Mitochondrial copy number is associated with colorectal cancer risk
Cancer Epidemiology, Biomarkers & Prevention, 07/16/2012
Thyagarajan B et al. – This is the first prospectively designed study to show a U-shaped association between the relative mtDNA copy number and risk of colorectal cancer.Methods
- We evaluated the association between mtDNA copy number in peripheral blood and colorectal cancer risk in a nested case-control study of 422 colorectal cancer cases (168 cases with pre-diagnostic blood and 254 cases with post-diagnostic blood) and 874 controls who were free of colorectal cancer among participants of the Singapore Chinese Health Study.
- The relative mtDNA copy number was measured using real time PCR.
- Unconditional logistic regression methods were employed to examine the association between mtDNA copy number and colorectal cancer risk.
- There was a U-shaped relationship between the relative mtDNA copy number and colorectal cancer risk.
- Compared with the 2nd quartile, the odds ratios (95% confidence intervals) for subjects in the lowest and highest quartiles of relative mtDNA copy numbers were 1.81 (1.13-2.89) and 3.40 (2.15-5.36), respectively (Pcurvilinearity <0.0001).
- This U-shaped relationship was present in both men and women, similar for colon cancer and rectal cancer, and independent of the timing of blood draw with regards to cancer diagnosis.