Alpha-fetoprotein (AFP) - new aspects of a well-known marker in perinatology.

Alpha-fetoprotein (AFP) is a serum protein, which is characteristic of the fetal development period and a well-known oncological marker. The predominance of AFP among serum proteins is common in fetal life, whereas after birthing its functions are gradually taken over by albumins. An understanding of the mechanism of AFP transfer between fetus and mother has led to the development of screening tests for identifying neural tube defects and Down's syndrome. Currently, the knowledge on patophysiology and the possible importance of AFP in perinatology and fetal medicine extends far beyond those 2 disease states. Throughout the 50 years of research on AFP, there has been dynamic progress of diagnostic techniques, from the qualitative ones that are used solely for scientific studies to the widely used radioimmunoassays and immunoenzymatic assays (enzyme-linked immunosorbent assay, chemiluminescence immunoassay, time-resolved fluorescence immunoassay). Some genetic mutations cause complete inhibition of AFP production by the fetus. This affects the results of screening tests during pregnancy, and also leads to constantly high levels of AFP in adults, which are not linked to oncogenesis.