CD44 and head and neck squamous cell carcinoma: Furthermore, we found that the protein expression of TRAF6 was statistically associated with those CSC and EMT markers in mice SCCHN tissues (CD44, P < 0.001, r = 0.8573; KLF4, P < 0.001, r = 0.7891; ALDH1, P < 0.001, r = 0.7411; SOX2, P < 0.001, r = 0.6532; Slug, P < 0.001, r = 0.6857; Vimentin, P < 0.001, r = 0.6617; Fig. 4D) by Spearman rank correlation coefficient test and linear tendency test.