Association of leukocyte mitochondrial DNA copy number with colorectal cancer risk: results from the Shanghai Women's Health Study
Couplée aux données de la cohorte "Shanghai Women's Health Study" et portant sur 444 cas et 1 423 témoins, cette étude évalue l'association entre le nombre de copies d'ADN dans les mitochondries des leucocytes et le risque de cancer colorectal
Background: Mitochondria play an important role in cellular energy metabolism, free radical production, and apoptosis and thus may be involved in cancer development. Methods: We evaluated mtDNA copy number in peripheral leukocytes in relation to CRC risk in a case-control study of 444 CRC cases and 1,423 controls nested in the Shanghai Women's Health Study, a population-based, prospective cohort study. Relative mtDNA copy number was determined by a quantitative real-time PCR assay using peripheral leukocyte DNA samples collected at the time of study enrollment, prior to cancer diagnosis. Results: We found that baseline mtDNA copy number was lower among women who subsequently developed CRC (geometric mean = 0.277, 95% CI: 0.269-0.285) than among women who remained cancer-free (geometric mean = 0.288, 95% CI: 0.284-0.293; P=0.0153). Multivariate adjusted odds ratios (ORs) were 1.26 (95% CI: 0.93-1.70) and 1.44 (95% CI: 1.06-1.94) for the middle and lower tertiles of mtDNA copy number, respectively, compared with the upper tertile (highest mtDNA copy number; P for trend=0.0204). The association varied little by the interval between blood collection and cancer diagnosis. Conclusions: Our data suggest that mtDNA copy number measured in peripheral leukocytes may be a potential biomarker useful for CRC risk assessment. Impact: If confirmed, mtDNA copy number measured in peripheral leukocytes may be a biomarker useful for colorectal cancer risk assessment.