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World J Gastrointest Oncol. Dec 15, 2016; 8(12): 810-818
Published online Dec 15, 2016. doi: 10.4251/wjgo.v8.i12.810
Role of circulating free DNA in colorectal cancer
Alexios Matikas, Alexandra Voutsina, Maria Trypaki, Vassilis Georgoulias
Alexios Matikas, Alexandra Voutsina, Maria Trypaki, Vassilis Georgoulias, Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Voutes, Heraklion, 71110 Crete, Greece
Author contributions: Matikas A conceptualized and designed the review together with Georgoulias V; Matikas A, Voutsina A and Trypaki M drafted the initial manuscript; all authors reviewed and approved the final manuscript as submitted.
Conflict-of-interest statement: The authors declare no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Alexios Matikas, MD, Msc, Laboratory of Tumor Cell Biology, School of Medicine, University of Crete, Voutes, PO Box 1352, Heraklion, 71110 Crete, Greece. georgsec@med.uoc.gr
Telephone: +30-2810-392783 Fax: +30-2810-543601
Received: June 17, 2016
Peer-review started: June 18, 2016
First decision: July 27, 2016
Revised: September 6, 2016
Accepted: October 5, 2016
Article in press: October 9, 2016
Published online: December 15, 2016
Processing time: 172 Days and 14.2 Hours
Abstract

The gradual elucidation of the underlying biology of colorectal cancer has provided new insights and therapeutic options for patients with metastatic disease which are selected according to predictive biomarkers. This precision medicine paradigm, however, is incomplete since not all eligible patients respond to these agents and prognostic stratification is largely based on clinicopathologic variants. Importantly, no robust data exist to help properly select patients with localized disease at high risk for recurrence and most likely to benefit from adjuvant chemotherapy. There is a rapidly expanding body of literature regarding the role of the qualitative and quantitative analysis of circulating free DNA in various neoplasms, which consistently outperforms traditional tumor markers both as a predictive and as a prognostic marker. Several lines of evidence suggest that circulating free DNA may exhibit a complementary role to existing modalities for the early diagnosis of colorectal cancer, the selection of patients for adjuvant chemotherapy, for the follow-up of treated patients, for the selection of treatment for advanced disease and the assessment of response and for determining the prognosis of patients. These data, which are reviewed here, illustrate the important role that circulating biomarkers may soon have at the daily clinical practice.

Keywords: Cell-free DNA; Circulating tumor DNA; Colorectal cancer; Biomarker; KRAS

Core tip: Published studies clearly indicate that cell-free DNA levels and the detection of specific molecular events in the plasma of colorectal cancer patients is a relevant prognostic and predictive biomarker, with clinically meaningful value at various disease settings such as asymptomatic screening, follow-up after curative surgery and metastatic disease. Further randomized studies are needed before these techniques are implemented at the daily practice.