Myriad Genetics has expanded the availability of its Precise MRD™ test to patients with breast, colorectal, and renal cancers, providing an ultrasensitive method for tracking circulating tumor DNA (ctDNA). According to the June 23, 2026, company announcement, the test uses whole-genome sequencing to monitor disease status across the cancer care continuum, potentially impacting the treatment paths for more than 6 million individuals currently living with these diagnoses in the United States.
How Does Molecular Residual Disease Testing Work?
Precise MRD functions by creating a personalized molecular panel for each patient, tracking up to 1,000 unique genetic variants. By analyzing plasma samples, the test detects ctDNA—small fragments of tumor DNA shed into the bloodstream—even in low-shedding tumors where traditional imaging might miss residual disease. According to Myriad Genetics Chief Commercial Officer Brian Donnelly, this quantitative view allows clinicians to adjust surveillance and treatment strategies based on real-time molecular data rather than waiting for physical tumor growth.
What Does the MONITOR-Breast Study Reveal?
Recent clinical data published in Future Oncology highlights the efficacy of serial monitoring in breast cancer patients. The MONITOR-Breast study, which followed 154 patients with Stage I–III breast cancer, found that frequent sampling outperformed single-timepoint assessments. According to Myriad Genetics Chief Scientific Officer Dale Muzzey, the study identified 44% more patients at risk for residual disease through serial testing than by relying on post-treatment testing alone.
The study reported several key performance metrics:
- Specificity: The test predicted pathological complete response (pCR) with 100% specificity.
- Baseline Detection: ctDNA was identified in 93% of patients at the start of treatment.
- Prognostic Value: Patients testing positive for ctDNA after neoadjuvant therapy were 47 times more likely to remain positive after surgery.
Why Is Longitudinal Testing Becoming the Standard?
The shift toward serial monitoring addresses a persistent challenge in oncology: the “low-shedding” tumor. Traditional tests often fail when tumors release minimal DNA into the blood. By utilizing a whole-genome, tumor-informed approach, Precise MRD maintains sensitivity across various disease settings. While previous diagnostic methods often relied on static snapshots, the current industry trend—as evidenced by the Myriad data—favors dynamic tracking. This allows doctors to distinguish between patients who have cleared the disease and those who show persistent or intermittent positivity, the latter of whom are at a higher risk of recurrence.
Frequently Asked Questions
What types of cancer can Precise MRD detect?
As of June 2026, Myriad Genetics has expanded the test to include breast, colorectal, and renal cancers.
How does this test differ from a standard biopsy?
A biopsy is typically a tissue-based, one-time sample. Precise MRD is a “liquid biopsy” that uses blood samples to track genetic changes over time, allowing for continuous monitoring during and after treatment.
Can this test be used for all stages of cancer?
The current data focuses on Stage I–III breast cancer, though the test is designed for use throughout the cancer care continuum, including neoadjuvant therapy, post-surgical assessment, and long-term surveillance.
Is this test available in all clinical settings?
Myriad Genetics states that the test is designed to integrate into existing oncology workflows, meaning it can be ordered by healthcare providers in both academic and community-based medical centers.
Are you a healthcare provider interested in implementing molecular monitoring, or a patient looking to understand your surveillance options? Explore the Myriad Genetics oncology resources to learn more about how ctDNA testing is changing clinical decision-making.
