One of the established clones (C44Mab−46; IgG1, kappa) reacted with CD44 standard isoform (CD44s)−overexpressed Chinese hamster ovary−K1 cells (CHO/CD44s) or esophageal squamous cell carcinoma (ESCC) cell lines (KYSE70 and KYSE770). This evidence concerns the gene CD44 and esophageal squamous cell carcinoma.