DPP4 and chronic myelogenous leukemia, BCR-ABL1 positive: CD26 (dipeptidyl peptidase-4 (DPP4)) is involved in releasing CML LSCs into the bloodstream from the BM through cleaving stromal-derived factor (SDF-1: CXCL12)-CXCR4 (CD184) axis, which can lead to the disruption of interactions within the stem cell niche and spread of the disease regardless of specific niche regulations.