According to the analysis of TCGA-ESCA data, we found that the expression of serine hydroxymethyltransferases 1, 2 (SHMT1, SHMT2) and glycine decarboxylase (GLDC), which catalyze the conversion of serine to glycine, were upregulated in ESCC cancer tissues compared with normal tissues (Figure 4B). This evidence concerns the gene SHMT2 and esophageal squamous cell carcinoma.