Researchers developed a new cell culture system for expanding human hematopoietic stem cells (HSCs) in the laboratory. The new system's culture medium is free of cytokines and albumin, once believed to be essential components for HSC growth. Using various molecular techniques, the team identified several chemicals that could activate necessary signaling pathways, stimulate cell proliferation, and support long-term HSC expansion. This work may help advance various HSC-related therapeutics in clinical development.