title: The mitochondrial DNA 4,977-bp deletion and its implication in copy number alteration in colorectal cancer.
abstract: BACKGROUND
  qualitative and quantitative changes in human mitochondrial DNA (mtDNA) have been implicated in various cancer types. A 4,977 bp deletion in the major arch of the mitochondrial genome is one of the most common mutations associated with a variety of human diseases and aging.
  
  
  METHODS
  we conducted a comprehensive study on clinical features and mtDNA of 104 colorectal cancer patients in the Wenzhou area of China. In particular, using a quantitative real time PCR method, we analyzed the 4,977 bp deletion and mtDNA content in tumor tissues and paired non-tumor areas from these patients.
  
  
  RESULTS
  we found that the 4,977 bp deletion was more likely to be present in patients of younger age (≤65 years, p = 0.027). In patients with the 4,977 bp deletion, the deletion level decreased as the cancer stage advanced (p = 0.031). Moreover, mtDNA copy number in tumor tissues of patients with this deletion increased, both compared with that in adjacent non-tumor tissues and with in tumors of patients without the deletion. Such mtDNA content increase correlated with the levels of the 4,977 bp deletion and with cancer stage (p < 0.001).
  
  
  CONCLUSIONS
  our study indicates that the mtDNA 4,977 bp deletion may play a role in the early stage of colorectal cancer, and it is also implicated in alteration of mtDNA content in cancer cells.
authors.affiliation: Zhejiang Provincial Key Laboratory of Medical Genetics, School of Laboratory Medicine of Wenzhou Medical College, Zhejiang 325035, PRChina.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: He
authors.forename: Lijun
authors.initials: L
authors.lastname: Shen
authors.forename: Hezhi
authors.initials: H
authors.lastname: Fang
authors.forename: Hezhongrong
authors.initials: H
authors.lastname: Nie
authors.forename: Tao
authors.initials: T
authors.lastname: Jin
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Wei
authors.forename: Yijuan
authors.initials: Y
authors.lastname: Xin
authors.forename: Yulin
authors.initials: Y
authors.lastname: Jiang
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Li
authors.forename: Guorong
authors.initials: G
authors.lastname: Chen
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lu
authors.forename: Yidong
authors.initials: Y
authors.lastname: Bai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D002681:China / Q000453:epidemiology; D015179:Colorectal Neoplasms / Q000235:genetics*; D056915:DNA Copy Number Variations / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D017384:Sequence Deletion / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D004273:DNA, Neoplasm