A new era of functional experimentation in human hematopoiesis and leukemia research.

Functional experimentation has laid the foundation for our understanding of hematopoietic and leukemic stem cells. Yet, most recently, a flurry of descriptive studies of primary human cells, fueled by rapid technological advances in sequencing technologies, have emerged. These increasing opportunities to describe at great detail have taken precedence over rigorously interrogating functional mediators of biology, particularly in primary human cells. Here, we argue that an improved toolset of gene editing and stem cell biology technologies will allow the field to expand beyond extensive descriptive studies to more functional studies.