Multiplex detection of KRAS mutations by a matrix-assisted laser desorption/ionization-time of flight mass...

Area of Science:

• Oncology
• Molecular Diagnostics
• Genetics

Background:

• Kirsten rat sarcoma viral oncogene (KRAS) mutations are key drivers in various cancers, influencing treatment response.
• Patients with KRAS-mutated tumors often show resistance to epidermal growth factor receptor (EGFR) inhibitors and do not benefit from chemotherapy.
• Accurate KRAS mutation testing is vital for personalized cancer therapy, but direct sequencing has limitations in clinical sensitivity.

Purpose of the Study:

• To develop and evaluate Restriction Fragment Mass Polymorphism (RFMP) assays for detecting KRAS mutations.
• To assess the sensitivity and applicability of RFMP assays in clinical settings, particularly for formalin-fixed paraffin-embedded (FFPE) samples.

Main Methods:

• Development of RFMP assays targeting KRAS codons 12, 13, and 61.
• Analysis of KRAS mutations in eight KRAS mutant cell lines and 34 FFPE lung cancer tissues using RFMP.
• Comparison of RFMP assay sensitivity against direct sequencing using serial dilutions of mutant KRAS DNA.

Main Results:

• RFMP assays demonstrated good concordance with direct sequencing for KRAS mutation detection.
• RFMP exhibited significantly higher analytical sensitivity (3% mutant alleles) compared to direct sequencing (~25%).
• RFMP successfully identified KRAS mutations in codons 12, 13, and 61 in FFPE lung cancer samples.

Conclusions:

• RFMP assays show potential for efficient clinical application in detecting KRAS mutations.
• The high sensitivity of RFMP is particularly advantageous for analyzing tumor samples with low mutation burdens or high proportions of non-neoplastic cells.