Liquid biopsies are non-invasive sampling methods of the blood or urine. Dying cells shed their DNA in the form of cell-free DNA (cfDNA) into the bloodstream from where it can be filtered into the urine. cfDNA carries genetic and epigenetic signatures of their tissue-of-origin which can be detected and quantified. Current diagnostic applications of cfDNA, such as non-invasive prenatal testing, detection of transplant rejection or of cancer rely on point mutations or somatic copy number alterations. However, the epigenetic signatures are receiving increasing interest, as they can inform on gene expression patterns, or shed light on the location of the disease.
The lecture will present how DNA methylation and nucleosome positioning analysis from liquid biopsies can contribute to the detection and localization of primary or residual disease. It will highlight the advantages and pitfalls of conventional PCR-based and high throughput sequencing-based methods, including short- and long-read sequencing techniques.