The data showed a decreased number of CD56dim NK cells in the peripheral blood of SS patients, impaired expression of NK-activating receptors, such as NKG2D and NKG2C, and expansion of “memory” CD57+NKG2C+ NK cells, together with increased sMICA/MICB, which acts as tumor escape mechanism. Here, KLRK1 is linked to synovial sarcoma.