In summary, the field of hepatic stem cell study has undergonetremendous growth during the past decade. The initial phaseof this research has focused on isolating and characterizingselect cellular populations, a critical first step. It is anticipatedthat over the next few years we will see an in-depth investigationof the hepatic stem/progenitor cell populations with respectto differentiation signals. A balance must be achieved betweendeveloping a critical mass of functional cells while controllingthe regenerative capacity of the progenitor cells . Furtherexploration into methods of transplantation and engraftmentof these cells will be required. As we move forward in the fieldof hepatic progenitor cell research, these hurdles must be overcomefor cell transplantation involving stem/progenitor cells tobecome a therapeutic possibility.