Mitochondrial DNA Copy Number Variations in Gastrointestinal Tract Cancers: Potential Players

Alterations of mitochondria have been linked to several cancers. Also, the mitochondrial DNA copy number (mtDNA-CN) is altered in various cancers, including gastrointestinal tract (GIT) cancers, and several research groups have investigated its potential as a cancer biomarker. However, the exact causes of mtDNA-CN variations are not yet revealed. This review discussed the conceivable players in this scheme, including reactive oxygen species (ROS), mtDNA genetic variations, DNA methylation, telomere length, autophagy, immune system activation, aging, and infections, and discussed their possible impact in the initiation and progression of cancer. By further exploring such mechanisms, mtDNA-CN variations may be effectively utilized as cancer biomarkers and provide grounds for developing novel cancer therapeutic agents.