| Abstract: | Data about polypeptide growth factors in animal cells during embryogenesis and about the sensitivity of these cells to regulatory effect of the factors have been systematically reviewed. The conclusion was drawn that they play an important role in molecular mechanisms controlling cell proliferation and differentiation at the early embryonic stages. Information has also been provided about transforming growth factors and about the products of some proto-oncogenes, which are detected in the embryonic cells in amounts comparable with those in the transformed cells. However, this does not lead to malignant growth. Moreover, microenvironment of an intact embryo exerts an antitransforming influence on tumor cells. Studies of the "normalizing" effect of the embryonic cells may help in developing new methods of suppression of the malignant growth. |
