AFP (alpha-fetoprotein) is elevated in which two malignancies where it is used as a tumor marker, and what is its molecular weight?

• A Cholangiocarcinoma and seminoma; ~70 kDa
• B Hepatocellular carcinoma and pancreatic carcinoma; ~19 kDa
• C Hepatocellular carcinoma (HCC) and non-seminomatous germ cell tumors (NSGCT); ~70 kDa ✓
• D Cholangiocarcinoma and yolk sac tumor; ~140 kDa

Explanation

AFP (~70 kDa glycoprotein) is physiologically produced by fetal liver, yolk sac, and GI tract; normal adult levels are <10 ng/mL. Pathologically elevated AFP is characteristic of hepatocellular carcinoma (>400 ng/mL is highly specific) and non-seminomatous germ cell tumors (NSGCT) — specifically yolk sac tumor (endodermal sinus tumor). Pure seminomas do not produce AFP (AFP elevation in a presumed seminoma suggests non-seminomatous elements). AFP is also elevated in benign conditions: cirrhosis, viral hepatitis, and importantly in physiological fetal life and neural tube defects (elevated in maternal serum).

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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