[Changes in copy number and deletion development of mitochondrial DNA in blood cells from breast cancer patients during radiochemotherapy].

Changes in mitochondrial DNA (mtDNA) copy number were compared versus the nuclear beta-globulin gene (internal standard), as well as occurrence of large mtDNA deletions in peripheral blood samples from 21 breast cancer patients following chemoradiotherapy. The study used polymerase chain reaction. Distinct variations were identified both in mtDNA copy number versus nuclear DNA and large mtDNA deletions occurrence in blood cells in response to genotoxic influence of chemoradiotherapy. Some mtDNA copies in breast cancer patients blood cells revealed large deletions whose frequency increased after chemoradiotherapy. Mitochondrial DNA lesions would induce synthesis of mtDNA copies in the course of chemoradiotherapy, which pointed to a compensatory reaction in peripheral blood cells as a consequence of a disturbed energy biogenesis.