# Highly Sensitive and Specific Lateral Flow Detection for DNA Methylation Based on GIaI-Mediated Specific-Terminal-Mediated Polymerase Chain Reaction

## TL;DR

This paper introduces a new method for detecting DNA methylation with high sensitivity and specificity, using a combination of enzyme digestion and PCR, which could help in early cancer diagnosis.

## Contribution

The novel integration of GlaI digestion and STEM-PCR with LFD enables highly sensitive and specific DNA methylation detection.

## Key findings

- The assay detected methylated DNA at 0.1% sensitivity with no cross-reactivity from unmethylated DNA.
- Validation with FFPE tissue samples showed 100% consistency with standard real-time STEM-PCR.
- The method provides a visual readout suitable for point-of-care diagnostics.

## Abstract

Sensitive and specific detection of DNA methylation is crucial for the early diagnosis of various human diseases, particularly cancers. However, conventional methylation detection methods often face challenges in balancing both sensitivity and specificity. In this study, we present a novel approach that integrates the high specificity of methylation-dependent restriction endonuclease (GlaI) digestion with the amplification efficiency of specific terminal-mediated polymerase chain reaction (STEM-PCR). This combination enables selective amplification of methylated DNA, which is then detected through lateral flow detection (LFD), providing a simple, visual readout. As a proof of concept, a STEM-PCR-LFD assay was applied to detect methylated Septin 9, a biomarker for colorectal cancer. The assay demonstrated a sensitivity of approximately 0.1% (10 copies of methylated template per reaction), with no cross-reactivity observed when 10,000 copies of unmethylated DNA were included as background. Furthermore, the assay was validated with ten formalin-fixed paraffin-embedded (FFPE) tissue samples, achieving 100% consistency with standard real-time STEM-PCR. This method offers a highly sensitive, specific, and accessible platform for DNA methylation detection, with potential for early disease diagnosis.