The main objective of the SISTEMA project is to develop non-invasive diagnostic tests for the detection and quantification in blood of markers of Mesenchymal Epithelial Transition, a mechanism that characterises certain types of cancer such as breast and lung cancer. Cancer is still one of the leading causes of death in Western countries. In 2014, there were an estimated 1,665,540 new cancer cases and 585,720 deaths in the United States alone. The World Health Organisation (WHO) and Eurostat predict 1,323,600 deaths in Europe, a figure slightly down on previous statistics but still underlining the existence and seriousness of the problem. It is no coincidence that cancer is one of the main areas of investment in the European Horizon 2020 programme. In recent years, the hypothesis that the process of carcinogenesis is driven by the activation of a particular panel of genes/proteins that enable cancer cells to acquire malignant characteristics has become increasingly popular. This process goes by the name Epithelial Mesenchymal Transition (EMT) and characterises all human epithelial tumours. This process allows epithelial tumour cells to acquire mesenchymal characteristics giving them stem, invasive, and chemoresistant properties.