Despite shared AKT and ERK signaling in FLT3 and CXCR4 downstream pathways, BM stroma-mediated resistance to quizartinib in FLT3-ITD-AML was mediated through persistent activation of ERK, not AKT, consistent with a previous report under different co-culture conditions [21]. Here, CXCR4 is linked to acute myeloid leukemia.