Abstract 381P
Background
Lung cancer remains a leading cause of cancer-related mortality globally, with approximately 2.2 million new cases diagnosed annually. Advances in molecular oncology have revealed actionable mutations (e.g., EGFR) and led to targeted therapies that significantly improve outcomes in selected patient populations. Limitations of routine tissue biopsies, such as procedural risks, have driven the emergence of liquid biopsy as a minimally invasive option for real-time genetic analysis and treatment monitoring in lung cancer. Building on these advancements, we developed Dried Blood Spot–based Tumor mutation Analysis via Recurring Genetic Enrichment Technologies (DBS-TARGET), a novel method that enables patients to collect blood drops via finger prick onto filter paper for ambient-temperature shipment and subsequently high-sensitivity analysis.
Methods
A total of 151 patients with lung cancer were enrolled. The DBS-TARGET assay proceeded as follows: total DNA from dried blood spots on QIAcard FTA Classic cards was isolated with the TIANamp Micro DNA Kit. Purified DNA was adapter-ligated, PCR-amplified, and examined by qPCR using mutation-specific primers and a blocking oligo to suppress wild-type alleles. Cell-free DNA from plasma was purified to generate NGS libraries, which were then either sequenced or used for digital droplet PCR (ddPCR). Results from DBS-TARGET, NGS, and ddPCR were compared accordingly.
Results
Blocking-oligo-assisted qPCR detected genetic mutations at an allelic frequency of 0.01%. Compared with NGS, the TARGET assay for drug-target mutations (n=145) from 102 patients using library DNA demonstrated robust diagnostic performance (AUC=0.94). In parallel testing of 68 DBS samples from 49 patients by both NGS and DBS-TARGET, results were highly comparable (AUC=0.91). Among 9 discrepant mutations, ddPCR analysis yielded an adjusted positive and negative percent agreement of 99% and 92%, respectively, for DBSTARGET.
Conclusions
DBS-TARGET is a patient-friendly and highly sensitive assay capable of identifying genetic mutations with low allele frequencies. This minimally invasive method enhances access to precision oncology for cancer patients, particularly in diverse and resource-limited settings.
Legal entity responsible for the study
H. Gu.
Funding
Hangzhou ShengTing Biotech Co. Ltd, Hangzhou, Zhejiang Province 310018, China
Disclosure
All authors have declared no conflicts of interest.