SOX9 and melanoma: Although our previous studies in chick embryos demonstrated that overexpression of SOX9 was sufficient to induce ectopic Nedd9 expression [22], our data showed that moderate increase of SOX9 expression in SOX10 KD melanoma cells was not able to restore NEDD9 expression (Fig. 3c,d and Fig. 4a,b), raising the possibility that further elevation of SOX9 expression level might be required for the restoration of NEDD9 expression based on the previous findings that SOX9 acts in a dose-dependent manner [34, 35].