GRM4 and esophageal squamous cell carcinoma: There were four mRNAs not only upregulated in ESCC compared with para-cancer tissues but also in Fu-High compared with Fu-Low: C-Type Lectin Domain Family 12 Member A (CLEC12A), Glutamate Metabotropic Receptor 4 (GRM4), Protein Arginine Methyltransferase 8 (PRMT8), and Peptide YY 2 (PYY2) (Fig. 1J).