Furthermore, it is also possible that iron overload in MDS BM due to the ineffective erythropoiesis and frequent blood transfusions [57], induces HO-1 expression, resulting in increased HO-1 expressing macrophage differentiation, which in turn suppresses erythropoiesis (as these macrophages infiltrate the BM and physically interrupt erythropoiesis) and thus causes more cytopenia. Here, HMOX1 is linked to myelodysplastic syndrome.