Genomic, prognostic, and cell-signaling advances in uveal melanoma

Uveal melanoma (UM) is the second-most common form of melanoma and the most common primary intraocular malignancy. Up to one-half of patients are at risk for fatal metastatic disease. The metastatic potential of an individual tumor can be accurately determined by analysis of a fine-needle aspirate with gene expression profiling assay that is available for routine clinical use through a commercial Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory. The test renders one of two results-class 1 (low metastatic risk) or class 2 (high metastatic risk)-and has been extensively validated in multiple centers. Until recently, the genetic mutations and signaling aberrations in UM were largely unknown. With the advent of new genomic sequencing technologies, however, the molecular landscape of UM is rapidly emerging. Mutations in the Gq alpha subunits GNAQ and GNA11 are mutually exclusive and represent early or initiating events that constitutively activate the MAPK pathway. Mutations in BRCA1-associated protein-1 (BAP1) and splicing factor 3B subunit 1 (SF3B1) also appear to be largely mutually exclusive, and they occur later in tumor progression. BAP1 mutations are strongly associated with metastasis, whereas SF3B1 mutations are associated with a more favorable outcome. BAP1 mutations can arise in the germ line, leading to a newly described BAP1 familial cancer syndrome. These discoveries have led to new clinical trials to assess several classes of compounds, including MEK, protein kinase C, and histone deacetylase inhibitors, in the adjuvant setting for high-risk patients identified as class 2, as well as in the setting of advanced disseminated disease.