B49
A high-throughput method for measuring mean telomere length and its application to cancer susceptibility studies
Karen A. Pooley1, Manjinder S. Sandhu2, Bruce A.J. Ponder3, Douglas F. Easton1, Alison M. Dunning4
1CR_UK Genetic Epidemiology Unit, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK, 2Department of Public Health, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK, 3Department of Oncology, CR_UK Cambridge Research Institute, University of Cambridge, Cambridge, UK, 4Department of Oncology, Strangeways Research Laboratory, University of Cambridge, Cambridge, UK
Background
Human chromosomes are capped and stabilised by telomeres, predominantly formed from several thousand tandem repeats of a (TTAGGG)n sequence motif. This protects against chromosome ends being recognised as broken DNA in need of double-strand-break repair and prevents the fusion of one chromosome to another, thus helping maintain genome integrity. Telomeres tend to shorten with each cell division, resulting in a progressive reduction in mean telomere length per year, which accelerates over the age of 50 years. Previous studies have indicated that individuals with relatively short mean telomere lengths may have an increased risk of mortality from multiple diseases, including cancer.
Method
We have adapted a previously-published Real Time PCR-based technique into a simple, high-throughput assay for mean telomere length in DNA extracted from whole blood. This technique has been validated using a ‘gold standard’ non-radioactive Southern Blotting method in a sub-population of the DNA samples used. Our assay is being run across several sample sets, including prospectively and retrospectively collected cancer case-control studies.
Results
This assay is reproducible, with a correlation of >98% between repeated measurements on the same subject. In multiple studies, it demonstrates the expected reduction in mean telomere length with age (mean percentage reduction per year = 0.3, 95% Confidence Intervals (0.08 – 0.6), P=0.008) and displays strong heritability between siblings.
Conclusion
We have validated a robust, high-throughput method for measuring mean telomere length. This method is being used to test the hypothesis that short mean telomere length is associated with increased susceptibility to common cancers.
