To confirm the possible role of the ERK1/2 pathway in the stemness of HNSCC, CD44(+)-SCC-15 cells with sh.ERK1/2 or sh.Scr were injected into the flanks of immunodeficient mice; knockdown was confirmed by western blotting (Fig. 5a). Here, MAPK3 is linked to head and neck squamous cell carcinoma.