BACKGROUND We evaluated the feasibility of mitochondrial DNA (mtDNA) copy number measurement in dried blood spots (DBS), its comparability with measurement in whole blood samples, and stability of mtDNA copy number from DBS over time. METHODS Women in this pilot study were participants in the Sister Study, a large prospective cohort. Sister Study participants provided a whole blood sample and DBS at enrollment. A second DBS sample was collected 5-10 years later from a subcohort of women with and without an incident breast cancer diagnosis between collections. Among 54 women (27 with breast cancer, 27 without) we measured mtDNA copy number from whole blood at enrollment and from DBS at both time points. RESULTS The average age at enrollment was 58.7 years (range:50-69). Values of mtDNA copy number measured in whole blood samples and DBS from enrollment were moderately correlated (Spearman R=0.45;p=0.005). Stability of mtDNA copy number in DBS from the two time points was moderate overall (ICC=0.50) and similar between women with (ICC=0.50) and without (ICC=0.51) a breast cancer diagnosis between the two collections. CONCLUSIONS Our results suggest that measurement of mtDNA copy number in DBS is feasible and may be a valid alternative to measurement in whole blood samples.

中文翻译：

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干血斑中线粒体 DNA 拷贝数的测量：一项试点研究


背景我们评估了干血斑 (DBS) 中线粒体 DNA (mtDNA) 拷贝数测量的可行性、其与全血样本测量的可比性，以及 DBS 中 mtDNA 拷贝数随时间的稳定性。方法 这项试点研究中的女性是姐妹研究（一个大型前瞻性队列）的参与者。姐妹研究参与者在入组时提供了全血样本和 DBS。第二个 DBS 样本是在 5-10 年后从一组女性中收集的，这些女性在两次采集之间有或没有被诊断出乳腺癌。在 54 名女性（27 名患有乳腺癌，27 名未患乳腺癌）中，我们测量了入组时全血和两个时间点 DBS 的 mtDNA 拷贝数。结果 平均入组年龄为58.7岁（范围：50-69岁）。全血样本中测得的线粒体DNA拷贝数值与入组时的DBS值呈中度相关（Spearman R=0.45；p=0.005）。两个时间点的 DBS 中 mtDNA 拷贝数的稳定性总体上中等（ICC=0.50），并且在两个集合之间有（ICC=0.50）和没有（ICC=0.51）乳腺癌诊断的女性之间相似。结论 我们的结果表明，在 DBS 中测量 mtDNA 拷贝数是可行的，并且可能是全血样本测量的有效替代方法。