ALDH1A1 and esophageal squamous cell carcinoma: The results showed that continuous cisplatin treatment induced the upregulation of CSC related transcription factors, including Nanog, Sox2, and Oct4 in TE-1 cells (Figure 3C) and increased the proportion of ALDH1 positive cells, i.e., ESCC stem cells (Yang et al., 2014; Figure 3D).