Transl Lung Cancer Res. 2026 Apr 30;15(4):105. doi: 10.21037/tlcr-2025-aw-1321. Epub 2026 Mar 20.

ABSTRACT

BACKGROUND AND OBJECTIVE: Lung cancer is the leading cause of cancer-related mortality worldwide, with non-small cell lung cancer (NSCLC) accounting for the majority of cases. Tissue biopsies are invasive and often limited, emphasizing the need for minimally invasive biomarkers. Circulating tumor DNA (ctDNA) obtained through liquid biopsy enables non-invasive tumor profiling. While most applications rely on mutation detection, DNA methylation of ctDNA (Met-ctDNA) represents a promising complementary approach. This review explores technological methods for detecting ctDNA methylation and summarizes its potential clinical applications in NSCLC.

METHODS: We analyzed recent studies describing methylation detection technologies, including polymerase chain reaction (PCR)-based, sequencing, microarray, and enrichment approaches. We also reviewed evidence on diagnostic, prognostic, and predictive applications of Met-ctDNA, as well as its role in monitoring minimal residual disease (MRD).

KEY CONTENT AND FINDINGS: Technically, sodium bisulfite conversion remains the gold standard, but new bisulfite-free and ultrasensitive strategies are emerging. Clinically, gene-specific hypermethylation (e.g., SHOX2, RASSF1A, and APC) provides high diagnostic specificity. Prognostic studies consistently link methylation markers and scores to overall and progression-free survival. Dynamic methylation changes predict response to chemotherapy, immunotherapy, and targeted therapy, especially in patients without actionable mutations. Moreover, Met-ctDNA enables earlier detection of MRD and recurrence than imaging, improving personalized follow-up. However, variability in sample processing, assay performance, and marker specificity remain significant barriers. Confounding factors such as age-related methylation variability, environmentally and lifestyle-induced methylation changes, and clonal hematopoiesis must also be considered when selecting relevant markers and interpreting results.

CONCLUSIONS: Met-ctDNA is a versatile, non-invasive biomarker with diagnostic, prognostic, and predictive value in NSCLC. Standardization of methodologies and validation in large-scale prospective trials are essential to enable its integration into routine clinical practice.

PMID:42170273 | PMC:PMC13186644 | DOI:10.21037/tlcr-2025-aw-1321