Alpha-Fetoprotein: Tumor Marker in Testicular Cancer
Function of Alpha-Fetoprotein
Alpha-fetroprotein (AFP) is a glycoprotein (molecular weight 69.000 Dalton, 4% carbohydrates) with 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.
Reference Levels of Alpha-Fetoprotein
< 15 ng/ml or < 10 IU/ml (1 IU = 1.2 ng).
Kinetics of AFP after Treatment of Testicular Cancer
Half-life of alpha-fetoprotein is 5 days. An incomplete or slow decrease after 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 inconsistent with a tumor remission. It can take weeks to months, before the clinical detection of the progression is possible.
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
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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