Transit Amplifying Cells

Every multicellular organism begins its existence as small groups of stem cells, which can be defined as cells that are able to replicate themselves many times without errors. Tissues also contain transit amplifying cells, which arise from stem cells in a tissue, yet only divide a finite number of times before they become differentiated.

Transit amplifying cells (TACs) are specialized and characteristically can divide if they are present during organismal development, yet typically their division capacity in adult tissues is only triggered during injury conditions in order to replace damaged tissues. Transit amplifying cells have received many designations in the literature, including progenitor cells, precursor cells, lineage stem cells, and tissue-determined stem cells.