Stem cells are different from the other kinds of cells found in the body. They have three general properties:

~they are capable of replicating themselves many times
~they do not have any tissue-specific structures that allow them to perform specialized functions, but
~they can give rise to specialized cell types

An adult stem cell is thought to be an undifferentiated cell. Its primary role in a living organism is to maintain and repair the tissue in which it is found. In some studies, scientists have found that adult cells are present in more tissues than once thought possible. If the differentiation of adult stem cells can be controlled in the laboratory, researchers believe that these cells may become the basis of transplantation-based therapies in the future.