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
Bilateral ovarian masses are identified on pelvic examination of a 40 year old woman. Ultrasound examination reveals multiloculated cystic masses involving both ovaries. The patient is treated with total abdominal hysterectomy with removal of both adnexa. Pathologic examination demonstrates papillary carcinoma producing serous fluid. Which of the following tumor markers would be most useful in monitoring for recurrence? 
Select and explain. 
A. Alpha-fetoprotein, B. Bombesin, C. CA-125, D. PSA
C: CA-125
Answer: C: CA-125 
Explanation: The tumors are serous papillary cystadenocarcinomas of the ovaries. These tumors express CA-125 and are apparently derived from the surface epithelium of the ovaries. Alpha-fetoprotein is not produced by this type of ovarian tumor, but can be produced by testicular tumors, and less commonly, by ovarian tumors with a yolk sac tumor component. Bombesin is a marker for neuroblastoma, small cell carcinoma, gastric carcinoma, and pancreatic carcinoma. PSA is a marker for prostatic carcinoma. 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.