Autocrine Secretion and Carcinogenesis

Continuous secretion of a variety of growth factors, hormones and other regulatory elements is a common characteristic of tumor cells. The inappropriate control of the expression of some tissue-specific proteins and the ectopic synthesis of biologically active molecules such as various autocrine mitogenes, transforming growth factors, and differentiation-inhibiting or differentiation-inducing factors, result from a pleiotropic effect of oncogene activities in malignant cells that derepress and/or keep active a number of genes, which are normally silent in differentiated cells (1). Available literature on growth factors and hormones secreted by both normal and malignant cells is so vast that inevitably a reduced number of contributions will be referenced in this short overview.