CD44 and cancer: Corresponding to the effects of circEPHB4 level on neurosphere formation, down‐regulating or up‐regulating circEPHB4 was associated with respectively reduced or increased levels of multiple biomarkers for cancer stemness, including surface expression of CD133 (as detected by flow cytometry; Fig. 2E,F), and cellular levels of Nestin, Oct4, Nanog, CD133 and CD44 (as detected by Western blotting; Fig. 2G,H).