This apparent correlation between Sox2 and Aldh1a1 was supported by the observation that ectopic Sox2 expression increased Aldh1a1 mRNA levels in sh-AhR but not in Aldh1a1-interfered melanoma cells (Fig. 4e), indicating that Sox2 could play a role in maintaining Aldh1a1 expression. This evidence concerns the gene SOX2 and melanoma.