*2.10. Tumoursphere-Formation Assay*

After producing a single-cell suspension, the cells were cultured in ultra-low attachment 6-well or 96-well plates in medium consisting of DMEM/F12 supplemented with 2% B27 supplements (Invitrogen), 10 ng mL−<sup>1</sup> bFGF (Peprotech, Rocky Hill, NJ, USA) and 10 ng/mL EGF. The cells were cultured for 7 days, and the morphology and size of sphere were determined using an Olympus IX71 fluorescence microscope (Olympus).
