SOX2 and esophageal squamous cell carcinoma: Analysis of the relationship between expression of Shh and Sox2 and overall survival (OS) of the patients showed that the expression of Shh was marginally related to the OS of platinum-treated ESCC patients (P = 0.07, Figure 1C left), whereas Sox2 showed a significant correlation with the patients’ OS (P = 0.03, Figure 1C middle).