SLC6A3 and hepatocellular carcinoma: In TCGA-HCC cohort, the expression of GAGE2D, PDE6A, GABRR1, DCAF8L1, DPYSL4, SLC6A3, MMP3, RIBC2, KCNH2, HTRA3, and PDX1 remarkably increased in the high OAG score group, and the expression of each OAG was positively associated with the OAG score, whereas the expression of ATHL1, PRTG, SHC4, C21orf29, SMIM32, and C1orf133 (ncRNA) elevated in the low OAG score group, and their expression was negatively associated with the OAG score (Figures 4A, B).