Alpha fetoprotein(AFP) is a glycoprotein with a molecular weight of between 65,000 and 70,000 daltons including 4% of carbohydrate . During fetal development, AFP maintains high levels in the serum and drops to very low levels throughout the remainder of life.

AFP is elevated in the malignant diseases of hepatocellular, testicular nonseminomatous origin, and occasionally of other entodermal origin. AFP may be slightly elevated or persisted in the patients with large hepatic metastases or viral hepatitis. AFP measurement is widely accepted as tumor marker and for monitoring the therapeutic effectiveness of hepatocellular cancer and nonseminomatous testicular cancer .