The concept of liquid biopsy was introduced in the field of cancer diagnostics in 2010. It refers to the probing of easily-accessible body fluids (mainly blood, but also cerebrospinal fluid, urine, sputum, ascites, or other) for circulating tumor-derived cells, extracellular vesicles, or molecules that can convey information about disease status and prognosis, patient stratification, and responses to treatment.
The reliable analysis and interpretation of liquid biopsy relies on the development of highly sensitive detection methods and discovery of tumor-specific markers, and involves several challenges. Current challenges in the field and future directions are discussed by key experts through an article collection. You may refer to these open access articles for more information on: circulating tumor cells,; circulating tumor DNA; liquid biopsy monitoring epigenetic markers; analysis of DNA in extracellular vesicles; challenges in the clinical application of plasma protein biomarkers; and platelets as liquid biopsy sources for cancer detection.
 Alix-Panabiéres C, Pantel K (2021) Liquid biopdy: from discovery to clinical implementation. Mol Oncol. 15, 1617– 1621
 Vasseur A, Kiavue N, Bidard FC, Pierga JY & Cabel L (2020) Clinical utility of circulating tumor cells: an update. Mol Oncol. 15, 1647– 1666
 Labib M & Kelley SO (2021) Circulating tumor cell profiling for precision oncology. Mol Oncol. 15, 1622– 1646
 Filipska M & Rosell R (2020) Mutated circulating tumor DNA as a liquid biopsy in lung cancer detection and treatment. Mol Oncol. 15, 1667– 1682
 Lianidou E (2020) Detection and relevance of epigenetic markers on ctDNA: recent advances and future outlook. Mol Oncol. 15, 1683– 1700
 Elzanowska J, Semira C & Costa-Silva B (2020) DNA in extracellular vesicles: biological and clinical aspects. Mol Oncol. 15, 1701– 1714
 Landegren U & Hammond M (2020) Cancer diagnostics based on plasma protein biomarkers: hard times but great expectations. Mol Oncol. 15, 1715– 1726
 Antunes-Ferreira M, Koppers-Lalic D & Wurdinger T (2020) Circulating platelets as liquid biopsy sources for cancer detection. Mol Oncol. 15, 1727– 1743