The search of the literature was performed using databases PubMed and Web of Science, using the keywords “Human Epididymis protein 4,” “HE4,” or “WFDC2 (whey-acidic-protein four-disulfide core domain protein 2)” combined with the terms “Ovarian Cancer/Cancer”, ”Blood/Serum/Urine”, “Tumor Marker”, “Diagnostic” or “Prognostic” published from a period from 2010 to 2024. The gene discussed is WFDC2; the disease is neoplasm.