In addition, metallothionein (MT) family proteins, such as MT-2A, are highly expressed in cancer-associated fibroblasts, and the methylation of MT-1 genes (MT-1A, MT-1M, and others) is significantly higher in ESCC samples than that in normal esophageal mucosa tissue [130, 131]. Here, MT1A is linked to esophageal squamous cell carcinoma.