Postradiation DNA polymorphism.

The presence of DNA molecules with tumor-specific genetic alterations has been demonstrated in the plasma of cancer patients. Such plasma DNA fragments may be immunogenic and provide immunologic support to the malignant cells. Further, the tumor-specific plasma DNA may participate in the adaptive processes of the tumor cells in the cancer host. The mechanisms of the latter are unclear. However, from the standpoint of the resistance problem, understanding of DNA transformation after exposure of extreme factors is of great interest.