Conference Abstracts - 5th Binaytara Precision Oncology Summit: Redefining Cancer Treatment with Molecular Targeted Strategies
Vol. 5, Issue Supplement 1, 2025 · S1-2
Prognostic value of Nectin-4 and Trop2 extracellular vesicles for plasma and urine samples collected from patients with bladder cancer just prior to cystectomy
Albert Jang, MD,Yohan Kim, PhD,Emily Bauer, BS,Prabin Thapa, MS,Igor Frank, MD,Paras Shah, MD,John Cheville, MD,Jacob Orme, MD, PhD,Fabrice Lucien, PhD
Submission received: 2025-08-14 / Accepted: 2025-09-03 / Published: 2025-09-26
Abstract
Background
Extracellular vesicles (EVs) hold promise as non-invasive cancer biomarkers, but their clinical utility in bladder cancer remains to be investigated. Nectin-4 and Trop2 are cell surface proteins overexpressed in bladder cancer and therapeutic targets of FDA-approved antibody-drug conjugates. Here, we analyzed the levels of EVs positive for Nectin-4 and Trop2 and their association with clinicopathological features in a cohort of patients diagnosed with bladder cancer and treated with radical cystectomy.
Methods
Blood and urine samples were collected within 48 hours pre-cystectomy from 107 patients diagnosed with locally or locally advanced bladder cancer between 2006 and 2013 at Mayo Clinic. Samples from 20 healthy donors (HD) collected between 2019-2022 were included as controls. They were stored at –70°C and then thawed in spring 2025 for analysis. EVs were stained with fluorescent antibodies against Nectin-4 (enfortumab) and Trop2 (sacituzumab) and quantified by nanoscale flow cytometry. Immunohistochemistry was used to measure protein expression in matched surgical tissue specimens.
Results
For 107 patients, there were 83% men, 93% Caucasian, 25% variant histology, 13% received neoadjuvant chemotherapy, and 20% received adjuvant chemotherapy. Median time to recurrence was 0.8 years. Median overall survival (mOS) after cystectomy was 2.9 years. Median Nectin-4 H-score was 90 (83% cases had H-score>5). Median Trop2 H-score was 300 (95%; H-score>5). No correlation was found between EV levels and tissue expression. Higher urine Trop2 EV concentrations were found in bladder cancer patients compared to healthy donors (p<0.0001). Thirty-five (33%) patients had pTa/Tis/T1/T2pN0, while 37 patients (35%) had pT1-4pN1-3, with mOS 13.8 vs 1.3 years (HR 0.22, p<0.0001), respectively. The pT1-4pN1-3 cohort had significantly higher plasma levels of Nectin-4 and Trop2 EVs over the pTa/Tis/T1/T2pN0 cohort (3.5x107 vs 1.4x107, p=0.0024; and 7.2x106 vs 4.1x106, p=0.0056; respectively). No significant differences in EVs/mL were seen for these cohorts when comparing total plasma (p=0.603), urine nectin-4 (p=0.276), urine trop2 (p=0.071), and total urine (p=0.588).
Conclusion
Pre-cystectomy Nectin-4 and Trop2 plasma EVs may be potential non-invasive biomarkers for bladder cancer. These are exploratory findings limited by sample size, timing of collection, and specimen quality. Validation in larger sample sizes and prospective cohorts is underway.