Physical mechanisms of the activation of oncogenes through carcinogens.

In the last years about twenty human oncogenes have been discovered. It is shown that their main activation mechanisms: through non Watson-Crick-type point mutation, through activation by LTR binding to the end of an oncogene and through transposition of an oncogene to another chromosome need an external agent. The principal mechanisms of short- and long-range effects of chemical carcinogens are reviewed. A possible very effective mechanism for long-range effects of chemical carcinogenesis through generation of conformational solitons in DNA are discussed in detail.