Since we observed that NDUFB3 knockdown and overexpression were associated with downregulation and upregulation, respectively, of other subunits in complex I, II, III, IV, and V (Figure 3), the downregulation of other complex I subunit protein expressions in HCC can be secondary to the NDUFB3 downregulation. The gene discussed is NDUFB3; the disease is hepatocellular carcinoma.