CCL21 and chronic myelogenous leukemia, BCR-ABL1 positive: On the contrary, Kubo et al. observed that BCR-ABL cooperated with signal transducing adaptor protein (STAP)-2 to induce the expression of CCR7 and CXCR4 and the production of the ligands for CCR7, CCL19, and CCL21, in a murine hematopoietic BaF/3 cell [100], raising the possibility of the contribution of the CCR7 axis to CML cell proliferation.