title: Tandem duplication/triplication correlated with poly-cytosine stretch variation in human mitochondrial DNA D-loop region.
abstract: Somatic mutations in the mitochondrial DNA (mtDNA) displacement loop (D-loop) region have been frequently detected in various human cancers. In a previous study, we identified a polyplasmic 260-bp tandem duplication and triplication mutation in the mtDNA D-loop of one gastric cancer. In the present study, we adopted a more sensitive back-to-back polymerase chain reaction method to screen for this 260-bp tandem duplication/triplication in 197 cancers and their adjacent non-cancerous tissues. Nine samples of primary cancer (4.6%) were found to harbor the tandem duplication/triplication and these were made up of four out of 31 (12.9%) gastric cancers, two out of 45 (4.4%) breast cancers, two out of 56 (3.6%) hepatocellular cancers and one out of 32 (3.1%) colon cancers, but no tandem duplication/triplication was present in any of 33 lung cancers. We also found an expanded and polyplasmic poly-cytosine (poly-C) stretch around nucleotide position (np) 568 in eight of the 197 (4.1%) cancer patients. All the eight cancer samples carried the 260-bp tandem duplication/triplication. In addition, we detected the np 568 poly-C length variations in 11 of 234 (4.7%) peripheral blood samples of non-cancer population and the 260-bp tandem duplication in nine of the 11 cases with the np 568 poly-C length variations. These observations suggest that the occurrence of the tandem duplication/triplication in mtDNA D-loop is not specific for cancer tissues, but highly associated with the poly-C length variations around np 568.
authors.affiliation: Department and Institute of Pharmacology, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.
authors.forename: Wen-Yi
authors.initials: WY
authors.lastname: Hung
authors.forename: Jin-Ching
authors.initials: JC
authors.lastname: Lin
authors.forename: Liang-Ming
authors.initials: LM
authors.lastname: Lee
authors.forename: Chew-Wun
authors.initials: CW
authors.lastname: Wu
authors.forename: Ling-Ming
authors.initials: LM
authors.lastname: Tseng
authors.forename: Pen-Hui
authors.initials: PH
authors.lastname: Yin
authors.forename: Chin-Wen
authors.initials: CW
authors.lastname: Chi
authors.forename: Hsin-Chen
authors.initials: HC
authors.lastname: Lee
mesh_terms: D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D009154:Mutation; D009369:Neoplasms / Q000235:genetics*; D009690:Nucleic Acid Conformation; D011066:Poly C / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction
chemical_list: D004272:DNA, Mitochondrial; D004273:DNA, Neoplasm; D011066:Poly C