ADRA2C and hepatocellular carcinoma: By performing the univariable Cox survival analysis of 115 NRGs in the ICGC-LIRI-JP dataset, nine critical genes (CHRNA3, GABRR2, GRM2, CHRNG, GRIA2, GRM6, GRIN2B, ADRA2C, and GRID2), which were significantly correlated with the OS of the patients with HCC, were identified (Figure 2A).