1283 In vivo phenotyping of the tumor immune microenvironment to predict melanoma outcomes

Tumor outcomes (progression, response to immunotherapies) are influenced by tumor-intrinsic and the tumor-immune microenvironment (TiME) factors. To overcome existing limitations of phenotyping tumors using single-time, single-siteex vivo biopsies in predicting tumor behavior, we propose an integrated dynamic approach for TiME combining inflammation, vasculature/ angiogenesis features through high-resolution reflectance confocal microscopy (RCM) patients. Melanoma patients (n=35) were imaged characterize density spatial distribution tumor, vasculature/angiogenesis leukocyte trafficking. Unsupervised clustering (hierarchical analysis, HCA principal component PCA) was performed on manually evaluated derive phenotypes, correlated with immune cells (T-cells, B-cells) tertiary lymphoid structures (TLS), topical toll-like receptor agonist imiquimod. We demonstrate three main InflamHIGHVascHIGH, InflamHIGHVascLOW InflamLOWVascHIGH PCA (top contributors PC1: inflammation while PC2: vasculature). Highest T-cell B-cell infiltration (p<0.01), TLS presence (ns) seen InflamHIGH phenotype. Overall, lower lichenoid number vessels found be hallmarks non-responders. Our preliminary results support unique phenotypes melanoma that correlate underlying states, TLRA immunotherapy.