Circulating biomarkers for diagnosis and response to therapies in cancer patients.

Cancer presents a significant challenge to global health, driving worldwide concerted efforts to advance early detection, predict therapeutic response, and identify novel targeted therapies. Liquid biopsies emerge as promising avenues for discerning cancer biomarkers, offering less invasive approaches compared to conventional methods. Utilizing increasingly robust technologies, diverse bodily fluids can unveil genetic variants, epigenetic modifications, transcriptional alterations, and metabolomic signatures associated with cancer, thereby furnishing valuable insights for clinical management. This chapter intends to review the sources of cancer-related biomarkers found in circulation, prevalent techniques utilized for their identification, and the potential implications of different biomarker types on the management of cancer. Certain biomarkers currently used in clinical practice will be addressed, as well as potential biomarkers still in the study phase, and the inherent challenges in their practical implementation.