SPI1 and acute myeloid leukemia: USP22 deubiquitinates H2BK120Ub to regulate the expression of inflammatory and immune responsive genes. Its KO induces cell‐intrinsic emergency haematopoiesis with increased HSC proliferation and extramedullary haematopoiesis [18]. *USP22 deubiquitinates and stabilises PU.1 and its KO facilitates transformation in Ras‐driven AML [36]. *USP22 stabilises SIRT1 in FLTD‐ITD AML cells [32].