In support of the biological relevance of the transcriptional regulation of GLI1 by SOX2, we found a statistically significant correlation between SOX2 and GLI1 expression in a panel of metastatic melanoma cells (Pearson score R = 0.664, p = 0.036) (Fig. 1H; Supplementary Fig. 4a). This evidence concerns the gene GLI1 and melanoma.