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Analysis of KRAS mutations in circulating tumor DNA and colorectal cancer tissue
Yankui Liu1, Longhai Li2, Yu Tian2
1Department of Pathology, The Affiliated Hospital of Jiangnan University, Wuxi, China.
Abstract:
The mutation status of KRAS is important for anti-EGFR therapy in colorectal cancer (CRC) patients; however, detection of KRAS mutations in circulating tumor DNA (ctDNA) is problematic. We investigated tissue and plasma assays for KRAS mutations in CRC patients. The KRAS status of 407 CRC patients was evaluated using integration of amplification refractory mutation system polymerase chain reaction (PCR), melting curves and wild type DNA blocking (IAMB) in tissue and plasma samples. Disparate cases were re-evaluated by Sanger sequencing of tissue samples. General characteristics and tumor biomarkers including CEA, CA19-9 and CA125 were characterized. The prevalence of KRAS mutations was 40.8% in plasma and 49.1% in tissue. The overall percent agreement, positive percent agreement and negative percent agreement were 82.3, 76.3 and 90.8%, respectively. Older patients and higher TNM stage exhibited increased sensitivity for detecting KRAS mutations in plasma. We found 54.1% of patients with KRAS mutations using parallel analysis of tissue and plasma; only 36.4% of patients were detected by series analysis. We found that plasma based KRAS detection with IAMB technology is an alternative to tissue based KRAS testing. KRAS mutations can be identified more easily when both assays are used together.
Insights
Detecting KRAS mutations in colorectal cancer (CRC) patients is crucial for anti-EGFR therapy. Plasma-based KRAS testing using IAMB technology offers a viable alternative to tissue analysis, especially when combined.
Area of Science:
- Oncology
- Molecular Diagnostics
- Genetics
Background:
- KRAS mutation status is critical for guiding anti-EGFR therapy in colorectal cancer (CRC).
- Detecting KRAS mutations in circulating tumor DNA (ctDNA) presents challenges.
- Accurate KRAS mutation detection is essential for personalized CRC treatment strategies.
Purpose of the Study:
- To investigate and compare the efficacy of tissue and plasma assays for KRAS mutation detection in CRC patients.
- To evaluate the performance of the Integration of Amplification Refractory Mutation System Polymerase Chain Reaction (PCR), melting curves, and wild type DNA blocking (IAMB) technology.
- To determine the optimal strategy for KRAS mutation detection by analyzing parallel versus series approaches of tissue and plasma testing.
Main Methods:
- Evaluated KRAS status in 407 CRC patients using IAMB technology on both tissue and plasma samples.
- Re-evaluated discordant cases using Sanger sequencing of tissue samples.
- Analyzed general patient characteristics and tumor biomarkers (CEA, CA19-9, CA125).
Main Results:
- Prevalence of KRAS mutations was 40.8% in plasma and 49.1% in tissue.
- Overall agreement between plasma and tissue assays was 82.3%, with 90.8% negative percent agreement.
- Plasma assay sensitivity for KRAS mutations increased with older patient age and higher TNM stage.
- Parallel analysis of tissue and plasma detected KRAS mutations in 54.1% of patients, compared to 36.4% with series analysis.
- Plasma-based KRAS detection using IAMB technology demonstrated high concordance with tissue-based testing.
Conclusions:
- Plasma-based KRAS detection using IAMB technology is a reliable alternative to tissue-based testing for CRC patients.
- Combined analysis of tissue and plasma samples significantly improves the detection rate of KRAS mutations.
- This approach enhances the identification of patients eligible for anti-EGFR therapy, optimizing treatment decisions.
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