[Transforming growth factor beta. A potent multifunctional growth factor for normal and malignant cells].

The polypeptide growth factor transforming growth factor-beta (TGF-beta) is a multifunctional regulator of basic cellular functions: proliferation, differentiation, cell adhesion and interactions with the extracellular matrix. TGF-beta is part of a regulatory network of which our knowledge is still incomplete, together with other substances such as steroid hormones, oncogene products and integrins. Five isoforms for TGF-beta and five different TGF-beta receptors have been described. TGF-beta exhibits an antiproliferative effect in vitro and in vivo on many cells of epthelial, myeloid, lymphoid and mesenchymal origin together with a growth-stimulating effect on various cells like endothelial cells and epidermal keratinocytes. Production of TGF-beta and receptors for TGF-beta has been found in many cell types, both normal and malignant. Nevertheless the amount of in vivo data is too limited to identify possibilities for therapeutic intervention in the physiological and patophysiological functions of TGF-beta.