CD44 and neoplasm: Whereas control Luciferase-targeted shRNA tumors were significantly enriched for ESA+CD44+CD166+ cells in CPA- versus vehicle-treated mice (n≥5, *P = 0.0002), both CoCSC and NTG cells from ALDH1A1-targeted shRNA containing tumor cells appeared equally sensitive to CPA, as the frequency of CoCSC was no different (Figure 8C).