BAP1 Immunoreactivity Correlates with Gene Expression Class in Uveal Melanoma

Area of Science:

• Ophthalmology
• Oncology
• Molecular Pathology

Background:

• Uveal melanoma (UM) is the most common primary adult intraocular malignancy.
• Accurate prediction of UM metastasis risk is crucial for patient management.
• BRCA1-associated protein-1 (BAP1) immunohistochemistry (IHC) and gene expression profiling (GEP) are prognostic tools for UM.

Purpose of the Study:

• To compare the prognostic significance of BAP1-IHC staining patterns and GEP in predicting UM metastasis risk.
• To correlate BAP1 expression with GEP classifications in UM.
• To evaluate the accuracy of BAP1-IHC and GEP in identifying patients at high risk for metastasis.

Main Methods:

• Retrospective chart review and prospective follow-up of 30 primary UM patients undergoing enucleation (2008-2018).
• Collection of clinical history, histopathology, GEP classification, and BAP1-IHC data.
• Statistical analysis to correlate BAP1 expression patterns and GEP with metastasis development.

Main Results:

• Low nuclear BAP1 expression was observed in 68% of UM cases that developed metastasis, versus 9% with high nuclear expression.
• Gene expression profiling (GEP) class 2 tumors showed low nuclear BAP1 expression.
• Nuclear BAP1-IHC and GEP demonstrated equal accuracy (77%) in predicting metastasis, outperforming cytoplasmic BAP1-IHC (57%).

Conclusions:

• Low nuclear BAP1-IHC is a strong indicator of GEP class 2 in UM.
• Nuclear BAP1-IHC is as accurate as GEP in predicting UM metastasis.
• BAP1-IHC serves as a reliable and accessible prognostic marker for uveal melanoma metastasis risk.