Novel Assay, Developed on Akoya PhenoImager HT Platform with Opal Chemistry, Becomes First to Predict Both Locoregional Recurrence Risk and Radiation Therapy Benefit in Early-Stage Invasive Breast Cancer

PreludeDx^® and Quanterix Corporation (NASDAQ:QTRX) today highlighted that AidaBREAST™, the first multi-omic assay to predict both locoregional recurrence risk and radiation therapy benefit in early-stage invasive breast cancer, was developed on Akoya PhenoImager^® HT platform using Opal™ chemistry. This marks a significant milestone in the clinical translation of spatial proteomics.

The validation of AidaBREAST included 922 hormone receptor-positive, HER2-negative invasive breast cancer patients across four academic and clinical centers in the United States and Sweden, with a median follow-up of ~10 years. The study demonstrated the test to be both prognostic for 10-year locoregional recurrence risk and predictive for radiation therapy benefit, two capabilities not previously available to clinicians in a single assay for early-stage invasive breast cancer.

AidaBREAST leverages the PhenoImager HT platform and Opal chemistry to obtain spatial multiplex protein expression, which is then integrated with targeted next-generation RNA sequencing for comprehensive assessment of tumor biology.

"AidaBREAST harnesses the power of spatial biology and AI to provide unique insights into the tumor and immune-microenvironment not available from clinicopathology," said Karuna Mittal, PhD, Senior Director of Research and Development at PreludeDx and co-author of the published study. "For the first time, oncologists have a tool that tells them not just how likely a patient is to recur, but whether radiation therapy is actually going to help that specific patient. That is a meaningful shift in how we can better inform treatment decisions."

"AidaBREAST is exactly the kind of scientific achievement that demonstrates what is possible when spatial proteomics is applied with rigor and clinical intent," said Everett Cunningham, Chief Executive Officer of Quanterix. "PreludeDx's ability to develop a truly novel tool on our PhenoImager HT platform – that also performs reliably and reproducibly across multiple institutions and years of archived tissue, speaks to the immediate opportunity for spatial proteomics in clinical oncology."

AACR Annual Meeting 2026

Dr. Karuna Mittal will present the AidaBREAST study findings at the Quanterix booth 2028 at the AACR Annual Meeting 2026 on Tuesday, April 21st from 11:45 to 12:00 PM, with a focus on the role of spatial proteomics in locoregional recurrence risk assessment and radiation therapy decision-making. Attendees are invited to visit booth 2028 to learn more.

For more information visit: https://www.quanterix.com/events-conferences/aacr-american-association-for-cancer-research-annual-meeting-2026/

About AidaBREAST™ for Early-Stage Breast Cancer

AidaBREAST™ is the only risk assessment test for patients with stage I,IIa breast cancer that predicts radiation therapy benefit. The next-generation multi-omic assay developed by PreludeDx uses advanced spatial biology technology combining multiplex protein expression with targeted next-generation RNA sequencing to provide a comprehensive assessment of a patient's tumor biology. Leveraging the power of artificial intelligence, the assay integrates these complex data to generate a patient's individualized risk assessment for 10-year locoregional recurrence and predict their benefit from radiation therapy. This innovative approach enables physicians to move beyond traditional measures offering patients personalized results with new insights into recurrence risk and radiation therapy benefit. This new information helps patients and their physicians to make more informed treatment decisions.

About PreludeDx

PreludeDx is a leading personalized breast cancer diagnostics company serving patients and physicians worldwide. Founded in 2009 with technology from the University of California San Francisco, PreludeDx is dedicated to developing precision breast cancer tools that impact treatment decisions. The company's mission is to provide innovative technologies that improve patient outcomes and reduce healthcare costs. Before making a treatment decision, Know Your Risk™, Know Your Benefit. For more information on how PreludeDx is making a difference for patients, please visit the Company's website: https://preludedx.com and follow us on X, LinkedIn, Instagram and Facebook.

About Quanterix

Quanterix is a global leader in ultra-sensitive biomarker detection, enabling breakthroughs in disease research, diagnostics, and drug development. Its proprietary Simoa^® technology delivers industry-leading sensitivity, allowing researchers to detect and quantify biomarkers in blood and other fluids at concentrations far below traditional limits. With approximately 6,300 peer-reviewed publications, Quanterix has been a trusted partner to the scientific community for nearly two decades. In 2025, Quanterix acquired Akoya Biosciences, The Spatial Biology Company^®, adding multiplexed tissue imaging with single-cell resolution to its portfolio and 1,439 installed instruments. Together, the combined company offers a uniquely integrated platform that connects biology across blood and tissue -- advancing precision medicine from discovery to diagnostics. Learn more at www.quanterix.com.

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Media Contact — PreludeDx

Martin Sandgren

Klover Communications

press@klovercommunications.com

Media Contact — Quanterix

media@quanterix.com

Investor Relations Contact — Quanterix

Joshua Young

jyoung@quanterix.com

AidaBREAST™ Multi-Omic Assay Demonstrates Spatial Proteomics for Clinical Oncology