Abstract 1714: Profiling spatial signatures in the microenvironment of non-small cell lung carcinomas in immunotherapy responsive and resistant disease cohorts
Authors: Kulasinghe Arutha , Ma Ning , Monkman James , Mammadova Najiba , Braubach Oliver , O'Byrne Ken 
Published: June 2022

Abstract
The era of precision medicine has been powered in part by advancements in the field of immuno-oncology, which postulates that harnessing the body’s own immune system is key to eliminating cancer. Immunotherapies have, to date, revolutionised the field of oncology. The immune contexture of the tumour microenvironment (TME) is an important factor in dictating how well a tumour may respond to immune checkpoint inhibitors (ICI), but biomarker information alone is insufficient to design appropriate treatment strategies. Instead, we now understand that spatial classification of the immune contexture within the TME is foundational towards addressing how immunological composition and status dictates responses to therapy. In this project, we used a combination of high throughput and high-fidelity spatial biomarker detection strategies to thoroughly characterize the TME of non-small cell lung carcinoma tissue samples against outcomes for immunotherapy arm of the trial (Nivolumab) and standard of care (chemotherapy). Experimental cohorts were categorized into four pools, consisting of tissues from complete responders, partial responders, stable disease and progressive disease patients. We first analyzed tissues via whole-slide multiplex-immunohistochemistry (mIHC) using the Vectra Polaris spatial imaging platform. For this purpose we used 3 x 6 plex antibody panels, aimed at T-cell profiling, immune exhaustion and immuno-modulatory targets. We then expanded upon this work using an ultra-high plex antibody imaging panel of 50 or more antibodies with the aim at identifying additional spatial signatures in the different experimental conditions. The latter experiments were conducted with CODEX system, which readily provides whole-slide, single cell resolution imaging data from FFPE samples. Both datasets were for distinct spatial profiles in each experimental condition and compared to their clinical outcome to therapy via discriminant analyses. Identifying the benefit of treating patients with immune checkpoint inhibitor therapy prior to treatment will ensure better outcomes given that immunotherapies can only fight tumours that the immune system ‘sees’ and recognises as foreign and harmful. However, in tumour tissue, these biomarkers are highly variable and change dynamically. Therefore, there is growing consensus for the development of additional and more predictive biomarkers of response to ICI therapy. Spatial phenotyping of the immune landscape will reveal cell types and spatial signatures associated with outcomes to immunotherapy.
Citation Format: Arutha Kulasinghe, Ning Ma, James Monkman, Najiba Mammadova, Oliver Braubach, Ken O'Byrne. Profiling spatial signatures in the microenvironment of non-small cell lung carcinomas in immunotherapy responsive and resistant disease cohorts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1714.