Fourteen City of Hope sites across the U.S. participating in research using the Haystack MRD ctDNA Test in patients with breast, colorectal, ovarian, and prostate cancer

SECAUCUS, N.J. and LOS ANGELES, April 16, 2026 /PRNewswire/ -- Quest Diagnostics (NYSE: DGX), a leading provider of diagnostic information services, today announced that City of Hope, one of the largest and most advanced cancer research and treatment organizations in the United States, is implementing Haystack MRD^®, a highly accurate circulating-tumor DNA (ctDNA) minimal residual disease (MRD) test, for clinical trial participants with solid tumor cancers to help guide disease management for patients being treated for breast, colorectal, ovarian and prostate cancer. The multi-year research program is expected to serve approximately 500 patients with thousands of longitudinal measurements from fourteen City of Hope sites across the country, including in the Los Angeles, Orange County, Chicago, Phoenix, and Atlanta areas.

"City of Hope brings together the scientific expertise, clinical infrastructure, and advanced technology needed to evaluate emerging approaches that can meaningfully improve cancer care and health outcomes for patients," said Cristian Tomasetti, Ph.D, Professor and Director, Center for Cancer Prevention, Early Detection and Monitoring, City of Hope. "We see liquid biopsy as an important frontier in oncology and aim to leverage the most accurate and effective commercially available ctDNA assays while also working to develop effective early detection platforms. We are excited to study how Haystack MRD might inform treatment decisions across several solid tumor types."

The City of Hope clinical trials are investigating Haystack MRD across patient management settings, including neoadjuvant, adjuvant and post-treatment surveillance. The research is evaluating if the test can detect minimal residual disease, monitor treatment response, and identify recurrence earlier than standard imaging modalities.

"New blood test technologies can make a significant difference for a patient. For example, they may help determine that a surgery was able to fully remove the cancer, thereby sparing chemotherapy treatment," added Dr. Tomasetti, Professor in the Early Detection and Prevention Division at the Translational Genomics Research Institute (TGen), part of City of Hope.

"City of Hope is one of the nation's foremost cancer centers, with a century-long commitment to advancing cancer care through both research and clinical excellence, and we have built a strong relationship with them over time," said Dan Edelstein, Vice President and General Manager of Haystack Oncology, a Quest Diagnostics company. "Haystack MRD is designed to help clinicians and their patients act earlier with greater confidence, based on the principle that cancer survivors and their care teams should be able to make proactive, not reactive, healthcare decisions. We believe the research collaboration will generate important evidence supporting the role of Haystack MRD in informing patient management across multiple solid tumor settings."

About ctDNA MRD
A growing body of research underscores the value of ctDNA-based MRD testing for identifying residual or recurring cancer in solid tumors. By detecting trace amounts of tumor-derived DNA in the bloodstream, ctDNA MRD testing can reveal molecular evidence of disease recurrence months before it becomes apparent through imaging or other conventional monitoring methods. This early insight can help clinicians tailor surveillance strategies, adjust treatment plans, and potentially intervene before disease progression becomes clinically evident. Nearly all oncologists (96%) in a survey by Harris Poll for Quest Diagnostics said MRD testing has the potential to identify cancer recurrence earlier than other current methods. In 2025, the FDA granted the Haystack MRD Dx test Breakthrough Device Designation for use in Stage II colorectal cancer.

About Haystack Oncology
Haystack Oncology represents the culmination of over 20 years of collaboration to advance technical and clinical development in liquid biopsy technologies by cancer genomics pioneers at Johns Hopkins School of Medicine. The company, a wholly owned subsidiary of Quest Diagnostics, developed Haystack MRD, a tumor-informed, next-generation MRD test that detects ultralow levels of ctDNA to uncover residual or recurrent disease with exceptional sensitivity and specificity. Haystack Oncology works with biopharmaceutical companies to accelerate and inform clinical development programs and advance important therapeutics to global markets, from early phase clinical development to companion diagnostics. Haystack MRD was developed and validated in a CLIA-certified laboratory and is available for commercial use as a lab-developed test (LDT) by Quest Diagnostics. The FDA granted Haystack MRD Breakthrough Device Designation in 2025 for use in Stage II colorectal cancer. Haystack MRD is also available for clinical trials as an investigational device by Haystack Oncology in laboratories located in Baltimore, Maryland; Hamburg, Germany; and Helsinki, Finland. www.haystackmrd.com

About Quest Diagnostics
Quest Diagnostics works across healthcare to create a healthier world, one life at a time. We connect people, from clinicians to consumers, with laboratory insights that illuminate a path to better health. With a focus on delivering smarter, simpler testing, we help reveal new avenues to identify and treat disease, empower healthy behaviors and improve healthcare management. Quest Diagnostics serves half the physicians and hospitals in the United States and one in three American adults each year, and our nearly 57,000 employees work together to deliver diagnostic insights that inspire actions to transform lives. www.QuestDiagnostics.com

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SOURCE Quest Diagnostics