Specific human endogenous retroviruses predict metastatic potential In uveal melanoma.

Overview

Uveal melanoma (UM) represents a unique disease in that patients with primary UM are well stratified based on their risk of developing metastasis yet there are limited effective treatments once metastases occur. There is an urgent need to better understand the distinct molecular pathogenesis of UM and characteristics of patients at high risk for metastasis, to identify neo-antigenic targets which can be used in immunotherapy, and develop novel therapeutic strategies that may effectively target this lethal transition. An important and overlooked area of molecular pathogenesis and neoantigenic targets in UM come from human endogenous retroviruses (HERVs). We investigated the HERV expression landscape in primary UM and found that tumors stratified into four HERV-based subsets that provide clear delineation of risk outcome and support subtypes identified by other molecular indicators. Specific HERV loci are associated with the risk of uveal melanoma metastasis and may offer mechanistic insights into this process, including dysregulation of HERVs on chromosomes 3 and 8. A HERV signature comprised of 17 loci was sufficient to classify tumors according to subtype with >95% accuracy, including at least one intergenic HERV with coding potential (HERVE_Xp11.23) that could represent a new potential HERV E target for immunotherapy.