Direct comparison study of DNA methylation markers in EpCAM-positive circulating tumour cells, corresponding circulating tumour DNA, and paired primary tumours in breast cancer.

Circulating Tumour Cells (CTCs) and circulating tumour DNA (ctDNA) represent a non-invasive liquid biopsy approach for the follow-up and therapy management of cancer patients. We evaluated whether DNA methylation status in CTCs and ctDNA is comparable and whether it reflects the status of primary tumours. We compared the methylation status of three genes, SOX17, CST6 and BRMS1 in primary tumours, corresponding CTCs and ctDNA in 153 breast cancer patients and healthy individuals, by using real time methylation specific PCR.