Enigmatic niche brings challenge for HSC expansion

The bone marrow niche keeps puzzling scientists in cancer and regenerative medicine. What elements constitute the niche and how it affects neighbor cells in different disease contexts remain to be a matter of debate and extensive investigation. The translational use of hematopoietic stem cells (HSCs) in transplantation biology poses a challenge, given the propensity of these cells to remain quiescent. Although the niche is a good candidate to exploit for reprogramming HSCs and controlling their expansion, new studies have added to its complexity. In 'Bench to Bedside', Paul S. Frenette and Yuya Kunisaki examine these studies to discuss how new players and their signals are involved in HSC maintenance and what the implications are for the development of HSC-based therapies. Among the alterations occurring in leukemias, metabolic events seem to foster cancer progression but may also be involved in cancer predisposition. Rushdia Z. Yusuf, Ying-Hua Wang and David T. Scadden peruse recent clinical and experimental studies that look at myelodysplastic syndromes and secondary leukemias and argue how metabolic changes in these cancers may not only be cell autonomous but also can emanate from the bone marrow stroma. Targeting this niche may open new avenues to reduce the risk for secondary leukemias in cancer survivors.