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Alpha-Fetoprotein: Tumor Marker in Testicular Cancer

Alpha-fetoprotein (AFP) is a glycoprotein (molecular weight 69.000 Dalton, 4% carbohydrates) with great similarity to albumin. It is produced in the embryonic liver, intestine and yolk sac. AFP is not produced after birth. In healthy adults, alpha-fetoprotein is detected only in low concentrations.

Standard Value of Alpha-Fetoprotein

< 15 ng/ml or < 10 IU/ml (1 IU = 1.2 ng).

Laboratory Test Method

ELISA.

Indications

Diagnosis and follow-up in germ cell tumors and hepatocellular carcinoma.

Differential Diagnosis of Increased Alpha-Fetoprotein

• Germ cell tumors: testicular cancer (nonseminoma), tumors of the ovary, extragonadal germ cell tumors. Mature teratomas, pure seminomas or pure choriocarcinomas do not produce AFP.
• Hepatocellular carcinoma
• Transient and mild increase of AFP in benign liver diseases
• Pregnancy

Kinetics of AFP after Treatment of Testicular Cancer

After a complete tumor resection, postoperative concentration decline to the normal range with a half-live of five days. An incomplete or slow decrease after radical orchiectomy is suspicious for metastasis of germ cell tumor. A rebound of AFP after normalization is a sign of tumor recurrence or metastasis. A rising AFP level is incompatible with healing of testicular cancer and can indicate tumor progression weeks or months before radiological diagnosis.

References

  Deutsche Version: Alpha-Fetoprotein