Highly Accurate Detection of Circulating Tumor DNA for Monitoring Minimal Residual Disease in Solid Tumors: Analytical and Clinical Validation of the Haystack MRD Assay | Maria Clark et al. | ResearchPod

Transcript: Highly Accurate Detection of Circulating Tumor DNA for Monitoring Minimal Residual Disease in Solid Tumors: Analytical and Clinical Validation of the Haystack MRD Assay

Alex: After colon cancer surgery, ten patients tested positive for leftover tumor DNA, and all ten relapsed within three years. Everyone who tested negative stayed cancer-free over that same window.

Sam: That's a clean split. Whose result is it, and what kind of study produced it?

Alex: It's a validation paper in the Journal of Molecular Diagnostics for a blood test called Haystack MRD. The authors are mostly from Quest Diagnostics and Haystack Oncology, the companies behind the test, plus collaborators in Melbourne. So it's the developer validating its own assay, which is normal for diagnostics, but worth keeping in mind.

Sam: I don't work in oncology. Why should someone outside the field care about one more blood test?

Alex: Because it targets a real decision. After surgery, some patients still carry minimal residual disease, meaning cancer cells too few to see on a scan. A reliable test could tell doctors who needs chemotherapy and who could safely skip it. We'll cover how the test hunts for such rare signal, what the numbers show, and where the evidence thins out.

Sam: Start with the hunt. Why is this hard?

Alex: Tumors shed circulating tumor DNA, small fragments of their DNA, into the blood. After surgery there may be almost none, buried among normal DNA from healthy cells. That's the needle in the haystack the name refers to. The real enemy is noise. Sequencing makes errors, and an error can look exactly like a tumor mutation.

Sam: The obvious fix is to look for more mutations at once. Doesn't that just help?

Alex: The authors flag the catch. Track more mutations and background noise grows with the number of molecules you interrogate. So more targets only helps if you suppress errors hard. That's the design problem this assay is built around.

Sam: So how do they suppress them?

Alex: Two steps. First, it's tumor-informed: they sequence the patient's own tumor and pick up to 50 of its mutations for a personalized panel. They avoid noisy stretches of the genome, and they drop mutations in genes linked to clonal hematopoiesis, which is when ordinary blood cells pick up mutations with age. Second, the chemistry, called SaferSeqS, tags every original DNA molecule. A mutation only counts if it shows up across most copies of that molecule, and on both of its complementary strands.

Sam: So a random copying error on one strand gets thrown out, because the matching strand won't carry it.

Alex: That's the logic. They call those two-strand hits Duo Mutations. Then a sample's cutoff is set individually, based on that panel's expected noise and how much DNA went in. The authors even note this lets them call some positives below the formal detection limit.

Highly Accurate Detection of Circulating Tumor DNA for Monitoring Minimal Residual Disease in Solid Tumors: Analytical and Clinical Validation of the Haystack MRD Assay

Maria Clark, Ramadevi Prathapam, Kelli S. Bramlett, Annett Helfrich-Kröger, Robyn T. Sussman, Hee Jung Hwang, Robert Querfurth, Kristen J. Champion, Frank Holtrup, Thomas P. Slavin, Dagmar Küntzlin-Schierloh, Angela Koenig, Ithiel James Frame, Irina Maramica, Hannah Quinn, Jeremy B. Kaplan, Daniel H. Mehnert, Chodon Sass, Christina L. Cleveland, Christopher Elzinga, Justin DeGrazia, Taraneh Angeloni, Dana Goos-Root, Sheila Powers, Jesus Izaguirre Carbonell, Roslynn Stirzaker, Marlyse A. Debrincat, Matthew Chapman, Evan Brown, Matthew Ryder, Peter Gibbs, Hillary S. Sloane, Daniel Edelstein, Jeanne Tie

Oct 12, 2026·7:30·user_upload

Minimal Residual Disease (MRD)Circulating Tumor DNA (ctDNA)Next-Generation Sequencing (NGS)Haystack MRD AssayAnalytical ValidationTarget Enrichment Chemistry

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8 min

Summary

Overview

This paper reports the analytical and clinical validation of Haystack MRD, a personalized, tumor-informed liquid biopsy assay designed to detect minimal residual disease (MRD) in patients with solid tumors. By tracking up to 50 patient-specific somatic mutations, the assay aims to distinguish genuine circulating tumor DNA (ctDNA) from background biological and technical noise, addressing the significant challenge of detecting sparse tumor-derived molecules in peripheral blood.

Analytical Approach

The researchers validated the assay using reference materials and clinical specimens across more than 20 tumor histologies. A key feature of the method is the use of SaferSeqS target enrichment chemistry, which minimizes false positives by requiring mutations to be observed on both the sense and antisense strands (termed 'Duo Mutations') and across unique molecular identifier families. The study established a limit of detection (LoD95) of 0.063 mean ctDNA molecules/mL and an analytical measurement range of 0.25 to 1000 mean ctDNA molecules/mL, providing a quantitative framework for longitudinal monitoring.

Clinical Performance

In a clinical validation cohort comprising patients with stage II and III colorectal cancer, the test demonstrated exceptional accuracy. At a 3-year follow-up, the assay achieved 100% sensitivity and 100% specificity for predicting recurrence. Extended 5-year follow-up data yielded 83.3% sensitivity while maintaining 100% specificity, consistently outperforming traditional carcinoembryonic antigen (CEA) measurements. Real-world evaluation across 27 different solid tumor types confirmed the assay's robustness in diverse clinical scenarios.

Why It Matters

Effective MRD detection is critical for guiding postoperative management, allowing clinicians to identify patients at high risk of recurrence who may benefit from intensified adjuvant therapy, while potentially sparing low-risk patients from unnecessary toxicity. Because the assay provides precise quantitative measurements, it serves as a reliable tool for serial monitoring, enabling early detection of treatment response or molecular progression.

Key Terms and Definitions

Minimal Residual Disease (MRD) — the presence of trace amounts of residual cancer cells or ctDNA remaining after curative-intent treatment.
Tumor-Informed Assay — a testing approach that uses an initial analysis of a patient's primary tumor to identify specific mutations, which are then used to design a personalized panel for subsequent plasma monitoring.
Mean ctDNA Molecules/mL — a unit of measure for ctDNA concentration that normalizes signal to plasma volume rather than to total cell-free DNA, reducing interpretive bias from background DNA fluctuations.
Duo Mutation — a mutation that must be observed on both the sense and antisense strands of a unique cfDNA molecule to be called as a positive signal, used as an error-suppression technique.
Analytical Measurement Range (AMR) — the range of concentrations over which the assay has been demonstrated to provide accurate, linear, and precise results.

Highly Accurate Detection of Circulating Tumor DNA for Monitoring Minimal Residual Disease in Solid Tumors: Analytical and Clinical Validation of the Haystack MRD Assay: Research Paper Podcast