Abstract 6774: The development of a spatial metabolic map of immunotherapy sensitive and resistant cutaneous skin carcinoma

Abstract Background: Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer and represents a major global health burden. Approximately 50% of cSCC patients develop primary resistance and 20% will develop secondary resistance to immune checkpoint inhibitors (ICI). There are limited biomarkers that reflect the tumor dynamics predictive of response to ICI therapy, and therefore we need to explore new biomarkers that can better understand the cSCC tumor microenvironment (TME). Methods: Our retrospective study profiled pre-treatment cutaneous skin cancer tissues from patients with immunotherapy sensitive and resistant diseases. In this exploratory study, we designed a high-dimensional > 50-plex antibody panel identifying cell lineages, activation states, and immune checkpoints. In addition, we deployed a combination of antibodies for a novel multiplexed metabolic readout, to enhance our in situ profiling beyond well-known TME targets. Whole-slide spatial phenotyping was conducted on the PhenoCycler-Fusion spatial biology platform. Highplex image analysis was performed using Phenoplex (Visiopharm), including tissue segmentation and cellular phenotyping. Here, we used a deep learning approach to discriminate tumor regions and margins based on their morphology. Spatial analyses including phenotypic composition, cell-to-cell localization, and cellular neighborhoods were performed and compared to clinicopathological findings and responses to ICI therapy. Results: We have profiled the TME of cSCC via ultrahigh-plex, single-cell spatial analyses of whole tissues. Our data have revealed unique cell phenotype compositions and metabolic states within the TME of different patient cohorts. Areas of metabolic activity were visualized and compartmentalized to determine spatial distributions of inherent sensitivity and resistance to ICI therapy. Additionally, a comparison of the phenotypic expression patterns between immunotherapy sensitive and resistant cohorts in the tumor, stromal and margin regions showed relevant differences in the immune content. Taken together, this high-dimensional imaging approach of the cSCC TME has revealed new tissue insights. Conclusion: There is a need to understand the contexture of the cSCC immune microenvironment. Here we identify distinct cellular phenotypic compositions and metabolic states in tissues from immune-competent and immunocompromised cSCC. We thereby confirm biological differences in tissue composition and cellular interactions between these tissues and provide putative new biomarkers for cSCC patient stratification. Citation Format: Niyati Jhaveri, Dmytro Klymyshyn, Bassem B. Cheikh, James Monkman, Dan Winkowski, James Mansfield, Subham Basu, Michael Prater, Nadine Nelson, Gabrielle Belz, Oliver Braubach, Arutha Kulasinghe. The development of a spatial metabolic map of immunotherapy sensitive and resistant cutaneous skin carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6774.