Alpha-fetoprotein (AFP) is elevated in hepatocellular carcinoma. Which other tumour typically produces very high AFP levels, and what is the biochemical basis for AFP production?
- A Colon carcinoma; AFP is upregulated by Wnt/beta-catenin signaling in epithelial tumours
- B Prostate carcinoma; AFP is a PSA isoform produced by dedifferentiated prostate epithelium
- C Non-seminomatous germ cell tumours (yolk sac tumours); AFP is normally produced by yolk sac and fetal liver and is re-expressed in tumours with yolk sac differentiation ✓
- D Pancreatic carcinoma; AFP is produced as a result of CEA cross-reactivity in assay systems
Correct answer: C. Non-seminomatous germ cell tumours (yolk sac tumours); AFP is normally produced by yolk sac and fetal liver and is re-expressed in tumours with yolk sac differentiation
Explanation
AFP is normally produced by the yolk sac, fetal liver, and fetal GI tract during development. Non-seminomatous germ cell tumors with yolk sac differentiation (yolk sac tumors/endodermal sinus tumors) re-express AFP because they recapitulate yolk sac differentiation. Very high AFP (>1000 ng/mL) is characteristic. AFP is not related to PSA (a kallikrein protease) or CEA (a cell adhesion glycoprotein). AFP monitoring is essential for HCC and testicular NSGCT management.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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