To determine whether ERK1/2 pathway took part in this process, we further evaluated the expression levels of ERK1/2 and phosphorylation of ERK1/2 (p-ERK1/2) in TPA-treated cells, and found that p-ERK1/2 was enhanced after TPA treatment in both ESCC cell lines, while total ERK1/2 did not. This evidence concerns the gene MAPK3 and esophageal squamous cell carcinoma.