Low-dose Radiation Improves Tumor Immune Microenvironment, Enhancing the Effects of Anti-CTLA-4 Therapy.

Background: Radiotherapy destroys tumor cells primarily through direct DNA damage by high-energy particles or indirect DNA damage by free radicals. High-dose radiotherapy (HDR) destroys tumor cells while also damaging normal cells and may potentially cause immunosuppression. The effect of low-dose radiotherapy (LDR) on the tumor microenvironment (TME) may differ from those of HDR.