Crystal digital droplet PCR for detection and quantification of circulating EGFR sensitizing and resistance mutations in advanced non-small cell lung cancer
Cécile Jovelet1, Jordan Madic2, Jordi Remon3
1Plateforme de Génomique-BMO et Centre de Ressources Biologiques, AMMICA, INSERM US23/CNRS UMS3655, Gustave Roussy, Villejuif, France.
Abstract:
Over the past years, targeted therapies using tyrosine kinase inhibitors (TKI) have led to an increase in progression-free survival and response rate for a subgroup of non-small cell lung cancer (NSCLC) patients harbouring specific gene abnormalities compared with chemotherapy. However long-lasting tumor regression is rarely achieved, due to the development of resistant tumoral subclones, which requires alternative therapeutic approaches. Molecular profile at progressive disease is a challenge for making adaptive treatment decisions. The aim of this study was to monitor EGFR-mutant tumors over time based on the quantity of mutant DNA circulating in plasma (ctDNA), comparing two different methods, Crystal™ Digital™ PCR and Massive Parallel Sequencing (MPS). In plasma circulating cell free DNA (cfDNA) of 61 advanced NSCLC patients we found an overall correlation of 78% between mutated allelic fraction measured by Crystal Digital PCR and MPS. 7 additional samples with sensitizing mutations and 4 additional samples with the resistance mutation were detected with Crystal Digital PCR, but not with MPS. Monitoring levels of both mutation types over time showed a correlation between levels and trends of mutated ctDNA detected and clinical assessment of disease for the 6 patients tested. In conclusion, Crystal Digital PCR exhibited good performance for monitoring mutational status in plasma cfDNA, and also appeared as better suited to the detection of known mutations than MPS in terms of features such as time to results.
Insights
Crystal Digital PCR offers superior detection of EGFR mutations in non-small cell lung cancer (NSCLC) circulating tumor DNA (ctDNA) compared to Massive Parallel Sequencing (MPS), aiding adaptive treatment decisions.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Tyrosine kinase inhibitors (TKIs) improve outcomes for some non-small cell lung cancer (NSCLC) patients with specific mutations.
- Tumor resistance to TKIs necessitates alternative therapeutic strategies and adaptive treatment decisions.
- Monitoring molecular profiles of tumors at disease progression is crucial for effective treatment planning.
Purpose of the Study:
- To compare Crystal™ Digital™ PCR and Massive Parallel Sequencing (MPS) for monitoring epidermal growth factor receptor (EGFR)-mutant tumors over time.
- To assess the quantity of circulating tumor DNA (ctDNA) in plasma as a method for tracking tumor evolution.
- To evaluate the utility of ctDNA monitoring in guiding adaptive treatment decisions for advanced NSCLC.
Main Methods:
- Plasma circulating cell-free DNA (cfDNA) from 61 advanced NSCLC patients was analyzed.
- Mutated allelic fraction was measured using both Crystal™ Digital™ PCR and MPS.
- Correlation between the two methods was assessed, and detection rates for sensitizing and resistance mutations were compared.
Main Results:
- An overall correlation of 78% was found between mutated allelic fraction measurements by Crystal™ Digital™ PCR and MPS.
- Crystal™ Digital™ PCR detected 7 additional samples with sensitizing mutations and 4 with resistance mutations missed by MPS.
- Monitoring ctDNA levels over time showed a correlation with clinical assessment of disease in 6 patients.
Conclusions:
- Crystal™ Digital™ PCR demonstrates good performance for monitoring mutational status in plasma cfDNA.
- Crystal™ Digital™ PCR appears better suited than MPS for detecting known mutations, offering faster results.
- Accurate and timely monitoring of ctDNA mutations can support adaptive treatment strategies in NSCLC.
