Alpha-fetoprotein in ontogenesis and its association with malignant tumors.

The major steps in development of ontogenesis and the role of alpha fetoprotein (AFP) synthesis are outlined. AFP is defined and its physiocochemical characteristics are described including methods of detection and identification. The liver and yolk sac of fetuses are shown as the principle sites of AFP synthesis in ontogenesis, and the dynamics of AFP in ontogenesis from the early embryonic period through midpregnancy to pregnancy termination to AFP shut-down in early postnatal period are displayed. AFP synthesis during regeneration of the liver provides the model for studying the nature of AFP production. The role of AFP in hepatocellular cancer receives a great deal of attention, focusing on the site of AFP synthesis in cancer of the liver

1) Is there any external factor controlling AFP synthesis and determining its intensity? 2) Is synthesis performed only by certain cell types or is AFP production inherent in any hepatocyte? 3) Is control of AFP synthesis accomplished by regulating the intensity of the process in individual cells or by involvement of a varying number of cells? And 4) is AFP synthesis in a tumor due to maintained ability of the stem tumor cell to differentiate or is it the result of dedifferentiation of the mature hepatocyte??