This observation appears contradictory to the numerous tumor-specific mtDNA mutations, including deleterious ones, detected in association tests utilizing sequencing data from established cancer samples.33,39 Based on our observations that MT-ND5 mutations are oncogenic in non-cancerous cells, we propose that the mtDNA mutations observed in cancer tissues may be remnants from the initial stages of oncogenesis, where mtDNA mutations and mitochondrial dysfunction drive the onset of cancer. The gene discussed is MT-ND5; the disease is cancer.