As shown in Figure 5A, the fraction of CD44+CD133+ tumor-initiating Caco-2 cells in the sorted CD44+CD133+ subpopulation was about 87% (middle panel), and less than 2% of the isolated ΔCD44+CD133+ subpopulation was tumor-initiating CD44+CD133+ cells (bottom panel), indicating that both populations of Caco-2 cells were isolated successfully. Here, PROM1 is linked to neoplasm.