Abstract: In an aspect, there is provided a method of detecting the presence of ctDNA from cancer cells in a subject comprising: (a) providing a sample of cell-free DNA from a subject; (b) subjecting the sample to library preparation to permit subsequent sequencing of the cell-free methylated DNA; (c) optionally adding a first amount of filler DNA to the sample, wherein at least a portion of the filler DNA is methylated, then further optionally denaturing the sample; (d) capturing cell-free methylated DNA using a binder selective for methylated polynucleotides; (e) sequencing the captured cell-free methylated DNA; (f) comparing the sequences of the captured cell-free methylated DNA to control cell-free methylated DNAs sequences from healthy and cancerous individuals; (g) identifying the presence of DNA from cancer cells if there is a statistically significant similarity between one or more sequences of the captured cell-free methylated DNA and cell-free methylated DNAs sequences from cancerous individuals; wherein in a

Abstract: There is described herein a method of detecting the presence of DNA from cancer cells in a subject comprising: providing a sample of cell-free DNA from a subject; subjecting the sample to library preparation to permit subsequent sequencing of the cell-free methylated DNA; optionally denaturing the sample; capturing cell-free methylated DNA using a binder selective for methylated polynucleotides; sequencing the captured cell-free methylated DNA; comparing the sequences of the captured cell-free methylated DNA to control cell-free methylated DNAs sequences from healthy and cancerous individuals; identifying the presence of DNA from cancer cells if there is a statistically significant similarity between one or more sequences of the captured cell-free methylated DNA and cell-free methylated DNAs sequences from cancerous individuals.