Open AccessDroplet digital PCR-based detection of circulating tumor DNA from pediatric high grade and diffuse midline glioma patients
Author(s) -
Elisa Izquierdo,
Paula Proszek,
Giulia Pericoli,
Sara Temelso,
Matthew Clarke,
Diana Carvalho,
Alan Mackay,
Lynley V. Marshall,
Fernando Carceller,
Darren Hargrave,
Birgitta Lannering,
Zdeněk Pavelka,
Simon Bailey,
Natacha EntzWerlé,
Jacques Grill,
Gilles Vassal,
Daniel Rodriguez,
Paul S. Morgan,
Tim Jaspan,
Angela Mastronuzzi,
Maria Vinci,
Michael Hubank,
Chris Jones
Publication year - 2021
Publication title -
neuro-oncology advances
Language(s) - English
Resource type - Journals
ISSN - 2632-2498
DOI - 10.1093/noajnl/vdab013
Subject(s) - liquid biopsy , digital polymerase chain reaction , cerebrospinal fluid , circulating tumor dna , medicine , biopsy , glioma , cell free fetal dna , pathology , oncology , cancer research , polymerase chain reaction , biology , gene , cancer , pregnancy , biochemistry , fetus , genetics , prenatal diagnosis
Background The use of liquid biopsy is of potential high importance for children with high grade (HGG) and diffuse midline gliomas (DMG), particularly where surgical procedures are limited, and invasive biopsy sampling not without risk. To date, however, the evidence that detection of cell-free DNA (cfDNA) or circulating tumor DNA (ctDNA) could provide useful information for these patients has been limited, or contradictory. Methods We optimized droplet digital PCR (ddPCR) assays for the detection of common somatic mutations observed in pediatric HGG/DMG, and applied them to liquid biopsies from plasma, serum, cerebrospinal fluid (CSF), and cystic fluid collected from 32 patients. Results Although detectable in all biomaterial types, ctDNA presented at significantly higher levels in CSF compared to plasma and/or serum. When applied to a cohort of 127 plasma specimens from 41 patients collected from 2011 to 2018 as part of a randomized clinical trial in pediatric non-brainstem HGG/DMG, ctDNA profiling by ddPCR was of limited use due to the small volumes (mean = 0.49 mL) available. In anecdotal cases where sufficient material was available, cfDNA concentration correlated with disease progression in two examples each of poor response in H3F3A _K27M-mutant DMG, and longer survival times in hemispheric BRAF _V600E-mutant cases. Conclusion Tumor-specific DNA alterations are more readily detected in CSF than plasma. Although we demonstrate the potential of the approach to assessing tumor burden, our results highlight the necessity for adequate sample collection and approach to improve detection if plasma samples are to be used.