For that reason, the expression of HLA-I and HLA-C, main ligands of iKIRs and aKIRs, and that of CD112/CD155 and ULBP-1/MICA/B, ligands of CD226 and NKG2D, respectively, were prospectively analyzed on B-ALL, T-ALL, and AML pediatric leukemic cells to ascertain their role in the outcome of these patients. The gene discussed is KLRK1; the disease is acute lymphoblastic leukemia.