Up to now, our and other groups have isolated and characterized ESCC cancer stem-like cells (ECSLCs) using aldehyde dehydrogenase 1A1 (ALDH1A1) [4], CD44 [5], p75NTR [6, 7] and CD90 [8] as markers. This evidence concerns the gene ALDH1A1 and esophageal squamous cell carcinoma.