Liquid biopsy — the analysis of cancer-derived nucleic acids, proteins, or cells circulating in peripheral blood — has moved from research promise to clinical reality across multiple oncology applications. Circulating tumor DNA (ctDNA) analysis is now an FDA-cleared companion diagnostic for lung cancer (Guardant360 CDx, Foundation Medicine FoundationOne Liquid CDx), colorectal cancer, and other tumor types — enabling molecular profiling from blood when tissue biopsy is not feasible and providing real-time monitoring of treatment response. More transformative applications — cancer early detection through multi-cancer early detection (MCED) tests — are in advanced clinical validation stages with potential to fundamentally change population cancer screening. Our laboratory supplies section supports clinical laboratories providing genomic and liquid biopsy testing.
ctDNA as a Companion Diagnostic
Tumor tissue molecular profiling (NGS panels) identifies actionable mutations guiding targeted therapy selection — the foundation of precision oncology. Liquid biopsy ctDNA profiling complements tissue biopsy by: (1) capturing tumor heterogeneity (ctDNA reflects mutations from all tumor lesions rather than a single biopsy site); (2) enabling profiling when tissue is unavailable or biopsy is high-risk; (3) detecting acquired resistance mutations as they emerge (real-time treatment monitoring); (4) providing an earlier response signal than imaging (ctDNA clearance precedes radiographic response by 6–8 weeks). In NSCLC, FDA-cleared ctDNA assays enable EGFR, ALK, KRAS, and other actionable mutation detection from plasma — the NILE trial demonstrated ctDNA concordance with tissue testing in 98.5% of patients with detectable ctDNA. FoundationOne Liquid CDx and Guardant360 CDx are the leading clinical platforms.
Multi-Cancer Early Detection (MCED): The Promise of Grail Galleri
Grail's Galleri MCED test — analyzing cell-free DNA methylation patterns to identify cancer-associated DNA and predict tissue of origin — received FDA Breakthrough Device designation and is available through physician prescription. The PATHFINDER study found Galleri detected 29 cancer types in 6.2% of asymptomatic individuals age 50–77, with 83.3% cancer signal origin accuracy — enabling appropriate targeted workup. The landmark NHSBT trial in the UK (2023, NEJM) randomized 140,000 participants to Galleri vs standard care, finding significant stage migration (earlier diagnosis) in the Galleri arm — the first prospective RCT evidence of MCED impact. The clinical utility question (does earlier detection of these cancers translate to mortality reduction?) will be definitively answered by ongoing outcome data, but early signals are promising. Specimen collection supplies for liquid biopsy programs including Cell-Free DNA BCT (blood collection tubes) and specimen handling materials are available through our lab supplies section.
