This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
CA-125 is a marker antigen for the screening of the following malignancy: 
Select and explain. 
A. Prostate cancer, B. Breast cancer, C. Brain cancer, D. Ovarian cancer
D: Ovarian cancer
Answer: D: Ovarian cancer 
Explanation: CA125 is a glycoprotein that is not produced by normal ovarian epithelium, but may be produced by both benign and malignant ovarian tumors. Most commonly, cancer antigen 125 (CA125) level measurements and/or transvaginal sonography have been used for screening of ovarian tumors in suspected individuals. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 35. Epithelial Ovarian Cancer. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.