NGFR and acute myeloid leukemia: Another study showed that BM biopsies of AML patients present a significant increase of CD271+ MSCs, which in turn enhance the production of reticular fibers,23 commonly associated with therapy failure and decreased overall survival.24 Several studies reported an increased number of vessels and other vascular abnormalities in AML patient-derived BM biopsies, raising the interest in antiangiogenic therapies also in AML.25 However, whether increased angiogenesis constitutes a prognostic factor for AML treatment response remains unclear.