We also analyzed the copy numbers of SOX2 in TCGA head and neck dataset from http://xena.uscs.edu/public-hubs, and found that compared with normal nasopharyngeal carcinoma tissues, 86% (450/524) tumors were amplified (log2 > 0, tumor versus normal) (Fig. 1b). This evidence concerns the gene SOX2 and nasopharyngeal carcinoma.