Computational Systems Biology Methods and Protocols.7z

Chapter 4

The Introduction and Clinical Application of Cell-Free

Tumor DNA

Jun Li, Renzhong Liu, Cuihong Huang, Shifu Chen, and Mingyan Xu

Abstract

Cell-free tumor DNA (ctDNA) is a kind of potential tumor biomarkers originated from cancer lesion in the
circulating liquids. Liquid biopsy, as a minimally invasive or noninvasive manner, is a cutting-edge technol-
ogy to detect ctDNA and other circulating biomarkers in the blood or other body fluids. ctDNA is mostly
used for cancer patients to select targeted drugs in clinical application. In addition, ctDNA could also be
applied to monitor tumor progression and recurrence. In conclusion, ctDNA is a very promising tumor
biomarker for diagnosis and monitoring, which would increasingly become a routine clinical application in
recent years.

KeywordsctDNA, Tumor biomarker, Liquid biopsy, Targeted drug, EGFR, TKI

1 Introduction

Liquid biopsy is a kind of cutting-edge technology to analyze a

range of tumor material in the blood or other body fluids in a

minimally invasive or noninvasive manner. The tumor material

includes circulating tumor cells (CTCs), cell-free tumor DNA

(ctDNA), messenger RNA (mRNA), microRNA (miRNA), and

exosomes. Of these tumor biomarkers, ctDNA are most widely

recognized in clinical application.

In this chapter, we will focus on the introduction and clinical

application of ctDNA. Comparing to ctDNA, cell-free DNA

(cfDNA) is a broader term which describes DNA that is freely

circulating, but is not necessarily of tumor origin. However,

ctDNA is a term much better known in the cancer field and it has

been adopted by clinical experts. So in this chapter, we will use both

cfDNA and ctDNA. When we mention ctDNA, be noted that it

refers to the cfDNA from tumor patients. In next section, we will

also briefly introduce circulating tumor cells (CTCs), circulating

exosomes and circulating mRNA as they are the other major

Tao Huang (ed.),Computational Systems Biology: Methods and Protocols, Methods in Molecular Biology, vol. 1754,
https://doi.org/10.1007/978-1-4939-7717-8_4,©Springer Science+Business Media, LLC, part of Springer Nature 2018

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