KLRK1 and tonsil cancer: Patients with low expression of KLRK1 or high expression of ULBP2/3 had worse prognosis than those with low expression of ULBP2/3 (P < .01, Fig. 11A, C, and D), whereas the expression level of ULBP1 had no significant effect on the prognosis of tonsil cancer (P = .770, Fig. 11B).