PRF1 and sarcoma: NKG2D-mediated immunoediting was also reported in MCA-sarcoma models from mice lacking perforin (Prf1−/−) and in B cell tumors from NKG2D-deficient mice (Klrk1−/−) (Guerra et al., 2008; Iguchi-Manaka et al., 2008; Takeda et al., 2005).