title: The mitochondrial ATPase6 gene is more susceptible to mutation than the ATPase8 gene in breast cancer patients.
abstract: BACKGROUND
  Breast cancer is the most common malignancy in women throughout the world. Mitochondria play important roles in cellular energy production, free radical generation and apoptosis. Identification of mitochondrial DNA mutations and/or polymorphisms as cancer biomarkers is rapidly developing in molecular oncology research.
  
  
  METHODS
  In this study, the DNA alterations of the mitochondrial ATPase 6 and 8 genes were investigated in 49 breast cancer patients using PCR amplification and direct DNA sequencing on mtDNA. A possible association between these variants and tumorigenesis was assessed. Furthermore, the impact of non-synonymous substitutions on the amino acid sequence was evaluated using the PolyPhen-2 software.
  
  
  RESULTS
  Twenty eight distinct somatic mitochondrial DNA variants were detected in tumor tissues but not in the corresponding adjacent non-tumor tissues. Among these variants, 9 were observed for the first time in breast cancer patients. The mtDNA variants of A8384 (T7A), T8567C (I14T), G8572A (G16S), A9041G (H172R) and G9055A (A177T) showed the most significant effects probably due to damaging changes to the resulting protein. Furthermore, non-synonymous amino acid changing variants were more frequent in the ATPase6 gene compared to the ATPase8 gene.
  
  
  CONCLUSIONS
  Our results showed that the ATPase6 gene is more susceptible to variations in breast cancer and may play an important role in tumorigenesis by changing the energy metabolism level in cancer cells.
authors.forename: Massoud
authors.initials: M
authors.lastname: Ghaffarpour
authors.forename: Reza
authors.initials: R
authors.lastname: Mahdian
authors.forename: Forouzandeh
authors.initials: F
authors.lastname: Fereidooni
authors.forename: Behnam
authors.initials: B
authors.lastname: Kamalidehghan
authors.forename: Nasrin
authors.initials: N
authors.lastname: Moazami
authors.affiliation: Medical Genetics Department, National Institute for Genetic Engineering & Biotechnology, Tehran, Iran. massoudh@nigeb.ac.ir.
authors.forename: Massoud
authors.initials: M
authors.lastname: Houshmand