- [Resource Hub](/) - [Publication](/?resource-type=publication#library) - Comprehensive Longitudinal Linear Mixed Modelling of CTCs Illuminates the Role of Trop2, EpCAM, and CD45 in CTC Clustering and Metastasis # Comprehensive Longitudinal Linear Mixed Modelling of CTCs Illuminates the Role of Trop2, EpCAM, and CD45 in CTC Clustering and Metastasis Merkley SD, Kang H, Brown-Glaberman U, Marchetti D. Cancers . 2025;17(16):2717. DOI [10.3390/cancers17162717](https://doi.org/10.3390/cancers17162717). How to cite ### AMA Merkley SD, Kang H, Brown-Glaberman U, Marchetti D. Comprehensive Longitudinal Linear Mixed Modelling of CTCs Illuminates the Role of Trop2, EpCAM, and CD45 in CTC Clustering and Metastasis. Cancers . 2025;17(16):2717. doi:10.3390/cancers17162717 ### APA Merkley, S. D., Kang, H., Brown-Glaberman, U., & Marchetti, D. (2025). Comprehensive Longitudinal Linear Mixed Modelling of CTCs Illuminates the Role of Trop2, EpCAM, and CD45 in CTC Clustering and Metastasis. Cancers , 17(16), 2717. https://doi.org/10.3390/cancers17162717 ### BibTeX @article{merkley2025comprehensive, title = {Comprehensive Longitudinal Linear Mixed Modelling of CTCs Illuminates the Role of Trop2, EpCAM, and CD45 in CTC Clustering and Metastasis}, author = {Merkley, Seth D. and Kang, Huining and Brown-Glaberman, Ursa and Marchetti, Dario}, journal = {Cancers}, volume = {17}, number = {16}, pages = {2717}, year = {2025}, doi = {10.3390/cancers17162717} } Circulating tumor cells are the cells that carry a cancer from its primary site into the bloodstream and on to distant organs, and their presence signals a poorer prognosis. But they vary widely between patients and even within one patient, and the classical way of spotting them — EpCAM-positive, cytokeratin-positive, CD45-negative — was built around epithelial tumors, so it can miss cells that have drifted toward a mesenchymal state. This team followed 51 metastatic breast cancer patients over 32 months, counting both classical and Trop2-positive circulating tumor cells across 305 blood samples and relating each marker to how the cells cluster. EpCAM, Trop2, and the presence of CD45-positive cells all predicted cluster size, while pan-cytokeratin did not, and EpCAM and larger clusters rose over time in HER2-positive but not hormone-receptor-positive cancers after metastasis was diagnosed. [Read publication at Cancers](https://doi.org/10.3390/cancers17162717) ## Key findings - Two circulating tumor cell populations were tracked across a 32-month longitudinal series. 305 blood samples from 51 metastatic breast cancer patients were scored — 205 samples from 51 patients for classical CTCs and 100 samples from 26 patients for Trop2+ CTCs — yielding more than 6,000 images for review. - EpCAM, Trop2, and CD45+ cells predicted CTC cluster size; pan-cytokeratin did not. Among the strong correlations (r ≥ 0.7), EpCAM+ CTCs and the presence of CD45+ cells tracked cluster presence and size — with a correlation of 0.78 between EpCAM+ CTCs and CD45+ cells — while pan-cytokeratin reached no strong correlation with any biomarker. - EpCAM and larger CTC clusters increased over time in HER2+ but not HR+ cancers after metastatic diagnosis. In the longitudinal model, slopes differed significantly between receptor subtypes for EpCAM (p = 0.02183) and for clusters of more than two cells (p = 0.00691), both rising in HER2+ disease while HR+ showed no significant change. ## CyteFinder II in the methods “All slides were scanned using the Cytefinder II® imaging platform and analyzed with CyteHub® software. Images output by CytHub were then quality-checked by trained technicians to confirm classification as individual CTCs and/or clusters.” — Merkley et al., Cancers (2025), Methods, “Sample Processing, Scanning, and Analysis” ## Why it matters for CyteFinder II users If you are weighing CyteFinder II for rare-cell work, look at what it carried here. Every slide in this 32-month study was scanned on the CyteFinder II platform, and the images it produced were analyzed in CyteHub to enumerate single CTCs and to classify each as a singlet or as a two-, three-, or larger-cell cluster. That cluster call is the unit the whole analysis rests on: the correlations with EpCAM, Trop2, and CD45, and the receptor-subtype trajectories over time, are all built from cluster presence and size read off these images. Two things follow for your own workflow. Because the entire nucleated-cell layer is laid onto the slide before scanning rather than captured on EpCAM first, the imaging step sees Trop2-positive and EpCAM-low cells that an enrichment step would have discarded. And because clusters are scored image by image with technician review, heterotypic CD45-positive configurations are counted rather than dissociated away. For a rare, heterogeneous population, that whole-slide readout is the point. [Back to all resources](/#library) ## Related resources [Publication](https://doi.org/10.1200/JCO.2026.44.16_suppl.5041) CyteFinder Journal of Clinical Oncology 2026 ### Clinical validation of circulating tumor cell synaptophysin and androgen receptor expression in metastatic prostate cancer phenotypes. [View Publication](https://doi.org/10.1200/JCO.2026.44.16_suppl.5041) [Video](https://www.youtube.com/watch?v=_oGC1KRVN2U) CyteFinder 2026 ### Dr. Pashtoon Kasi on the impact of circulating tumor cells on clinical research [Watch Video](https://www.youtube.com/watch?v=_oGC1KRVN2U) [Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC12881594/) CyteFinder Nature Communications 2026 ### Extracellular matrix mediates circulating tumor cell clustering in triple-negative breast cancer metastasis [View Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC12881594/) [Publication](https://doi.org/10.1016/j.ejso.2025.111357) CyteFinder European Journal of Surgical Oncology 2026 ### Circulating tumor cells predict relapse in head and neck mucosal squamous cell carcinoma [View Publication](https://doi.org/10.1016/j.ejso.2025.111357) [Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC12805936/) CyteFinder Cancer Research Communications 2026 ### Surface Marker Identification to Capture Live Circulating Tumor Cells in Metastatic Triple-Negative Breast Cancer [View Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC12805936/) [Publication](https://doi.org/10.1080/07366205.2025.2534299) CyteFinder BioTechniques 2025 ### A novel device for buffy coat collection [View Publication](https://doi.org/10.1080/07366205.2025.2534299) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/246a94d07c9a47c844784f113f57f4415bf84a5c.pdf) CyteFinder 2025 ### Development of a CTC Based Assay to Characterize MAOA Expression in Metastatic Prostate Cancer [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/246a94d07c9a47c844784f113f57f4415bf84a5c.pdf) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/43fb6d4a8510166e936d250b3bf172e2f669bfa3.pdf) CyteFinder 2025 ### Quantitative analysis of HER2, HER3, and γH2AX expression on circulating tumor cells for pharmacodynamic measurement in clinical trials [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/43fb6d4a8510166e936d250b3bf172e2f669bfa3.pdf) [Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC11985722/) CyteFinder Cellular and Molecular Life Sciences 2025 ### Portal venous circulating tumor cells as a biomarker for relapse prediction in resected pancreatic cancer [View Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC11985722/) [Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC12092302/) CyteFinder Nature Medicine 2025 ### Neoadjuvant triplet immune checkpoint blockade in newly diagnosed glioblastoma [View Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC12092302/) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/f6e029d0a3ad855ff644046c0b1c1c20cf771df2.pdf) CyteFinder Orion 2024 ### Next Gen Liquid Biopsy: Comprehensive Analysis from a Single Tube of Blood [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/f6e029d0a3ad855ff644046c0b1c1c20cf771df2.pdf) [Webinar](https://www.youtube.com/watch?v=vJ3YH4z1YKI) CyteFinder 2024 ### New Discoveries in HER2 Detection: A Novel Method of Multimodal Detection of HER2 from a Single Tube of Blood [Watch Webinar](https://www.youtube.com/watch?v=vJ3YH4z1YKI)