ULBP1 and acute myeloid leukemia: Immune evasion in NPM1-mutated AML is also contributed by VISTA (V-domain Ig suppressor of T-cell activation) and ULBP1 (NKG2 ligand) immunoregulatory circuitries that are both significantly upregulated in NPM1-mutated AML patients [126] (Fig. 4).