CXCR2 and chronic myelogenous leukemia, BCR-ABL1 positive: MSCs also play a role in maintaining CML stem cells in the BMM and TKI resistance through the upregulation of promyelocytic leukemia (PML), a tumor suppressor protein, and the cell quiescence regulator, to repair double-strand DNA breaks in MSCs that are used to upregulate inflammatory cytokines such as IL-6, IL-8 (CXCR2L) and CXCL1/CXCR2 as well as activation of various signaling pathways [83].