Journal ArticleTo the Editor: The presence of amplified growth factor systems in many tumor models, including malignant gliomas, raises the question of how such external signals are transduced into a transformed phenotype (increased proliferation, invasion, lack of contact inhibition, angiogenic capacity, etc.). In this regard, intracellular signal transduction systems a re likely to play a key role. Such amplified external signals, by way of transduction systems, may alter genomic expression to effect a change of the expression of structural or regulatory genes to produce the malignant phenotype. Furthermore, the complexity and multiplicity of the growth factor systems place therapeutic impetus upon determining events that follow growth factor/receptor binding. Determination of postbinding events may reveal common intracellular transduction mechanisms activated by these different signals
