Concomitant synthesis of growth factors and their receptors--an aspect of malignant transformation.

Sporn and Todaro [1] have suggested that malignant transformation may involve autocrine stimulation by transforming growth factors. In an extension of this hypothesis it is proposed that the malignant phenotype may be characterized by the simultaneous expression of a growth factor and its appropriate receptor, either one of which, but not both can be expressed by normal cells.