TPO and acute myeloid leukemia: A strong positive correlation between the thrombopoietin (TPO) level and c-MPL expression is found in the bone marrow mononuclear cells of relapsed AML patients. A high level of TPO/c-MPL signalling may protect MSCs from daunorubicin chemotherapy in AML. The effects of inhibition of the TPO/c-MPL pathway on enhancing the chemotherapy sensitivity of AML cells and on their downstream effector molecules that direct the interactions between patient-derived blasts and leukaemia-repopulating cells need to be further studied.