Which marker is incorrectly paired with the disease it is used to monitor?

Which marker is incorrectly paired with the disease it is used to monitor?

• A. CEA/choriocarcinoma.
• B. CA125/ovarian adenocarcinoma.
• C. CA 19-9/pancreatic adenocarcinoma.
• D. CA 15-3/breast adenocarcinoma.

Answer: (A)

The key idea is that tumor markers are usually used to monitor specific cancers, reflecting activity of the tumor type. CEA is a general marker most commonly used to track colorectal cancer and some other GI cancers, and it can be elevated in various conditions, but it is not the standard marker for choriocarcinoma. Choriocarcinoma is monitored by detecting and following levels of human chorionic gonadotropin (hCG), which directly reflects trophoblastic tumor activity. The other pairings are correct: CA125 is used to monitor ovarian epithelial cancer, CA19-9 for pancreatic adenocarcinoma, and CA15-3 for breast cancer. So the mismatched pairing is CEA with choriocarcinoma.

The key idea is that tumor markers are usually used to monitor specific cancers, reflecting activity of the tumor type. CEA is a general marker most commonly used to track colorectal cancer and some other GI cancers, and it can be elevated in various conditions, but it is not the standard marker for choriocarcinoma. Choriocarcinoma is monitored by detecting and following levels of human chorionic gonadotropin (hCG), which directly reflects trophoblastic tumor activity. The other pairings are correct: CA125 is used to monitor ovarian epithelial cancer, CA19-9 for pancreatic adenocarcinoma, and CA15-3 for breast cancer. So the mismatched pairing is CEA with choriocarcinoma.