HE-4 (Human Epididymis Protein 4) is a biomarker used in assessing ovarian cancer risk. When combined with the ROMA (Risk of Ovarian Malignancy Algorithm) index, it aids in distinguishing between malignant and benign ovarian tumors. The ROMA index uses HE-4 levels along with CA-125 to provide a risk assessment for women with pelvic masses, helping guide clinical decision-making for further diagnostic or treatment interventions.