Insights into genetic alterations of liver metastases from uveal melanoma.

The liver is the organ usually affected by metastatic uveal melanoma (MUM). Current treatments are almost always ineffective and mortality remains high. In this study, copy number variations (CNVs) were identified in 12 metastatic and five matched primary UMs (PUMs). Our data revealed a wide spectrum of genetic alterations in MUM. Most common were amplifications of chromosome (chr.) 8q; alterations on chr. 3 included monosomy, isodisomy, and large regions of homozygosity (ROH). Genomic profiles of PUM-MUM pairs varied in their degree of similarity and complexity. However, within the pairs, 135 genes were consistently altered. Protein expression of C-MYC and BAP1 was examined by immunohistochemistry (IHC); a positive association between IHC and CNVs was seen for C-MYC. This comprehensive catalogue of CNVs associated with MUM should facilitate the identification of key alterations that drive tumor growth. This would have the potential to select urgently needed novel, targeted, therapeutic regimens.