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Journal of Oncology
Volume 2011, Article ID 496189, 10 pages
http://dx.doi.org/10.1155/2011/496189
Research Article

Mitochondrial DNA Content Varies with Pathological Characteristics of Breast Cancer

1Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, NAB 2015, Houston, TX 77030, USA
2GeneDx, Inc., 207 Perry Parkway, Gaithersburg, MD 20877, USA
3Department of Pathology, Changhua Christian Hospital, ChangHua, Taiwan
4Department of Surgery, Cardinal Tien Hospital, Taipei, Taiwan
5School of Medicine, Fu Jen Catholic University, Tio, Taipei, Taiwan
6Department of Pathology, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
7Division of Biostatistics, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
8Cancer Prevention and Population Science Program, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA

Received 2 March 2011; Revised 4 July 2011; Accepted 6 August 2011

Academic Editor: K. K. Singh

Copyright © 2011 Ren-Kui Bai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Changes in mitochondrial DNA (mtDNA) content in cancers have been reported with controversial results, probably due to small sample size and variable pathological conditions. In this study, mtDNA content in 302 breast tumor/surrounding normal tissue pairs were evaluated and correlated with the clinico-pathological characteristics of tumors. Overall, mtDNA content in tumor tissues is significantly lower than that in the surrounding normal tissues, . MtDNA content in tumor tissues decreased with increasing tumor size. However, when the tumor is very large (>50 cm3), mtDNA content started to increase. Similarly, mtDNA content decreased from grades 0 and I to grade II tumors, but increased from grade II to grade III tumors. Tumors with somatic mtDNA alterations in coding region have significantly higher mtDNA content than tumors without somatic mtDNA alterations ( ). Tumors with somatic mtDNA alterations in the D-Loop region have significantly lower mtDNA content ( ). Patients with both low and high mtDNA content in tumor tissue have significantly higher hazard of death than patients with median levels of mtDNA content. mtDNA content in tumor tissues change with tumor size, grade, and ER/PR status; significant deviation from the median level of mtDNA content is associated with poor survival.