Circulating Tumor DNA Is a Variant of Liquid Biopsy with Predictive and Prognostic Clinical Value in Breast Cancer Patients

Abstract

This paper introduces the reader to the field of liquid biopsies and cell-free nucleic acids, focusing on circulating tumor DNA (ctDNA) in breast cancer (BC). BC is the most common type of cancer in women, and progress with regard to treatment has been made in recent years. Despite this, there remain a number of unresolved issues in the treatment of BC; in particular, early detection and diagnosis, reliable markers of response to treatment and for the prediction of recurrence and metastasis, especially for unfavorable subtypes, are needed. It is also important to identify biomarkers for the assessment of drug resistance and for disease monitoring. Our work is devoted to ctDNA, which may be such a marker. Here, we describe its main characteristics and potential applications in clinical oncology. This review considers the results of studies devoted to the analysis of the prognostic and predictive roles of various methods for the determination of ctDNA in BC patients. Currently known epigenetic changes in ctDNA with clinical significance are reviewed. The possibility of using ctDNA as a predictive and prognostic marker for monitoring BC and predicting the recurrence and metastasis of cancer is also discussed, which may become an important part of a precision approach to the treatment of BC.

LncRNA BCYRN1 as a Potential Therapeutic Target and Diagnostic Marker in Serum Exosomes in Bladder Cancer

“…In recent years, liquid biopsies have been actively studied and clinically applied because of improvements in the technologies for analyzing trace specimen samples. After collecting specimens, cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), circulating tumor cells, proteins, and exosomes, which are all contained in liquid samples, are analyzed to determine the conditions of cells at primary and metastatic sites [ 59 , 60 , 61 , 62 , 63 ]. Exosomes are secreted from living cells, whereas ctDNAs/cfDNAs are derived from necrotic or apoptotic cells [ 64 ].…”

Letter to the editor: Survival benefit of liver resection following complete response to transarterial chemoembolization for intermediate-stage hepatocellular carcinoma: a retrospective, multicenter, cohort study

“…ctDNA released from tumor cells has been widely applied in cancer diagnosis, treatment guidance, prognosis prediction, and tumor recurrence 4 . Besides the quantity of ctNDAs, molecular alterations, including single-nucleotide variations (SNVs), copy number variations (CNVs), DNA methylation aberrations, preferred end motifs or coordinates, and HBV (hepatitis B virus) integration of ctDNA from HCC are associated with tumor initiation, progression, and metastasis, and therefore could truly reflect the tumor response to treatment 5 .…”