Subsequently, we reviewed the UALCAN online tool (http://ualcan.path.uab.edu/cgi-bin/ualcan-res.pl) and found that PKR expression was upregulated in ESCC tissues (Supplementary Fig. 3), indicating the carcinogenic effects of PKR in ESCC. The gene discussed is EIF2AK2; the disease is esophageal squamous cell carcinoma.