Therapeutic interventions on human xenografts promote systemic dissemination of oncogenes

We generated xenografts of human cancer cells in mice, and using immuno-FISH analysis detected multiple co-localizing signals of human DNA and eight human oncoproteins in brain cells. Signals increased dramatically five days after treatment with chemotherapy, localized radiotherapy or surgery, which could be minimized by concurrent treatment with cell-free chromatin deactivating agents. These results suggest that therapeutic interventions may potentially encourage metastatic spread which is preventable by deactivating cell-free chromatin.