The most important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely, whereas progenitor cells can divide only a limited number of times.Controversy about the exact definition remains and the concept is still evolving. Bone marrow stromal cells, basal cell of epidermis have 10% of progenitor cell, although they are often classed as stem cells due to their high plasticity and potential for unlimited capacity for self-renewal. 2  Periosteum contains progenitor cells that develop into osteoblasts and chondroblasts.