SMAD2 and myelodysplastic syndrome: It has been reported that TGF‐β inhibits erythropoiesis by blocking proliferation and accelerating differentiation of erythroid progenitors in vitro.[48] In addition, overactivation of TGF‐β/Smad2 signaling has been observed in bone marrow precursors of patients with myelodysplastic syndrome (MDS),[37] which is characterized by ineffective erythropoiesis.