SOX10 and melanoma: In agreement with previous observations, we observed a pronounced elevation of p21 protein upon SOX10 KD in both A375M and WM266–4 melanoma cells compared to the scramble control, whereas increased p21 expression was alleviated by SOX9 KD (Fig. 3j), indicating that upregulation of endogenous SOX9 by SOX10 KD is required for the induction of p21 expression.