Dr. Chan's research focuses on the biology of aging in stem cells and stem cell niches. Niches are the highly specialized but poorly understood microenvironments that regulate stem cell activity. Using a reductionist approach, Dr. Chan has pioneered techniques to identify and isolate stem/progenitor cells of individual tissue types, including bone, cartilage, and blood vessels. These basic components can also be combined together to reconstitute a functional bone marrow niche that can support hematopoietic stem cells (HSCs). Dr. Chan's group recently identified a mouse skeletal stem cell (mSSC) that has the ability to make bone, cartilage, and HSC niches, in vitro and in vivo, and they are also close to reporting on the isolation of the human skeletal stem cell (hSSC).