FIELD: biotechnology.
SUBSTANCE: biological agent for analysing the level of extracellular tumour DNA in biomaterial samples is described. The agent is a synthetic DNA fragment 88 base pairs long, presented in the form of two complementary DNA chains with the sequences SEQ ID NO: 1 and SEQ ID NO: 2. The agent is used as an exogenous control in the determination of extracellular tumour DNA in biomaterial samples. A kit for performing digital polymerase chain reaction is also described. The kit includes the described biological agent and forward and reverse oligonucleotide primers with the sequences SEQ ID NO: 3 and SEQ ID NO: 4, respectively, as well as an oligonucleotide fluorescently labelled probe with the sequence SEQ ID NO: 5. A method of analysing the level of extracellular tumour DNA in biomaterial samples for liquid biopsy is disclosed. Reagents from the described kit are added to the sample. DNA is isolated from biomaterial. Quantitative determination of extracellular tumour DNA and quantitative determination of the described agent are carried out. The DNA extraction coefficient used to normalize the level of extracellular tumour DNA is calculated.
EFFECT: invention can be used to improve the accuracy and reproducibility of quantitative analysis of the level of tumour DNA in biomaterial samples for liquid biopsy in cancer.
7 cl, 4 dwg, 2 tbl, 2 ex
