Expression of MOR mRNA was significantly upregulated in clear cell renal cell carcinoma and pancreatic ductal adenocarcinoma versus healthy tissue (Fig. S1E-F), and increased MOR levels were also associated with patient survival/tumor recurrence in squamous cell lung carcinoma, esophageal squamous cell carcinoma, and colon adenocarcinoma (Fig. S1G-I). This evidence concerns the gene OPRM1 and esophageal squamous cell carcinoma.