LAUSR

182Background: The association between tumor mutational profiles and immune signatures has not been well-characterized. Methods: 306 melanoma samples were tested by NGS using a comprehensive cancer panel for mutational status and an immune response panel which interrogates the expression profile of 54 validated immune-related genes. The ranking of gene expression, mutational burden and 7 immune phenotypes was compared to a reference population. 38% cases were positive for activating BRAF mutations, 12% for RAS, and 6% for NF1. The remaining 44% were considered triple wild type. Principal component analysis (PCA) followed by hierarchical clustering was performed to determine association of BRAF/RAS/NF1 mutations and triple wild type with immune phenotypes, mutational burden and gene expression as measured by the NGS panels. Results: PCA showed that the first and second dimension explain 86% of the variation in the mutation profiles of the 306 melanomas. The first principal component highly correlated with ...