METHOD

Modified multiplex real-time PCR for quantification of differently sized cell-free DNA fragments

Sokolova EA1,2, Khlistun IV1, Kushlinsky DN3
About authors

1 Biocode Ltd., Moscow, Russia

2 Laboratory of Paleogenomics, Faculty of Natural Sciences,
Novosibirsk State University, Novosibirsk, Russia

3 Blokhin National Medical Research Center of Oncology, Moscow

Correspondence should be addressed: Ekaterina Sokolova
Novomereschensky proezd, d. 9, str. 1, Moscow, Russia, 119619; ur.xednay@8062aeavolokos

About paper

Contribution of the authors to this work: Sokolova EA — research planning, data analysis, drafting of a manuscript; Khlistun IV — experimental work, drafting of a manuscript; Kushlinsky DN — biomaterial sampling, clinical characterization of patients, drafting of a manuscript.

Received: 2017-08-25 Accepted: 2017-08-30 Published online: 2017-10-29
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Fig. 1. Alignment of consensus nucleotide sequences of different Alu families. Underlined are positions of the oligonucleotide primers and the fluorescent probe. Positions in which a nucleotide sequence matches a consensus sequence are shown in dark grey (the bottom line); positions in which nucleotide sequences contain substitutions are shown in light grey. Nucleotide deletions are represented by dashes
Fig. 2. Multiplex PCR for Alu and hLINE-1 amplification. The X-axis represents PCR cycles, the Y-axis shows fluorescence intensity expressed in RFU. Blue curves represent the FAM probe, green curves represent the HEX probe
Fig. 3. The dynamic range of the method. The X-axis shows the sample amount expressed in rel. un., the Y-axis depicts quantification cycle Cq. Measurements were taken in triplicate
Fig. 4. The ratio R of long cfDNA fragments to short ones isolated from the blood plasma of women with ovarian cancer (A) and healthy women (B)
Table 1. Primers and fluorescent probes for Alu and hLINE-1
Table 2. Results of the statistical analysis demonstrate the ratio R of long cfDNA fragments to short ones isolated from the blood plasma of women with ovarian cancer and healthy women