Disruption of complex II leads to changes in the TCA cycle, but also to changes in oxidative phosphorylation in the form of upregulation of complex I. Pang et al showed that in tumor tissue and in an SDHB‐ knockdown mouse cell line, complex I components and activity are upregulated.107 Consequently, the quantity of NAD+ in tumor tissue was 2.7‐fold higher in cluster I than in cluster II tumors. The gene discussed is SDHB; the disease is neoplasm.