Which tumor marker is most useful for identifying early relapse in testicular cancer?

Alpha fetoprotein (AFP) is a tumor marker that is particularly useful in the context of testicular cancer, especially in identifying early relapse. In testicular cancer, especially non-seminomatous germ cell tumors, elevated levels of AFP can indicate the presence of disease or a recurrence after treatment.

AFP is produced by the fetal liver and, under normal circumstances, is present in high levels in fetal blood but decreases to very low levels after birth. In adults, elevated AFP levels can suggest several pathological conditions, including liver disease and germ cell tumors.

In the case of testicular cancer, healthcare providers monitor AFP levels post-treatment as a way to detect any resurgence of cancer early, which is crucial for timely intervention. By understanding that AFP is reliably associated with certain types of testicular tumors, clinicians can efficiently track the disease's progression or return.

The other markers listed, such as carcinoembryonic antigen (CEA), prostate-specific antigen (PSA), and CA 125 glycoprotein, are associated with different types of cancers or conditions. CEA is primarily used in colorectal cancer monitoring, PSA is specific to prostate cancer, and CA 125 is primarily involved in monitoring ovarian cancer. Hence, they are not relevant or effective