Circulating tumour cells, commonly known as CTCs, are live tumour cells released by the active tumour into blood circulation, which allows them to travel through the body and potentially form new tumour in other organs, or metastases. The enumeration of CTCs holds prognostic information but, most importantly, CTCs can serve to evaluate the presence of druggable targets, enabling the oncologist to continuously monitor the patients non-invasively and adjust their treatment in a personalised manner. The study of CTCs is also crucial to better understand their role in the metastatic cascade.
