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Published on: March 14, 2019
Direct plasmonic detection of circulating RAS mutated DNA in colorectal cancer patients
Roberta D'Agata1, Noemi Bellassai2, Matteo Allegretti3
1Department of Chemical Sciences, University of Catania, Viale Andrea Doria, 6, 95125, Catania, Italy; INBB, Istituto Nazionale di Biostrutture e Biosistemi, Viale Delle Medaglie D'Oro, 305, 00136, Roma, Italy.
Abstract:
RAS mutations in the blood of colorectal cancer (CRC) patients are emerging as biomarkers of acquired resistance to Epidermal Growth Factor Receptor therapy. Unfortunately, reliable assays granting fast, real-time monitoring of treatment response, capable of refining retrospective, tissue-based analysis, are still needed. Recently, several methods for detecting blood RAS mutations have been proposed, generally relying on multi-step and PCR-based, time-consuming and cost-ineffective procedures. By exploiting a liquid biopsy approach, we developed an ultrasensitive nanoparticle-enhanced plasmonic method for detecting ~1 aM RAS single nucleotide variants (SNVs) in the plasma of CRC patients. The assay does not require the extraction of tumor DNA from plasma and detects it in volumes as low as 40 μL of plasma, which is at least an order of magnitude smaller than that required by state of the art liquid biopsy technologies. The most prevalent RAS mutations are detected in DNA from tumor tissue with 100% sensitivity and 83.33% specificity. Spike-in experiments in human plasma further encouraged assay application on clinical specimens. The assay was proven in plasma from CRC patients and healthy donors, and full discrimination between mutated DNA from patients over wild-type DNA from healthy volunteers was obtained thus demonstrating its promising avenue for cancer monitoring based on liquid biopsy.
Insights
A novel nanoparticle-enhanced plasmonic assay detects RAS mutations in colorectal cancer (CRC) patient plasma. This ultrasensitive liquid biopsy method offers rapid, real-time monitoring of treatment response, improving upon existing diagnostics.
Area of Science:
- Oncology
- Biotechnology
- Molecular Diagnostics
Background:
- RAS mutations in colorectal cancer (CRC) plasma indicate resistance to Epidermal Growth Factor Receptor (EGFR) therapy.
- Current methods for detecting these mutations are often multi-step, PCR-based, time-consuming, and costly.
- There is a need for rapid, real-time assays for monitoring treatment response in CRC patients.
Purpose of the Study:
- To develop an ultrasensitive, nanoparticle-enhanced plasmonic assay for detecting RAS single nucleotide variants (SNVs) in CRC patient plasma.
- To establish a rapid, cost-effective liquid biopsy method for real-time monitoring of colorectal cancer treatment response.
Main Methods:
- Development of a nanoparticle-enhanced plasmonic assay for ultrasensitive detection of RAS SNVs.
- Utilized a liquid biopsy approach requiring minimal plasma volume (40 μL).
- Assessed assay performance using spike-in experiments and clinical specimens from CRC patients and healthy donors.
Main Results:
- The assay detected RAS SNVs at attomolar concentrations (~1 aM) in CRC patient plasma.
- Achieved 100% sensitivity and 83.33% specificity for detecting prevalent RAS mutations compared to tissue analysis.
- Demonstrated full discrimination between mutated DNA in CRC patients and wild-type DNA in healthy volunteers.
Conclusions:
- The developed ultrasensitive plasmonic assay provides a promising tool for rapid, real-time monitoring of colorectal cancer treatment response via liquid biopsy.
- This method overcomes limitations of existing assays, offering improved speed, sensitivity, and reduced sample volume requirements.
- The assay holds potential for refining cancer monitoring and personalized treatment strategies in colorectal cancer.
