GNAQ Mutation in Uveal Melanomas is Associated with Histological Type: A Cytogenetic Study Comparing Clinicopathological Characteristics, Chromosomal Abnormalities, and GNA11 Mutations

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Although chromosomal abnormalities are established prognostic indicators, the role of GNAQ and GNA11 mutations remains unclear. In this retrospective cytogenetic study, we analyzed 67 enucleated UM samples. Chromosomal abnormalities (monosomy 3 and gains of chromosomes 6 and 8) and GNAQ/GNA11 mutations were examined using massively parallel sequencing and validated by Sanger sequencing. Associations with clinicopathological features and survival outcomes were statistically evaluated. GNAQ mutations were identified in 92.5% and GNA11 mutations in 58.2% of samples. A significant correlation was observed between GNAQ exon 5 mutations and histological tumor type, particularly a reduced frequency of spindle cell type B ( p = 0.041). No significant associations were found between GNAQ/GNA11 mutations and progression-free survival (PFS) or overall survival (OS). Monosomy 3 was detected in 49.3% of cases and remained the strongest prognostic factor. A subgroup of 14 patients harboring concurrent GNAQ and GNA11 exon 5 mutations exhibited a markedly lower risk of progression; however, this difference did not reach statistical significance. GNAQ and GNA11 mutations are highly prevalent in UM but show limited clinical and prognostic relevance, except for a potential association between GNAQ exon 5 mutation and histological subtype.