Blood-based RAS mutation testing: concordance with tissue-based RAS testing and mutational changes on progression

Area of Science:

• Oncology
• Molecular Diagnostics
• Genetics

Background:

• Metastatic colorectal cancer (mCRC) treatment decisions often rely on RAS mutation status.
• Tissue biopsy for RAS testing can be invasive and may not always be feasible.
• Non-invasive blood-based testing offers a potential alternative for RAS mutation analysis.

Purpose of the Study:

• To assess the concordance between plasma-based and tissue-based RAS mutation testing in mCRC patients.
• To evaluate the utility of blood-based RAS testing as a surrogate for tissue analysis.
• To investigate changes in RAS mutation status during treatment progression.

Main Methods:

• RAS mutation analysis was performed on plasma samples using the OncoBEAM™ RAS CEIVD kit.
• Plasma results were compared with those from formalin-fixed paraffin-embedded tumor tissue samples.
• Testing was conducted on patients initiating first-line therapy for mCRC.

Main Results:

• An overall concordance of 86.0% (86/100) was observed between plasma and tissue RAS mutation status.
• The assay demonstrated 100% reproducibility across three independent laboratories.
• Approximately 20% of patients exhibited a change in their RAS mutational status upon disease progression.

Conclusions:

• Plasma-based RAS mutation testing shows high concordance with tissue-based testing in mCRC patients.
• Blood-based testing is a reliable alternative to tissue biopsy for RAS mutation assessment.
• Longitudinal plasma testing during treatment may be valuable for guiding mCRC management decisions.