Which one of the following is not used as a tumor marker in testicular tumors?
**Core Concept**
Testicular tumors are a type of germ cell tumor that require accurate diagnosis and monitoring for optimal treatment. Tumor markers are substances produced by the tumor cells that can be detected in the blood and are used to monitor the response to treatment and detect recurrence.
**Why the Correct Answer is Right**
The correct answer is **human chorionic gonadotropin (hCG)** is not a tumor marker for seminomas, which are a type of non-germ cell tumor. However, hCG is a tumor marker for choriocarcinoma, a type of non-seminomatous germ cell tumor. In contrast, alpha-fetoprotein (AFP) and lactate dehydrogenase (LDH) are tumor markers for non-seminomatous germ cell tumors, including seminomas and non-seminomatous germ cell tumors.
**Why Each Wrong Option is Incorrect**
* **Option A:** Alpha-fetoprotein (AFP) is used as a tumor marker for non-seminomatous germ cell tumors, including seminomas and non-seminomatous germ cell tumors.
* **Option B:** Lactate dehydrogenase (LDH) is used as a tumor marker for non-seminomatous germ cell tumors, including seminomas and non-seminomatous germ cell tumors.
* **Option C:** Human chorionic gonadotropin (hCG) is used as a tumor marker for choriocarcinoma, a type of non-seminomatous germ cell tumor.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the combination of tumor markers can provide valuable information for the diagnosis and monitoring of testicular tumors. For example, an elevated AFP level with a normal hCG level may suggest the presence of a non-seminomatous germ cell tumor.
**Correct Answer: C. hCG**