Colorectal cancer (CRC) is one of the most common tumour with approximately 376,000 new cases diagnosed each year in Europe, accounting almost 13% of all cancers.Mortality and survival rates in CRC are highly influenced by the stage of the disease at the moment of diagnosis, with 5-year survival rates dropping from 95% in stage Ⅰ to<5% in stage ⅣV.These data clearly show the need for early diagnosis to surgically treat patients at sub-clinical stage and improve survival.For this reason, during last few years, there has been an increasing interest for molecular biomarkers as non invasive diagnostic tools to identify at-risk population and early cancer detection.Several studies have already reported the presence of CFDNA in cancer patients plasma, showing the same characteristics ofprimary tumour DNA such as oncogene expressions, tumour-suppressor gene mutations, microsatellite and epigenetic alterations.