title: Pooled analysis of mitochondrial DNA copy number and lung cancer risk in three prospective studies.
abstract: BACKGROUND
  We previously reported that higher levels of mitochondrial DNA copy number (mtDNA CN) were associated with lung cancer risk among male heavy smokers (i.e., ≥20 cigarettes per day) in the Alpha-Tocopherol Beta-Carotene (ATBC) study. Here, we present two additional prospective investigations nested in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial and the Shanghai Women's Health Study (SWHS), and pooled with previously published data from ATBC.
  
  
  METHODS
  All DNA were extracted from peripheral whole blood samples using the phenol-chloroform method, and mtDNA CN was assayed by fluorescence-based qPCR. Multivariate unconditional logistic regression models were used to estimate ORs and 95% confidence intervals for the association of mtDNA CN and lung cancer risk.
  
  
  RESULTS
  Overall, mtDNA CN was not associated with lung cancer risk in the PLCO, SWHS, or pooled populations (all P trends > 0.42, P heterogeneity = 0.0001), and mtDNA CN was inversely associated with lung cancer risk among male smokers in PLCO, the opposite direction observed in ATBC. In addition, the mtDNA CN association observed among male heavy smokers in ATBC was the opposite direction in PLCO.
  
  
  CONCLUSIONS
  mtDNA CN was not consistently associated with lung cancer risk across three prospective study populations from Europe, Asia, and the United States.
  
  
  CONCLUSIONS
  This pooled study suggests no consistent association between prediagnostic mtDNA CN levels and lung cancer risk across several populations. Cancer Epidemiol Biomarkers Prev; 23(12); 2977-80. ©2014 AACR.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. christopher.kim@nih.gov.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kim
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Bassig
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Wei Jie
authors.initials: WJ
authors.lastname: Seow
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Purdue
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Wen-Yi
authors.initials: WY
authors.lastname: Huang
authors.affiliation: Neurology and Vascular and Genomic Center, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Chin-San
authors.initials: CS
authors.lastname: Liu
authors.affiliation: Neurology and Vascular and Genomic Center, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Wen-Ling
authors.initials: WL
authors.lastname: Cheng
authors.affiliation: Neurology and Vascular and Genomic Center, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Ta-Tsung
authors.initials: TT
authors.lastname: Lin
authors.affiliation: Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors.forename: Yong-Bing
authors.initials: YB
authors.lastname: Xiang
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Bu-Tian
authors.initials: BT
authors.lastname: Ji
authors.affiliation: Shanghai Cancer Institute, Shanghai, China.
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.affiliation: University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Wong-Ho
authors.initials: WH
authors.lastname: Chow
authors.affiliation: Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Satu
authors.initials: S
authors.lastname: Männistö
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Weinstein
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Demetrius
authors.initials: D
authors.lastname: Albanes
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.affiliation: Albert Einstein College of Medicine, Yeshiva University, Bronx, New York.
authors.forename: H Dean
authors.initials: HD
authors.lastname: Hosgood
authors.affiliation: Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii.
authors.forename: Unhee
authors.initials: U
authors.lastname: Lim
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Rothman
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lan
mesh_terms: D056915:DNA Copy Number Variations; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics*; D011446:Prospective Studies; D012307:Risk Factors