Serum Detect, Inc.

Dear Colleagues and Friends, Although Serum Detect has shut down, we are proud to share the publication of our manuscript, “Circulating T-cell receptor repertoire for cancer early detection,” in Nature’s npj Precision Oncology. You can read the article here: https://rdcu.be/ewYq9 This study describes the implementation of Serum Detect’s vision: harnessing the immune system to improve cancer early detection. We demonstrated that circulating T-cell receptor (TCR) repertoire analysis can complement existing biomarkers to significantly increase sensitivity for detecting early-stage lung cancer as part of a multi-analyte liquid biopsy approach. What makes this work especially meaningful is the outstanding collaboration behind it. The study brought together scientists and clinicians from Serum Detect, Universidad de Navarra, Rush University, Dana-Farber Cancer Institute, Brigham and Women’s Hospital, and others, spanning multiple academic medical centers in the U.S. and Spain. We are deeply grateful to everyone who contributed to this research — especially the patients who generously donated samples — and we hope these findings support continued innovation in the field. Thank you to our co-authors, collaborators, and the entire extended team. Sincerely, Roman Yelensky, Ph.D. Founder & CEO (former) Serum Detect

Dear Colleagues and Friends, I’m writing today to share difficult news: Serum Detect has ceased operations and will be winding down in the coming weeks. When we founded Serum, our vision was bold — to advance early cancer detection by harnessing the immune system's response, using innovative T-cell receptor (TCR) repertoire analysis. We set out to complement and enhance existing liquid biopsy approaches, driven by the belief that we could help detect cancer earlier, when treatment is most effective and lives can be saved. Our team made meaningful progress, including the development of novel assays and computational techniques to identify cancer-linked TCR repertoire functional units. We were honored to share promising early data at multiple scientific conferences and are deeply grateful for the interest and support we received from partners and the broader community. After thoroughly exploring all strategic options, we made the difficult decision to discontinue the company’s operations. This choice was not made lightly, but reflects the realities of a challenging fundraising environment — despite the strength of our science and team. To our employees, investors, collaborators, and advisors — thank you. Your support made this journey possible, and your belief in our mission gave us purpose every day. Though Serum Detect has come to a close, I remain committed to the pursuit of better diagnostic tools for cancer and hope that our work will inspire and support future innovation in this space. Sincerely, Roman Yelensky, Ph.D. Founder & CEO Serum Detect