Fig 1. Scheme of the animal experiment and library preparation.

LLC cells (10⁶ cells, 0.1 ml) were transplanted intramuscularly (i.m.) into C57Bl/6J mice (male). Starting from day 4 after the tumour transplantation, the animals received i.m. saline buffer or DNase I (0.12 mg/kg) for 10 days. At day 15, 1 h after the last injection, blood sampling was performed, then animals were euthanized and the lungs were taken. ExDNA was isolated from blood serum, and DNA libraries were prepared for subsequent sequencing.