Abstract 7499: Circulating tumor cell enumeration and protein expression by CapioCyte and Allegro Plus imaging

Abstract Radiation or chemoradiation followed by surgical resection is the current standard of therapy for many diseases. These treatments are increasingly supplemented with monoclonal antibodies, such as epidermal growth factor receptor (EGFR) -targeting and programmed death ligand 1 (PD-L1) checkpoint-blocking antibodies. The use of these therapies is typically dependent on solid tissue biopsy to confirm elevated expression of these markers in the solid tumor, which carries complications and may only be sampled at diagnosis. In contrast, a liquid biopsy may detect these markers with minimal invasiveness and at multiple points throughout treatment and recovery. Here, we describe the development of an automated and integrated workflow for circulating tumor cell (CTC) analysis. We previously demonstrated that the CapioCyte method is a highly sensitive approach for enrichment of CTCs using a combination of biomimetic rolling on recombinant E-selectin and antibody-mediated capture on a nanostructured polymer surface within a flow chamber for capture. Here we report a fully automated CapioCyte instrument for CTC purification and immunofluorescence staining using epithelial, white blood cell and nuclear makers to identify and distinguish CTCs from WBCs while also quantifying EGFR or PD-L1 presence on respective CTCs. The immunostaining conditions were developed and validated for high analytical sensitivity and specificity using cell lines and health donor white blood cells with known biomarker status. The final assay conditions were transferred to the CapioCyte for automated immunostaining. CapioCyte enriched and stained CTC samples are paired with the BioView Allegro Plus platform, an imaging and analysis solution using machine learning and customized algorithms for automated imaging and CTC candidate identification based on high-resolution Z-stack images. The reported comprehensive and automated workflow was used to enumerate CTCs in patients with non-small cell lung carcinoma (NSCLC) in a feasibility cohort. Median CTC counts from NSCLC patients was 7. 5 CTC/ml (n=26, mean 51. 7, range 0. 3 - 406. 2). Studies are on-going to expand the cohort including testing blood from head and neck cancer patients and respective EGFR and PD-L1 status. The combined and automated CapioCyte-Allegro Plus workflow shows great potential for routine quantification of CTCs and EGFR and PD-L1 status. Citation Format: Ju-heon Lim, Chassidy Johnson, Tal Kaplan, Michael J. Poellmann, Yuval Harari, Elad Kfir, Andrew Z. Wang, Seungpyo Hong. Circulating tumor cell enumeration and protein expression by CapioCyte and Allegro Plus imaging abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 7499.