Which tumor marker is commonly associated with prostate and testicular cancer?

Prostate-Specific Antigen (PSA) is a protein produced by both normal and malignant cells of the prostate gland. It is primarily used as a tumor marker to screen for and monitor prostate cancer, making its association with prostate cancer particularly significant. Elevated levels of PSA in the blood can indicate the presence of prostate cancer, benign prostatic hyperplasia, or prostatitis. While PSA is primarily known for its role in prostate cancer, it is also relevant in the context of certain testicular cancers, particularly non-seminomatous germ cell tumors, where it may be elevated.

In contrast, CA-125 is predominantly associated with ovarian cancer, LDH is a marker that can indicate a number of conditions, including certain lymphomas and testicular cancers but is not specific to prostate cancer. B2-Microglobulin is involved in multiple myeloma and lymphomas and is not typically linked to either prostate or testicular cancer. Thus, PSA stands out as the key tumor marker associated with both prostate and testicular cancers, confirming its relevance in the context of this question.