Neoantigen-directed immune escape in lung cancer evolution

Abstract

The interplay between an evolving cancer and the dynamic immune-microenvironment remains unclear. Here, we analyze 258 regions from 88 early-stage untreated non-small cell lung cancers (NSCLCs) using RNAseq and pathology tumor infiltrating lymphocyte estimates. The immune-microenvironment was variable both between and within patients’ tumors. Diverse immune selection pressures were associated with different mechanisms of neoantigen presentation dysfunction restricted to distinct microenvironments. Sparsely infiltrated tumors exhibited evidence for historical immunoediting, with a waning of neoantigen-editing during tumor evolution, or copy number loss of historically clonal neoantigens. Immune-infiltrated tumor regions exhibited ongoing immunoediting, with either HLA LOH or depletion of expressed neoantigens. Promoter hypermethylation of genes harboring neoantigens was identified as an epigenetic mechanism of immunoediting. Our results suggest the immune-microenvironment exerts a strong selection pressure in early stage, untreated NSCLCs, producing multiple routes to immune evasion, which are clinically relevant, forecasting poor disease-free survival in multivariate analysis.