Since MAIT cells exert cytotoxic activity against bacteria-infected tumor cells in a NKG2D and CD161-independent manner, but in an MR1-dependent manner [41], it has yet to be deciphered whether MAIT cells kill intact (not bacterially infected) tumor cells; should this be the case, which and how killer-cell-associated receptors engage in cytotoxic activity should be determined. Here, KLRB1 is linked to neoplasm.