A liquid biopsy is often described as a sensitive and specific blood test to detect circulating tumor cells (CTCs). CTCs, shed by both the primary and metastasized tumors, carry specific information about their origins and markers that will enable us to discover new diagnosis, prognosis and therapeutic targets. This slidedeck gives an overview of the recent progress in exploring the predictive potential of circulating biomarkers, including circulating tumor cells, circulating tumor DNA, microRNAs, long non-coding RNAs (lncRNAs) and exosomes. Addressing both biological and technical aspects, we detail the isolation and characterization of circulating biomarkers. Challenges and solutions are also featured.