[The oncogene concept: molecular biological methods and parameters for characterizing gastrointestinal tumors]

Hitherto, research on diagnosis and therapy of cancer has been mainly of empirical nature. Besides some promising results in both fields of cancer research using traditional techniques, cell biological approaches offer a better understanding of the regulation of growth and differentiation. Immunological and, particularly, molecular biological methods contribute to this optimism. However, the use of new methods does not necessarily mean that correlation studies elucidate causal relations. Besides methodological explanations this article reviews general aspects of protooncogenes, their activation and the impact of growth factors and receptors in the multistep process of malignant development. The second part focuses on clinical applications of molecular and cellular biological analyses of gastrointestinal tumors.