Turkish Journal of Hematology, cilt.25, sa.2, ss.57-59, 2008 (SCI-Expanded)
Stem cell biology and regenerative medicine is a relatively young field. However, in recent years there has been a tremendous interest in stem cells possibly due to their therapeutic potential in disease states. As a classical definition, a stem cell is an undifferentiated cell that can produce daughter cells that can either remain a stem cell in a process called self-renewal, or commit to a specific cell type via the initiation of a differentiation pathway leading to the production of mature progeny cells. Despite this acknowledged difinition, the classification of stem cells has been a perplexing notion that may often raise misconception even among stem cell biologists. Therefore, the aim of this brief review is to give a conceptual approach to classifying the stem cell, beginning from the early morula stage totipotent embryonic stem cells to the unipotent tissue-resident adult stem cells, also called tissue-specific stem cells.