10-Plex Digital Polymerase Chain Reaction with Four-Color Melting Curve Analysis for Simultaneous KRAS and BRAF...

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• Digital PCR (dPCR) offers sensitive nucleic acid quantification for liquid biopsies but suffers from fluorescence fluctuations, limiting multiplexing.
• Current dPCR methods struggle with amplification variability in small partitions, impacting multiplexing capabilities.

Purpose of the Study:

• To develop a novel measurement method combining dPCR with melting curve analysis for highly multiplexed genotyping.
• To enhance genotyping accuracy in dPCR by utilizing melting temperature (Tm) in addition to fluorescence intensity and dye color.

Main Methods:

• Asymmetric PCR was performed on a dPCR chip with up to 2 × 10^4 wells.
• Molecular beacon probes were used, and fluorescence images were captured during controlled temperature changes to measure melting curves for each well.
• Genotyping was achieved by analyzing fluorescence intensity, probe dye color, and melting temperature (Tm).

Main Results:

• The combined dPCR and melting curve analysis method demonstrated improved genotyping accuracy due to the stability of Tm values.
• Simultaneous identification of wild-type KRAS, BRAF, and eight specific cancer-related gene mutants was achieved using four-color melting curve analysis.
• This study represents the first demonstration of genotyping 10 distinct DNA groups, including single mutations in cancer genes, using this combined approach.

Conclusions:

• Combining dPCR with melting curve analysis offers a robust solution for highly multiplexed genotyping, overcoming dPCR's limitations.
• The use of melting temperature (Tm) significantly enhances genotyping accuracy, making the method suitable for sensitive detection of multiple genetic targets.
• This innovative technique holds promise for advanced applications in liquid biopsies and cancer diagnostics.