Presence of tumor cells in the bone marrow microenvironment can block macrophage activation and inhibit the ability of macrophages to engulf tumor cells. However, treatment with chemotherapy (CTX) can induce changes that activate the macrophages and promote phagocytosis.Reprinted from Cell, Vol. 156, Pallasch CP, et al, Sensitizing protective tumor microenvironments to antibody-mediated therapy, Page 590-602, Copyright 2014, with permission from Elsevier.