COA6 and hepatocellular carcinoma: Whereas the gene expressions of ATP7A, SLC25A3, SCO2, COA6, TMEM199, ATP6AP1, LIPT1, DLAT, PDHA1, MTF1, ACP1, FDX2, NUBP2, CIAPIN1, ISCA2, and NDOR1 in HCC tissues were prominently higher than their surrounding tissues, and the differences were all statistically significant (P < 0.001, Figure 2).