Fig. 7
From: Altered cfDNA fragmentation profile in hypomethylated regions as diagnostic markers in breast cancer
Illustration of the potential relationship between cfDNA methylation and fragment size. Nucleosomes with wrapped DNA (yellow line) exist as compact and rigid structure under normal physiological conditions, cfDNA is released through nuclease digestion (scissors) of the linker sequences (black line) and thus produce long cfDNA fragments. During cancer development, chromatin remodeling and DNA demethylation lead to global hypomethylation, and the decreased DNA methylation level result open and accessible wrapped DNA in nucleosomes, therefore, nuclease digestion during apoptosis produce short cfDNA fragments