SOX2 and esophageal squamous cell carcinoma: In addition, the ATF more significantly suppressed cell viability and colony formation of SOX2-expressing lung and esophageal SCC cells compared to shSOX2, whereas little CDKN1A expression was induced after Ad-ATF/SOX2 infection in SOX2 negative lung SCC cells and normal human cells HUVEC and NHLF (Supplementary Figure 3A).