Abstract 1126: Mitochondrial DNA copy number and colorectal cancer risk: Results from the Shanghai Women's Health Study

Abstract

Abstract Mitochondria play an important role in cellular energy metabolism, free radical generation, and apoptosis. Cumulative evidence suggests that mtDNA copy number may be a biomarker for cancer risk. Using a nested case-control design, we evaluated mtDNA copy number in peripheral blood cells in relation to colorectal cancer risk. Included in the study were 436 colorectal cancer cases and 881 matched controls identified from the Shanghai Woman's Health Study, a population-based, prospective cohort study conducted among Chinese women. Relative mtDNA copy number was determined in triplicate by a quantitative real-time PCR assay using peripheral blood cell DNA samples collected at the time of study enrollment, prior to cancer diagnosis. Baseline levels of mtDNA copy number were lower among women who subsequently developed colorectal cancer (geometric mean = 0.271, 95% CI: 0.263-0.279) than those who remained cancer-free (geometric mean = 0.281, 95% CI: 0.275-0.288) (P=0.0274). Multivariate adjusted odds ratios were 1.15 (95% CI: 0.80-1.65), 1.12 (95% CI: 0.78-1.60) and 1.58 (95% CI: 1.10-2.26) for third to the first quartile of mtDNA copy numbers, respectively, comparing with the highest quartile (P for trend = 0.0135). The association varied little by the interval between blood draw and cancer diagnosis. To our knowledge, this is the first large prospective study evaluating the association of mtDNA copy number with subsequent risk of developing colorectal cancer. Our data suggests that decreased mtDNA copy number may be associated with increased colorectal cancer risk, and mtDNA copy number measured in peripheral blood cells may be a potential biomarker useful for colorectal cancer risk assessment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1126. doi:1538-7445.AM2012-1126