AbstractThe transforming growth factors beta are a family of peptides which are involved in the regulation of cell growth and differentiation. It has been suggested that the loss of sensitivity to growth inhibition by endogenous TGF‐β may contribute to the process of carcinogenesis in epithelial systems. However, many breast cancer cells remain sensitive to the growth inhibitory effects of these peptides, suggesting that the local induction of TGF‐β could provide a pharmacological approach to chemoprevention. Triphenylethylene anti‐oestrogens, synthetic progestins and retinoids all offer potential as chemopreventative agents. A common feature of their mechanism of action is the ability to locally increase the production of the transforming growth facto