APOE and acute myeloid leukemia: Our previous studies have shown that LILRB4 is specifically expressed on monocytic AML cells and bind to apolipoprotein E (APOE) and to recruit SHP-2 to its intracellular ITIMs, then followed by the activation of the downstream NF-kB signaling pathway to promote leukemia cell infiltration and T-cell inhibition [20].