Liquid biopsies: genotyping circulating tumor DNA.
Genotyping tumor tissue in search of somatic genetic alterations for actionable information has become routine practice in clinical oncology. Although these sequence alterations are highly informative, sampling tumor tissue has significant inherent limitations; tumor tissue is a single snapshot in time, is subject to selection bias resulting from tumor heterogeneity, and can be difficult to obtain. Cell-free fragments of DNA are shed into the bloodstream by cells undergoing apoptosis or necrosis, and the load of circulating cell-free DNA (cfDNA) correlates with tumor staging and prognosis. Moreover, recent advances in the sensitivity and accuracy of DNA analysis have allowed for genotyping of cfDNA for somatic genomic alterations found in tumors. The ability to detect and quantify tumor mutations has proven effective in tracking tumor dynamics in real time as well as serving as a liquid biopsy that can be used for a variety of clinical and investigational applications not previously possible.
Luis A. Diaz Jr, Swim Across America Laboratory and Ludwig Center for Cancer Genetics and Therapeutics, Johns Hopkins University School of Medicine, Baltimore, MD; and Alberto Bardelli, Institute for Cancer Research and Treatment at Candiolo, University of Torino, Candiolo, and the Fondazione Italiana per la Ricerca sul Cancro Institute of Molecular Oncology, Milan, Italy.
Luis A
LA
Diaz
Alberto
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Bardelli
D001706:Biopsy; D004273:DNA, Neoplasm / Q000097:blood* / Q000235:genetics*; D005838:Genotype; D006801:Humans; D009369:Neoplasms / Q000097:blood* / Q000235:genetics*
D004273:DNA, Neoplasm