KLRC1 and neoplasm: As NKG2A inhibits NK cell activation by binding to the major histocompatibility complex (MHC) class I 12, the decreased expression of NKG2A on NK cells suggested that NK cells in tumor of HSCT recipients (HSCT tumor) had a lower threshold for activation than cells in tumor of no‐treatment mice (non‐HSCT tumor) did, and led to an effective antitumor immunity in MHC class I+ tumors such as CT26.