Next, we investigated the phosphorylation levels of STAT3 and ERK1/2 in 12 ESCC tissue and the results confirmed that the expression of pERK1/2 and pSTAT3 had an inverse correlation (r = −0.5847, P = 0.0459) (Fig. 2H). This evidence concerns the gene MAPK3 and esophageal squamous cell carcinoma.