The life span of cells is limited and dying cells are replaced with new ones, differentiated cells derived from stem . Stem cells in the adult organism can be detected markers present in both embryonic stem cells and stem cells in the tissues. Examples of the protein markers are : Oct3 / 4 , CXCR4 , Nanos , CD133 , CD34 . Common features of stem cells include: 1) the ability for self-renewal ( division created after the new stem cells ), 2 ) the ability to differentiate into specialized cells of tissues and organs, 3 ) resistance to stress and radiation toxicity .