Authors' Affiliations: Departments of Laboratory Medicine and Pathology, Health Sciences Research, and Gastroenterology, Mayo Clinic College of Medicine; Mayo Clinic Cancer Center, Biomedical Statistics and Informatics, Mayo Clinic College of Medicine, Rochester, Minnesota; Departments of Population Health Sciences, and Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; University of Michigan, Ann Arbor, Michigan; Division of Gastroenterology, Mayo Clinic, Jacksonville, Florida; Biostatistics & Epidemiology, Geisel School of Medicine, Dartmouth University, Hanover, New Hampshire; Public Health Sciences Division, Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, Washington; The Stanford Cancer Institute and Stanford School of Medicine, Department of Medicine, Stanford, California; Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Brisbane, Queensland; and Melbourne School of Population Health, The University of Melbourne, Parkville, Victoria, Australia.
Cancer Epidemiol Biomarkers Prev. 2013 Nov;22(11):2047-54. doi: 10.1158/1055-9965.EPI-13-0409. Epub 2013 Sep 9.
Both shorter and longer telomeres in peripheral blood leukocyte (PBL) DNA have been associated with cancer risk. However, associations remain inconsistent across studies of the same cancer type. This study compares DNA preparation methods to determine telomere length from patients with colorectal cancer.
We examined PBL relative telomere length (RTL) measured by quantitative PCR (qPCR) in 1,033 patients with colorectal cancer and 2,952 healthy controls. DNA was extracted with phenol/chloroform, PureGene, or QIAamp.
We observed differences in RTL depending on DNA extraction method (P < 0.001). Phenol/chloroform-extracted DNA had a mean RTL (T/S ratio) of 0.78 (range 0.01-6.54) compared with PureGene-extracted DNA (mean RTL of 0.75; range 0.00-12.33). DNA extracted by QIAamp yielded a mean RTL of 0.38 (range 0.02-3.69). We subsequently compared RTL measured by qPCR from an independent set of 20 colorectal cancer cases and 24 normal controls in PBL DNA extracted by each of the three extraction methods. The range of RTL measured by qPCR from QIAamp-extracted DNA (0.17-0.58) was less than from either PureGene or phenol/chloroform (ranges, 0.04-2.67 and 0.32-2.81, respectively).
RTL measured by qPCR from QIAamp-extracted DNA was less than from either PureGene or phenol/chloroform (P < 0.001).
Differences in DNA extraction method may contribute to the discrepancies between studies seeking to find an association between the risk of cancer or other diseases and RTL.
外周血白细胞（PBL）DNA 中较短和较长的端粒都与癌症风险相关。然而，在同一癌症类型的研究中，关联仍然不一致。本研究比较了不同的 DNA 制备方法，以确定结直肠癌患者的端粒长度。
我们通过定量 PCR（qPCR）检测了 1033 例结直肠癌患者和 2952 例健康对照者的 PBL 相对端粒长度（RTL）。DNA 分别用酚/氯仿、PureGene 或 QIAamp 提取。
我们观察到 RTL 因 DNA 提取方法而异（P<0.001）。酚/氯仿提取的 DNA 的平均 RTL（T/S 比）为 0.78（范围 0.01-6.54），而 PureGene 提取的 DNA 为 0.75（范围 0.00-12.33）。QIAamp 提取的 DNA 的平均 RTL 为 0.38（范围 0.02-3.69）。随后，我们比较了三种提取方法提取的 PBL DNA 中 20 例结直肠癌病例和 24 例正常对照者的 qPCR 测量的 RTL。QIAamp 提取的 DNA 测量的 RTL 范围（0.17-0.58）小于 PureGene 或酚/氯仿提取的 DNA（范围分别为 0.04-2.67 和 0.32-2.81）。
QIAamp 提取的 DNA 中 qPCR 测量的 RTL 小于 PureGene 或酚/氯仿提取的 DNA（P<0.001）。
DNA 提取方法的差异可能导致寻求癌症或其他疾病风险与 RTL 之间关联的研究结果不一致。
