Abstract 2180: Utilization of multiparameter flow cytometry for immune monitoring of tumor infiltrating lymphocytes isolated from fresh tumor tissue

Abstract A multiparameter flow cytometry panel was designed to assess immune populations infiltrating solid tumors. Obtaining viable immune cells from fresh tissue for analysis can be challenging, however, using optimized shipping conditions and isolation procedures developed by Precision for Medicine (PfM) for fresh solid tumor biopsy pieces or fine needle aspirates, a variety of solid tumor indications, including melanoma, colorectal adenocarcinoma, sarcoma, triple negative breast cancer, renal cancer, head & neck cancer, lung cancer and stomach cancer, were analyzed by flow cytometry. Following overnight shipment from collection sites to PfM’s laboratory, a real time sample processing procedure using a mechanical dissociation protocol followed by multiparametric flow cytometric analysis was performed. Post dissociation of tumor samples, cell viabilities ranged between 50-90%, and the sample quality was sufficient for flow cytometric analysis of tumor infiltrating lymphocytes (TILs). This analysis revealed that the frequency and phenotype of infiltrating immune cells could be assessed successfully. It was observed that variations in the frequency and phenotype of infiltrating cells were present in the tumor tissues. This study shows that real time multiparametric flow cytometric analysis of fresh tumor tissues, within 48 hours of collection, can be implemented in clinical trials with careful planning and consideration of clinical operations. This is of value for early phase clinical studies evaluating the impact of immune therapies on immune cell infiltration within solid tumors, and provides an additional immune monitoring tool. Citation Format: Rachel Owen, Angelina Bisconte, Deborah Phippard. Utilization of multiparameter flow cytometry for immune monitoring of tumor infiltrating lymphocytes isolated from fresh tumor tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2180.