Placental ALP is used as tumor marker of
**Core Concept**
The question tests the knowledge of tumor markers and their association with specific cancers, focusing on placental alkaline phosphatase (PLAP). PLAP is an isoenzyme of alkaline phosphatase, which is typically found in the placenta but can also be expressed in certain types of tumors.
**Why the Correct Answer is Right**
PLAP is used as a tumor marker for seminoma, a type of testicular cancer, and some other germ cell tumors. Its expression in these tumors makes it a useful marker for diagnosis and monitoring. The enzyme is also found in non-seminomatous germ cell tumors and can be elevated in various other conditions, but its primary association is with seminomas.
**Why Each Wrong Option is Incorrect**
**Option A:** This option would be incorrect because while PLAP can be elevated in various conditions, the specific tumor marker association being asked is not related to this choice.
**Option B:** Similarly, this option does not correctly identify the primary tumor type associated with PLAP as a tumor marker.
**Option C:** This option is incorrect as it does not specify the correct tumor type associated with PLAP.
**Clinical Pearl / High-Yield Fact**
Remembering that PLAP is a marker for seminomas and certain other germ cell tumors is crucial. This knowledge can aid in the diagnosis and management of testicular cancers, highlighting the importance of tumor markers in oncology.
**Correct Answer:** D. Seminoma