Growth factors and oncogenes.

The regulation of the production of normal cells of the skin, blood and intestine has attracted considerable interest since the very earliest days of tissue culture(1,2). The proliferation of normal cells has long been known to depend on specific proteins called growth factors. However, the experimental systems were so complex and poorly understood, that only the persistence of a few biochemists kept the rather complex field of growth factor chemistry moving forward(3). Now, after the discovery of the retroviral oncogenes(4) and their cellular equivalents, it is our knowledge of growth factors(6-12) their receptors(9) and their mode of action (11,12), which is paving the way for understanding the functional nature of the molecular lesions which give rise to cancer cells(13-16). Each cellular system has its unique features but here Tony Burgess discusses some of the similarities in the molecular regulation of proliferation and differentiation in both normal and transformed cells from several different tissues.