AFP is normally produced by the yolk sac and the liver during fetal development.2 AFP is the most prevalent protein found in the blood of the human fetus and is believed to play a role similar to serum albumin, which is to transport protein of hormones and micronutrients. Normally, AFP decreases steadily during the first year or life. During pregnancy, AFP levels will rise in the blood, urine, and amniotic fluid of mothers in response to fetal development. Very high levels of AFP during pregnancy are associated with fetal malformations.2
As a tumor marker, AFP analysis is used in the post-treatment phase of previously diagnosed cancers, as well as in early surveillance of cancer survivors, where the rate of decrease of AFP has diagnostic and prognostic value. Malignant conditions associated with elevated levels of AFP in the blood include:
- Hepatocellular carcinoma (a liver biopsy of a hepatocelluar carcinoma is shown in the image)
- Germ cell and yolk sac tumors
- Metastatic carcinomas of the liver