We also showed that NDUFB3 in thyroid cancer cells upregulated MT-ND5 subunit, increased complex I activity and ATP levels, enhanced mitoROS generation, and improved mitochondrial respiration, despite no changes in mitochondrial number (Figures 4(d)–4(g); Supplementary Figures 4 and Figure 10). Here, MT-ND5 is linked to thyroid cancer.