- [Resource Hub](/) - [Resource](/?resource-type=poster#library) - Validation of an assay to detect programmed death-ligand 1 (PD-L1) expression on circulating tumor cells # Validation of an assay to detect programmed death-ligand 1 (PD-L1) expression on circulating tumor cells PD-L1 status is usually read from a tissue biopsy, where spatial and temporal heterogeneity can obscure it; this TriCon 2020 poster reports the analytical validation of the RarePlex PD-L1 CTC Panel Kit, an immunofluorescence assay that enumerates circulating tumor cells and scores PD-L1 on each cell individually. Presented by RareCyte and University of Washington. Read or download to see: - Analytical performance was measured cell line by cell line against a single MFI threshold of 500. On the PD-L1-negative HAP-1 line specificity was 0.974; on the PD-L1-high SW900 line sensitivity reached 0.987 and accuracy 0.980; on the PD-L1-low H1650 line sensitivity fell to 0.694 and accuracy to 0.834 — the cost a single fixed threshold carries on dim expressers. - Nucleated blood cells go onto the slide intact, and 4 fluorescence channels decide what each one is. Blood collected in AccuCyte Blood Collection Tubes is density-separated onto slides, stained for a nuclear dye, CK/EpCAM, CD45 and PD-L1, then scanned on a CyteFinder instrument; candidate CTCs are rank-scored on several hundred image-based features by a machine-learning model trained on more than 1000 clinical CTCs, then confirmed by blinded certified reviewers. - In patient blood, PD-L1-positive and PD-L1-negative CTCs turned up in the same draw. One breast, one lung and one prostate cancer sample each yielded PD-L1-positive CTCs, with representative single-cell MFIs of 1689, 2153 and 823 against patient-matched negative cells at 295, 78 and 128 — PD-L1 status varying from cell to cell inside a single patient’s sample. [Download poster](https://cdn.sanity.io/files/s3p6uqps/production/d6eac85be7627ae4445c6583acad89fea879177d.pdf) Your browser doesn’t support embedded PDFs. [Download the poster](https://cdn.sanity.io/files/s3p6uqps/production/d6eac85be7627ae4445c6583acad89fea879177d.pdf) to view it. [Back to all resources](/#library) ## Related resources [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) [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) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/360436f6c2d14d82f253816115d89e2ace4233e2.pdf) CyteFinder 2024 ### Development and analytic validation of an ARv7 / PSMA dual biomarker circulating tumor cell assay [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/360436f6c2d14d82f253816115d89e2ace4233e2.pdf) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/f24e3e19abdbc04fe6d294d046d9639ecd410e6e.pdf) CyteFinder 2024 ### Development and validation of an assay for the characterization of SSTR2 expression on CTCs from liquid biopsies [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/f24e3e19abdbc04fe6d294d046d9639ecd410e6e.pdf) [Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC11863877/) CyteFinder The Journal of Liquid Biopsy 2023 ### Liquid biopsy kinetics and detection of ERBB2 amplification/HER2-positivity in refractory hepatocellular carcinoma [View Publication](https://pmc.ncbi.nlm.nih.gov/articles/PMC11863877/) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/b4fe65d132e5579cb5e0a30c9bee5d7ff7f632ab.pdf) CyteFinder 2023 ### Novel method for the detection and evaluation of disease biomarkers on white blood cells from liquid biopsies [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/b4fe65d132e5579cb5e0a30c9bee5d7ff7f632ab.pdf) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/51dd5a4aee911d671443d768abcfc0b4f83899e8.pdf) CyteFinder 2020 ### Validation of a dual-marker ARv7/SYP assay for CTC characterization [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/51dd5a4aee911d671443d768abcfc0b4f83899e8.pdf) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/558dd9bd9ab2fa4c95bbc225309f5026bd3b7094.pdf) CyteFinder 2020 ### Analytic validation of an assay to detect androgen receptor splice variant ARv7 protein expression on circulating tumor cells from prostate cancer patients [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/558dd9bd9ab2fa4c95bbc225309f5026bd3b7094.pdf) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/600f37993438d761629a40034f7702ebe3e46ee3.pdf) CyteFinder 2020 ### Investigation of custom biomarkers on circulating tumor cells from clinical samples using RarePlex Developer Kits [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/600f37993438d761629a40034f7702ebe3e46ee3.pdf) [Video](https://www.youtube.com/watch?v=A0dhlNEaohs) CyteFinder 2020 ### RarePlex Assays: Design and Analytical Validation [Watch Video](https://www.youtube.com/watch?v=A0dhlNEaohs) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/5962be5f1b2b288f2c069f7bd7b54890839f426a.pdf) CyteFinder 2019 ### Custom biomarker investigation of circulating tumor cells using RarePlex® Developer Kits [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/5962be5f1b2b288f2c069f7bd7b54890839f426a.pdf) [Poster](https://cdn.sanity.io/files/s3p6uqps/production/886b7272733f331d2bd933c9cfa2bb97ce0e9542.pdf) CyteFinder 2018 ### Novel multi-parameter assays for investigational phenotyping of circulating tumor cells [Download Poster](https://cdn.sanity.io/files/s3p6uqps/production/886b7272733f331d2bd933c9cfa2bb97ce0e9542.pdf)