Hematopoietic stem and progenitor cells (HSPCs) possess the ability to regenerate and differentiate into many different kinds of cells. HSPCs are found in high quantities in the bone marrow, but the process of extracting the cells can be difficult and painful.  Extramedullary tissue, tissue found outside of bone marrow, has been recently identified as another source of HSPCs, and scientists from South Korea have identified fat (adipose) tissue as a new and promising source, providing a sufficient quantity of cells to be used for research and therapeutic purposes. Gou Young Koh, from the Korea Advanced Institute of Science and Technology (Daejeon, South Korea), and colleagues have determined that the stromal vascular fraction (SVF) of adipose tissue, which consists of undefined stem cells, contains functional HSPCs capable of generating hematopoietic (blood-forming) cells. Specifically, the team found that the SVF cells differentiated into a variety of hematopoietic cells when tracked for at least 16 weeks post-transplantation. The team writes that: “. Our results provide compelling evidence that adipose tissue is a novel extramedullary tissue possessing phenotypic and functional [hematopoietic stem and progenitor cells].”