(4) Mitochondria are in charge of energy metabolism and tumor cell proliferation: Recent studies have illustrated that tumor cells could promote the generation of glutamine by oxidizing glucose-derived pyruvate through the pyruvate dehydrogenase (PDH)-dependent pathway in mitochondria, which is crucial for tumor growth (Woolbright et al., 2019; Khan et al., 2020; Nie et al., 2020). This evidence concerns the gene PDP1 and neoplasm.