To determine the mechanism by which this occurs, we expanded primary culture of hepatoblasts enriched for progenitor markers CD133 and CD49f from embryonic day (E) 12.5 fetal liver and an established tumor initiating stem cell line from Mat1a−/− livers in media conditioned with recombinant (r) FGF10 or rFGF7. The gene discussed is PROM1; the disease is neoplasm.