Flow cytometric analyses of cultured spheroid cells show that CD133+/EpCAM+ cells composed 33.2% of the total cells (Fig. 1D; right panel), suggesting that CD133+/EpCAM+ cells were enriched approximately 5-fold in tumor spheroid culture compared to 4–6% of CD133+/EpCAM+ cells in both the original patient sample and the xenograft tumors (Fig. 1B and data not shown, respectively). Here, PROM1 is linked to neoplasm.