[Relevance of apoptosis for carcinogenesis]

Apoptosis is a type of active, genetically programmed cell death. It occurs under specific conditions and is characterized by it's morphology. It is controlled by genes, hormones and other factors regulating the growth of organs and cells in the organism. In the liver and some other epithelial tissues transforming growth factor beta 1 and related peptides seem to be involved in the homeostasis of cell multiplication and cell death. In the course of carcinogenesis, initiated, preneoplastic and neoplastic cells and cell foci in the liver show enhanced DNA synthesis and also enhanced apoptosis. Tumor promoters inhibit apoptosis and increase cell replication and can thereby shift the balance between birth and death of cells accelerating tumor development. Fasting can have the opposite effect.