Extended Enrichment for Ultrasensitive Detection of Low-Frequency Mutations by Long Blocker Displacement...

Area of Science:

• Molecular Biology
• Genetics
• Oncology

Background:

• Detecting low-frequency DNA mutation hotspots is crucial for cancer diagnosis but faces sensitivity and throughput limitations with current methods like quantitative PCR (qPCR) and allele-specific PCR.
• Existing techniques struggle to accurately identify rare mutations, hindering early and precise cancer detection.

Purpose of the Study:

• To develop an ultrasensitive and multiplexed method for detecting low-frequency DNA mutation hotspots.
• To improve upon the limitations of current diagnostic tools for cancer-related genetic variations.

Main Methods:

• Development of long blocker displacement amplification (LBDA) coupled with qPCR.
• Utilizing long blocker oligos designed to specifically target wildtype sequences, enabling enrichment of mutant sequences.
• Application of the LBDA-qPCR assay to detect KRAS and NRAS mutation hotspots in synthetic and colorectal cancer samples.

Main Results:

• LBDA-qPCR achieved ultrasensitive detection of mutations down to 0.5% variant allele frequency (VAF).
• The method demonstrated a median enrichment factor of 1,000-fold for mutant DNA compared to wildtype.
• A single-plex assay successfully covered 81 mutations in KRAS and NRAS hotspots, with results validated by Sanger and next-generation sequencing.

Conclusions:

• LBDA-qPCR offers a simple, ultrasensitive, and multiplexed approach for detecting low VAF mutation hotspots.
• This technique presents a powerful new tool for enhancing cancer diagnosis and monitoring strategies.