Alterations of the expression of relevant activating receptors such as the natural cytotoxicity receptors (NCRs: NKp30, NKp44, and NKp46) have been observed in blood from acute myeloid leukemia (AML) patients [18]; in addition, recent studies in breast [19], lung [20,21], colorectal cancer (CRC) [22,23], renal cell carcinoma [24], and gastrointestinal stromal tumors [25] have shown that intratumor NK cells display phenotypic and/or functional alterations compared with peripheral NK cells. Here, NCR2 is linked to acute myeloid leukemia.