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An extraction‐free method for quantifying cell‐free DNA in the serum of cancer patients

Xie, Li, Guo, Wei, Liu, Lisheng, Wei, Ling, Song, Xingguo, Song, Xianrang
Journal of chemical technology and biotechnology 2018 v.93 no.12 pp. 3590-3596
DNA, blood serum, isolation techniques, lung neoplasms, monitoring, patients, people, quantitative polymerase chain reaction
BACKGROUND: Cell‐free DNA (cfDNA) is an important marker for cancer diagnosis and monitoring. Extraction of cfDNA from serum is indispensable for its quantification, and the DNA isolation procedure can significantly influence the quantification and qualification of DNA. RESULTS: A cfDNA‐extraction‐free (EF) method and a SuperGreen quantitative PCR assay for determining total cfDNA in serum were developed. The cfDNA from the EF method did not affect the specificity and sensitivity of quantitative polymerase chain reaction (qPCR) assay. It was found that the median amount of spike‐in cfDNA quantified by different isolation methods varied from 3.01 to 83.81 ng mL⁻¹. The efficiency of DNA extraction by the EF method was significantly better than that in the case of other cfDNA extraction kits. The serum samples from the patients with nonsmall cell lung cancer (NSCLC) contained a higher concentration of cfDNA than that in healthy people, and cfDNA showed a better prognostic ability for diagnosing NSCLC. CONCLUSION: The cfDNA‐EF method gives a more reliable, easy, and low‐cost estimate of total cell‐free DNA quantity in serum. © 2018 Society of Chemical Industry