Functional Role of Mitochondrial DNA in Cancer Progression

Mitochondrial DNA (mtDNA) has been identified as a significant genetic biomarker in disease, cancer and evolution. Mitochondria function as modulators for regulating cellular metab-olism. In the clinic, mtDNA variations (mutations/single nucleotide polymorphisms) and dysreg-ulation of mitochondria-encoded genes are associated with survival outcomes among cancer pa-tients. On the other hand, nuclear-encoded genes have been found to regulate mitochon-dria-encoded gene expression, in turn regulating mitochondrial homeostasis. These observations suggest that the crosstalk between the nuclear genome and mitochondrial genome is important for cellular function. Therefore, this review summarizes the significant mechanisms and functional roles of mtDNA variations (DNA level) and mtDNA-encoded genes (RNA and protein levels) in cancers and discusses new mechanisms of crosstalk between mtDNA and the nuclear genome.