ACKR3 and acute myeloid leukemia: In addition, a recent in vivo study provided further evidence indicating that CXCR7 contributes to homing of acute myeloid leukemia and normal CD34+ progenitor cells to the bone marrow and spleen of NOD/SCID mice (Melo et al., 2018); however, further mechanistic study is needed to fully understand the role of CXCR7 in HSCs.