[Mechanisms of carcinogenesis].
Aberrations in the regulation of cell divisions and in cell differentiation, mainly by alterations of DNA, e.g. by mutations of regulator genes or DNA sequences control expression of specific genes, are involved in the development of malignancies. Also recombination processes may take part. Besides alteration of cellular DNA, incorporation of viral DNA can also give rise to neoplastic cells in which the viral oncogenes correspond to certain cellular genes. But there is also evidence that malignant transformation can be caused solely on the basis of epigenetic processes, e.g. by alterations of gene expression. Most chemicals are activated by metabolizing enzymes to their ultimate forms which can react both with DNA and RNA, or with proteins. Correlations to carcinogenic activity have been proved so far to exist only after binding to DNA. The mode of metabolization, DNA-repair, and immunological processes may decisively modify the action of carcinogenic factors, with species-, individual-, organ-, and tissue-specific factors possibly being involved.
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004279:DNA, Viral / Q000235:genetics; D005809:Genes, Regulator / Q000187:drug effects; D006801:Humans; D051379:Mice; D009153:Mutagens / Q000494:pharmacology*; D009369:Neoplasms / Q000139:chemically induced* / Q000235:genetics; D009857:Oncogenes / Q000187:drug effects; D011894:Rana pipiens; D011995:Recombination, Genetic / Q000187:drug effects
D004279:DNA, Viral; D009153:Mutagens
Mechanismen der Kanzerogenese.