[Relation of the signs of malignant degeneration and tumor cell reaction to a growth-stimulating factor].

Six clones of mouse sarcoma induced by subcutaneous implantation of a plastic film were studied. They differed in the degree of production of the transforming growth factor (TGF) and in stimulation of proliferation in semi-solid medium. The degree of cancerogenicity and cloning efficiency in semi-solid medium correlated with the reactivity of cells to TGF.