J Cancer Res Clin Oncol (2009) 135:983–989 DOI 10.1007/s00432-008-0533-9 123 ORIGINAL PAPER Mitochondrial DNA content in paired normal and cancerous breast tissue samples from patients with breast cancer Alex Xiu-Cheng Fan · Ramin Radpour · Mahdi Montazer Haghighi · Corina Kohler · Peng Xia · Sinuhe Hahn · Wolfgang Holzgreve · Xiao Yan Zhong Received: 19 May 2008 / Accepted: 8 December 2008 / Published online: 6 January 2009  Springer-Verlag 2008 Abstract Introduction We develop a multiplex quantitative real- time PCR for synchronized analysis of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) to investigate relative mtDNA abundance in paired normal and cancerous breast tissues. Materials and methods The amounts of nDNA and mtDNA in 102 tissue samples were quantiWed for both glyceraldehype-3-phosphodehydrogenase (GAPDH) gene and mtDNA encoded ATPase (MTATP) 8 gene. The aver- age threshold cycle (Ct) number values of the nDNA and mtDNA were used to calculate relative mtDNA content in breast tissues. Results The median delta Ct (Ct) and the median mtDNA content for normal and cancerous breast tissues were 6.73 and 2.54, as well as 106.50 and 5.80 (P = 0.000, respectively). The mtDNA content was decreased in 82% of cancerous breast tissues compared with the normal ones. The changes were associated with hormone receptor status. Conclusion Our Wnding suggests that decreased mtDNA content in breast cancer may have diagnostic and prognos- tic value for the disease. Keywords Quantitative alteration · Mitochondrial DNA · Breast cancer · Breast tissue Introduction Human cells have a nuclear genome and additional cyto- plasmic genomes that are compartmentalised in the mito- chondria. In comparison to nuclear genomic DNA, mitochondrial DNA (mtDNA) reveals high mutation rates caused by constant exposure to mutagenic oxygen radicals and lacks the protective mechanisms of DNA repair. These properties of mtDNA suggest their potential importance in ageing, apoptosis and especially carcinogenesis (Zhang and Qi 2008; Zhang et al. 2008). Qualitative aberrations of mtDNA, such as mutations, have been found in solid tumours, such as colon, stomach, liver, kidney, bladder, prostate, skin and lung cancer (Copeland et al. 2002; Penta et al. 2001), and in haematological malig- nancies, such as leukaemia and lymphoma (Fontenay et al. 2006). Quantitative aberrations of mtDNA have been observed in various sample types from patients with cancers (Mambo et al. 2005). While increased mtDNA content has been found in prostate (Mizumachi et al. 2008a), head and neck (Kim et al. 2004), endometrial adenocarcinoma (Wang et al. 2005), etc., reduced mtDNA content in renal (Meierhofer et al. 2004) and liver cancers (Yin et al. 2004) has been reported. Because of these mutations and the quantitative aberra- tions involved in the development of human cancers, mtDNA may have promising clinical applications for can- cers (Jiang et al. 2005; Jain 2007). Decreased mitochondrial DNA copy number is correlated with tumour progression and prognosis in Chinese breast cancer patients (Yu et al. 2007). Increased mtDNA content in saliva is associated A. X.-C. Fan · R. Radpour · C. Kohler · P. Xia · S. Hahn · W. Holzgreve · X. Y. Zhong (&) Laboratory for Prenatal Medicine and Gynecologic Oncology, Department of Biomedicine, Women’s Hospital, University of Basel, Hebelstrasse 20, Room Nr. 416, 4031 Basel, Switzerland e-mail: xzhong@uhbs.ch M. M. Haghighi Azad University, East of Tehran Branch, Tehran, Iran W. Holzgreve University Medical Center, University of Freiburg, Hugstetter Str. 49, 79106 Freiburg, Germany