We investigated toxicities of high-dose thoracic radiation in wild-type (WT), Dr5–/–, or Trail–/– C57BL/6 mice to test outcomes predicted in Figure 1A. We hypothesized that Dr5–/– mice would have severe radiation-induced pneumonitis and would not be rescued by either TRAIL or TIC10/ONC201 (40). This evidence concerns the gene TNFSF10 and pneumonitis.