TP53 and sarcoma: Our genetic experiments demonstrated that loss of Atrx increased radiosensitivity in 4 model systems: sarcoma cells in vitro, sarcoma cells transplanted into immunodeficient mice in vivo, primary KrasG12D; Trp53–/– sarcomas in P7 KP mice, and primary Trp53–/– + MCA sarcomas in P7 P mice.