NDUFB3 is a subunit of ETC complex I. Our discovery of NDUFB3’s role in maintaining ROS balance in HCC supports the previously proposed NDUFB3 function in determining normal complex I activity and regulating ROS production.25–27 In addition to the NDUFB3, many other ETC complex I subunits also display reduced protein expressions in HCC (Supplemental Figure S2, http://links.lww.com/HC9/A825). This evidence concerns the gene NDUFB3 and hepatocellular carcinoma.