title: Decreased mitochondrial DNA content in blood samples of patients with stage I breast cancer.
abstract: BACKGROUND
  Alterations of mitochondrial DNA (mtDNA) have been implicated in carcinogenesis. We developed an accurate multiplex quantitative real-time PCR for synchronized determination of mtDNA and nuclear DNA (nDNA). We sought to investigate whether mtDNA content in the peripheral blood of breast cancer patients is associated with clinical and pathological parameters.
  
  
  METHODS
  Peripheral blood samples were collected from 60 patients with breast cancer and 51 age-matched healthy individuals as control. DNA was extracted from peripheral blood for the quantification of mtDNA and nDNA, using a one-step multiplex real-time PCR. A FAM labeled MGB probe and primers were used to amplify the mtDNA sequence of the ATP 8 gene, and a VIC labeled MGB probe and primers were employed to amplify the glyceraldehyde-3-phosphate-dehydrogenase gene. mtDNA content was correlated with tumor stage, menstruation status, and age of patients as well as lymph node status and the expression of estrogen receptor (ER), progesterone receptor (PR) and Her-2/neu protein.
  
  
  RESULTS
  The content of mtDNA in stage I breast cancer patients was significantly lower than in other stages (overall P = 0.023). Reduced mtDNA was found often in post menopausal cancer group (P = 0.024). No difference in mtDNA content, in regards to age (p = 0.564), lymph node involvement (p = 0.673), ER (p = 0.877), PR (p = 0.763), and Her-2/neu expression (p = 0.335), was observed.
  
  
  CONCLUSIONS
  Early detection of breast cancer has proved difficult and current detection methods are inadequate. In the present study, decreased mtDNA content in the peripheral blood of patients with breast cancer was strongly associated with stage I. The use of mtDNA may have diagnostic value and further studies are required to validate it as a potential biomarker for early detection of breast cancer.
authors.affiliation: Department of Surgical Oncology, First Affiliated Hospital of Medical College, Xi'an Jiaotong University, 710061 Xi'an, PR China. xiapeng30000@yahoo.com.cn
authors.forename: Peng
authors.initials: P
authors.lastname: Xia
authors.forename: Han-Xiang
authors.initials: HX
authors.lastname: An
authors.forename: Cheng-Xue
authors.initials: CX
authors.lastname: Dang
authors.forename: Ramin
authors.initials: R
authors.lastname: Radpour
authors.forename: Corina
authors.initials: C
authors.lastname: Kohler
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Fokas
authors.forename: Rita
authors.initials: R
authors.lastname: Engenhart-Cabillic
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Holzgreve
authors.forename: Xiao Yan
authors.initials: XY
authors.lastname: Zhong
mesh_terms: D001943:Breast Neoplasms / Q000097:blood* / Q000235:genetics* / Q000473:pathology; D004272:DNA, Mitochondrial / Q000097:blood*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004272:DNA, Mitochondrial