Mitochondral DNA Mutations In Lung Cancer And Mitochodrial DNA Polymorphisms In Chinese Lung Cancer Patients.

Mitochondrion is the unique organell that contained DNA in mammalian cells. Mitochondrila DNA (mtDNA) possesses an independent genetic regulatory system. Human mtDNA is a 16,569-base pair double-stranded circular molecule, encoding two ribosomal RNAs (rRNA), 22 transfer RNAs (tRNAs), and 13 polypeptides of the respiratory chain. Because of the potential of being damaged by the reactive oxygen species produced in mitochondria, the deficiency of highly efficient DNA repair system, and the lack of DNA protection afforded by histone and chromatin structure, mtDNA has a very high mutation rate. When a mtDNA mutation arises, it creates an intracellular mixture of mutant and normal molecules called heteroplasmy. When all copies of mtDNA are identical at a given locus, this is termed homoplasmy. MtDNA mutations were related to a variety of disease, such as neurodegenerative disorders and cardiomyopathy.Over the past decade, a lot of homoplasmic mtDNA mutations have been identified in various tumors, including bladder cancer, head and neck cancer, pancreatic cancer, lung cancer, hepatocellular carcinoma, colorectal cancer, thyroid cancers, breast cancer and gastric carcinoma. However, the extent to which cancer is caused by or is a consequence of mitochondrial genomic...