FETOPROTEIN, ALPHA-

A plasma protein, alpha-fetoprotein (AFP) is normally produced by the fetus. The level of AFP in the blood serum of pregnant women provides a screening test for open neural tube defects (anencephaly and spina bifida) and for Down syndrome (and other chromosome abnormalities). The maternal serum AFP (MSAFP) tends to be high with open neural tube defects and low with Down syndrome. AFP is also paradoxically produced by liver tumors (hepatomas) and germ cell tumors (teratocarcinoma and embryonal cell carcinomas) and so can be used to help detect and monitor the treatment of these tumors.