OncoFOLLOW is a test based on the analysis of circulating tumor DNA in blood. It is used to monitor the progression of the tumor (burden of the disease) and to detect lack of response or resistance to treatment as soon as it appears. This assay is customised for each patient, as it analyses up to 15 variants previously identified in the tumour of the patient. In addition, it sequences a fixed panel of 40 genes associated with response/resistance to targeted therapies and immunotherapy, and/or frequently mutated in cance