Cells were resuspended in PBS and incubated with FcR blocking reagent (Miltenyi Biotec, Germany) for 10 min. Then cells were stained with the directly conjugated monoclonal antibodies, anti-human CD133-PE, anti-human IgG-PE isotype (Miltenyi Biotec, Germany), anti-human EpCAM-APC, anti-human IgG-APC isotype (R&D, USA) for 30-40 min in 4ºC. IgG isotype control was incubated in parallel. Flow cytometry analysis was performed on Accuri C6 (BD Biosciences, CA) using CFlow (BD Biosciences, CA) software. Cell sorting was performed on BD FACS Aria I (BD Biosciences, CA) using FlowJo (Tree Star, Oregon) software. Sorted cells were cultured in DMEM supplemented with 15% FBS for 7 days, then detected again by flow cytometry.