymal protein 4 (HE4) is a tumor cell surface antigen in female ovarian cancer. Especially for patients with benign ovarian cancer, HE4 is currently the most sensitive tumor marker for ovarian cancer diagnosis. Human epididymal protein 4 (HE4) is a tumor cell surface antigen in female ovarian cancer. Although cancer antigen 125 (CA125) is widely used in clinical diagnosis of ovarian cancer detection, studies have shown that HE4 has advantages over CA125 in early diagnosis of ovarian cancer, especially for patients with benign ovarian cancer. HE4 is currently the most sensitive tumor marker for ovarian cancer diagnosis.