Monosomy 3 in uveal melanoma is associated with the presence of an inflammatory phenotype, consisting of a high HLA class I and II expression as well as an increased number of tumor-infiltrating macrophages. In a multivariate Cox regression analysis, the presence of monosomy 3 was one of the best prognostic markers of metastatic disease and survival, although the follow-up time was short.

VEGF-A expression by UM cells is mainly controlled by hypoxia and involves the HIF-1alpha pathway, thus indicating an important role for the tumor cell environment. Metastases led to increased serum VEGF-A levels, indicating that VEGF-A may be involved in the growth of metastases.

These data show that RASSF1a methylation is a common epigenetic event in uveal melanoma development, potentially of clinical relevance. The presence of a methylated RASSF1a promoter region might therefore serve as a tumor marker and as a possible target for therapeutic intervention.

Because of the very sensitive PAP technology, B-RAF mutations were found in cell lines and primary uveal melanomas, which suggests that they may occasionally play a role in the activation of the MAPK pathway in uveal melanoma and indicates a higher prevalence of B-RAF mutations in uveal melanoma than was reported earlier. However, the relative scarcity of the B-RAF mutation excludes an elemental role for this mutation in uveal melanoma.

Homozygosity, in combination with methylation, appears to be the mechanism targeting RASEF in uveal melanoma, and allelic imbalance at this locus supports a TSG role for RASEF.