EGF and cancer: In order to generate a primary culture of floating spheroids with enriched cancer stem cells, we placed MKN-45 cells at a density of 10000 cells/ml in serum-free RPMI that contained B27 (1:50, Gibco, USA), 20 ng/ml of basic fibroblast growth factor (bFGF, Royan Institute, Iran), and epidermal growth factor (EGF, Royan Institute, Iran) in T-25 non-adhesive poly(2-hydroxyethyl methacrylate) (poly-HEMA, Sigma, USA) coated flasks.