MT-ND5 and cancer: Regardless, MT-ND5 encodes a core subunit of Complex I, essential for electron transport from NADH to ubiquinone in the mitochondrial respiratory chain, so that variants in this gene and others related to this process may lead to impairment in OXPHOS and an increase of reactive oxygen species (ROS) generation, which can contribute to cancer proliferation and metastasis36,37.