Clinicopathological Characteristics and BAP1 Expression in an Enucleation-Based Uveal Melanoma Cohort: A Single-Center Croatian Experience with Long-Term Follow-Up.
Most enucleated uveal melanomas showed loss of BAP1 protein expression.
Clinicopathological Characteristics and BAP1 Expression in an Enucleation-Based Uveal Melanoma Cohort: A Single-Center Croatian Experience with Long-Term Follow-Up.
Loss of nuclear BAP1 (BRCA1-associated protein 1) expression is a well-established adverse prognostic marker in uveal melanoma (uveal melanoma).
This descriptive study aimed to evaluate BAP1 immunohistochemical expression in a Croatian enucleation-based uveal melanoma cohort, characterize its associations with clinicopathological parameters, and contextualize the findings within the published literature.
Formalin-fixed, paraffin-embedded tumor tissue from 58 consecutive patients with primary choroidal and ciliary body melanoma treated with enucleation at University Hospital Centre Zagreb (2006-2016) was analyzed immunohistochemically for BAP1 nuclear expression.
Five-year and 10-year overall survival rates were 72.4% and 51.7%, respectively, with a median overall survival of 14.5 years.
BAP1 loss was associated with longer disease-free survival (log-rank p = 0.020); however, this finding likely reflects a statistical artifact attributable to the extremely small BAP1-retained group ( n = 5) harboring concurrent adverse features and should not be interpreted biologically.
The exceptionally high prevalence of BAP1 loss reflects the selection bias inherent in enucleation-based cohorts, which are enriched for large, molecularly high-risk tumors.
This study provides the first comprehensive BAP1 immunohistochemical data from Croatia, contributing to the growing evidence that enucleation cohorts represent a distinct, biologically high-risk subgroup in which BAP1 immunohistochemistry offers limited discriminatory value.
The extended follow-up of 11.2 years confirms the prolonged natural history of uveal melanoma.