Development of Highly Sensitive Digital Droplet PCR for Detection of cKIT Mutations in Circulating Free DNA That Mediate Resistance to TKI Treatment for Gastrointestinal Stromal Tumor (GIST)

BACKGROUND: Mutations in cKIT or PDGFRA are found in up to 90% of patients with gastrointestinal stromal tumors (GISTs). Previously, we described the design, validation, and clinical performance of a digital droplet (dd)PCR assay panel for the detection of imatinib-sensitive cKIT and PDFGRA mutations in circulating tumor (ct)DNA. In this study, we developed and validated a set of ddPCR assays for the detection of cKIT mutations mediating resistance to cKIT kinase inhibitors in ctDNA. In addition, we cross-validated these assays using next generation sequencing (NGS).

METHODS: We designed and validated five new ddPCR assays to cover the most frequent cKIT mutations mediating imatinib resistance in GISTs. For the most abundant imatinib-resistance-mediating mutations in exon 17, a drop-off, probe-based assay was designed. Dilution series (of decreasing mutant (MUT) allele frequency spiked into wildtype DNA) were conducted to determine the limit of detection (LoD). Empty controls, single wildtype controls, and samples from healthy individuals were tested to assess specificity and limit of blank (LoB). For clinical validation, we measured cKIT mutations in three patients and validated results using NGS.

RESULTS: Technical validation demonstrated good analytical sensitivity, with a LoD ranging between 0.006% and 0.16% and a LoB ranging from 2.5 to 6.7 MUT fragments/mL. When the ddPCR assays were applied to three patients, the abundance of ctDNA in serial plasma samples reflected the individual disease course, detected disease activity, and indicated resistance mutations before imaging indicated progression. Digital droplet PCR showed good correlation to NGS for individual mutations, with a higher sensitivity of detection.

CONCLUSIONS: This set of ddPCR assays, together with our previous set of cKIT and PDGFRA mutations assays, allows for dynamic monitoring of cKIT and PDGFRA mutations during treatment. Together with NGS, the GIST ddPCR panel will complement imaging of GISTs for early response evaluation and early detection of relapse, and thus it might facilitate personalized decision-making.

Medienart:

E-Artikel

Erscheinungsjahr:

2023

Erschienen:

2023

Enthalten in:

Zur Gesamtaufnahme - volume:24

Enthalten in:

International journal of molecular sciences - 24(2023), 6 vom: 12. März

Sprache:

Englisch

Beteiligte Personen:

Rassner, Michael [VerfasserIn]
Waldeck, Silvia [VerfasserIn]
Follo, Marie [VerfasserIn]
Jilg, Stefanie [VerfasserIn]
Philipp, Ulrike [VerfasserIn]
Jolic, Martina [VerfasserIn]
Wehrle, Julius [VerfasserIn]
Jost, Philipp J [VerfasserIn]
Peschel, Christian [VerfasserIn]
Illert, Anna Lena [VerfasserIn]
Duyster, Justus [VerfasserIn]
Scherer, Florian [VerfasserIn]
von Bubnoff, Nikolas [VerfasserIn]

Links:

Volltext

Themen:

8A1O1M485B
9007-49-2
Biomarkers
CKIT
Cell-Free Nucleic Acids
Circulating Tumor DNA
CtDNA
DNA
DdPCR
EC 2.7.10.1
GIST
Imatinib Mesylate
Journal Article
Liquid biopsy
PDGFRA
Proto-Oncogene Proteins c-kit
Receptor Protein-Tyrosine Kinases

Anmerkungen:

Date Completed 31.03.2023

Date Revised 31.03.2023

published: Electronic

Citation Status MEDLINE

doi:

10.3390/ijms24065411

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM354874500