CTLA4 and neoplasm: Given that the activation of CTLA−4 signaling and expansion of regulatory T-cells was observed in the DVL3 tumors following RT and αCD40mAb combination therapy we therefore hypothesized that the addition αCTLA−4mAb would abrogate the immunosuppressive CTLA−4 signaling and result in enhanced tumor control (treatment schema shown in Figure 6a).