Quantitative Image Analysis Of Pd-L1, Cd8, Cd3, Cd68 And Foxp3 Protein Expression In Lung And Bladder Cancer Specimens By Fully Automated Multiplex Fluorescence Immunohistochemistry.

11590Background: Expression of PD-L1 in tumor cells (TC) and infiltrating immune cells (IC) allows TCs to escape from host’s antitumor immunity by inducing tolerance among tumor-specific T cells. Treatment with the anti-PD-L1 agent atezolizumab has been shown to result in significantly improved outcomes in patients with advanced urothelial bladder cancer (UBC) and non-small cell lung cancer (NSCLC). Higher levels of PD-L1-expression have been associated with a greater efficacy. An ideal assessment of TCs and ICs in patients with anti-PD-L1 treatment requires simultaneous immunohistochemistry (IHC) detection of multiple biomarkers. Methods: A fully automated 5-Plex fluorescence IHC assay was developed on the BenchMark ULTRA automated slide stainer using rabbit monoclonal antibodies PD-L1 (SP142), CD3, CD8, CD68 and FoxP3 by tyramide signal amplification. The stained slides were scanned with Zeiss AXIO Z1, and analyzed with in-house digital image analysis tools. Results: A cohort of archived NSCLC and UBC s...