Circulating cell-free tumor DNA analysis in pediatric cancers.

ABSTRACT

Analysis of circulating cell-free tumor DNA (ctDNA) has shown promising results within several clinical applications, including cancer detection, mutation profiling, treatment monitoring and early detection of relapse. Here, we discuss the potential and limitations of ctDNA analysis in pediatric cancer detection, therapy decision making and research. Biological properties associated to ctDNA are highlighted and related to technical constraints in downstream analyses. The effects of ctDNA release and clearance dynamics are illustrated and we argue that reporting ctDNA as a fraction of mutated compared to normal wild-type DNA may be problematic from a biological point of view. We have summarized experimental details, data and conclusions from 50 pediatric ctDNA studies. We discuss the genomic landscape of several pediatric entities and how their specific mutation profiles affects ctDNA analysis, often requiring custom-made technical solutions. Finally, we outline future aspects of ctDNA analysis and what is needed to fully implement it into clinical routine in pediatric oncology.