Cancer-related deaths are primarily driven by the metastatic spread of tumor cells from the primary lesion to distant sites through the bloodstream. Investigating the mechanisms of blood-borne tumor cell dissemination, particularly through the detection and molecular characterization of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) in the patient's blood, has opened new frontiers in cancer research. Recent technological advancements have enabled a detailed analysis of CTCs at genomic, transcriptomic and proteomic levels, along with initial functional studies utilizing patient-derived CTC cell lines. Similarly, the analysis of ctDNA has emerged as a powerful, noninvasive approach to capture the tumor's genomic landscape, monitor disease evolution and detect minimal residual disease. To gain a comprehensive understanding of blood-borne cancer progression in the context of immunotherapies, it is essential to adopt a broader definition of liquid biopsy. This encompasses tumor-derived circulating biomarkers, such as CTCs and cell-free DNA fragments, as well as tumor-induced circulating components of the immune system, including immune cells, cytokines and interleukins, tailored to each patient.

In this webinar, Prof. Dr. Catherine Alix-Panabières will discuss how research on CTCs and ctDNA has provided critical insights into the biology of cancer metastasis and the therapeutic responses of metastatic cells. Current technologies available to detect circulating biomarkers – namely, CTCs and ctDNA – and how these tools have revolutionized our ability to study cancer progression in real time will be discussed. An overview of the biology of these two main circulating biomarkers will also be provided. The pivotal role of CTCs and ctDNA research in uncovering mechanisms of cancer metastasis, with a focus on tumor immune escape strategies, will also be examined, together with how these findings can inform the development of novel approaches to improve clinical outcomes for patients with cancer.