Alpha-fetoprotein

Definition

• A glycoprotein normally produced by the fetal liver, yolk sac, and GI tract.
• Serum levels are high in fetuses, but fall to very low levels after birth.
• In adults, elevated AFP is considered abnormal and often suggests malignancy or liver disease.

Oncology Relevance

• Tumor Marker:
  • Hepatocellular carcinoma (HCC) → elevated AFP is a key diagnostic and monitoring marker.
  • Germ cell tumors (especially non-seminomatous testicular cancers like yolk sac tumors, embryonal carcinoma, mixed germ cell tumors).
• Monitoring:
  • Used to assess treatment response and recurrence in HCC and germ cell tumors.
  • Trend over time is more meaningful than a single value.

Non-Oncologic Elevations

• Chronic liver disease (cirrhosis, chronic hepatitis B/C).
• Pregnancy (maternal serum AFP used in screening for neural tube defects and Down syndrome).

Pharmacist Considerations

• In HCC: AFP is often combined with imaging (ultrasound, CT, MRI) for diagnosis and surveillance.
• In germ cell tumors: Always interpret AFP with β-hCG and LDH as part of tumor marker panels.
• Therapy monitoring: Falling AFP = good treatment response; rising AFP = progression/relapse.
• Limitations: Not all HCC patients have elevated AFP; normal AFP does not rule out disease.

Summary:

AFP = Alpha-fetoprotein, a tumor marker for HCC and non-seminomatous germ cell tumors, also elevated in chronic liver disease and pregnancy. It is mainly used for diagnosis, prognosis, and monitoring treatment response.