Approaching stemness
So far, the main way in which researchers have sought to
get a handle on stemness has been to try to reduce stemcell
behavior - a phenomenon operationally defined at the
level of tissues and tissue reconstitution - to a set of
necessary and sufficient, intrinsic cell-level properties. The
two properties that are universally discussed are ‘potency’
and ‘self-renewal’. Stem cells, it is said, display traits of
potency and self-renewal that set them apart from other
cells. Understanding the molecular basis of these abilities,
it is argued, should lead directly to a molecular description
of stemness. In evaluating this plan, we need ask two
questions. First, do stem cells really perform feats of
potency and self-renewal that set them apart? Second,
should we expect there to be a common molecular basis for
those behaviors?