Uveal melanoma is a lethal cancer with a strong propensity to metastasize. Limited therapeutic options are available once the disease has disseminated. A strong predictor for metastasis is the loss of chromosome 3. Inactivating mutations in BAP1 encoding the BRCA1-associated protein 1 and located on chromosome 3p21.1, have been described in uveal melanoma and other types of cancer. In this study, we determined the prevalence of somatic BAP1 mutations and examined whether these mutations correlate with the functional expression of BAP1 in uveal melanoma tissue and with other clinical, histopathological and chromosomal parameters. We screened a cohort of 74 uveal melanomas for BAP1 mutations, using different deep sequencing methods. The frequency of BAP1 mutations in our study group was 47%. The expression of BAP1 protein was studied using immunohistochemistry. BAP1 staining was absent in 43% of the cases. BAP1 mutation status was strongly associated with BAP1 protein expression (Po0.001), loss of chromosome 3 (Po0.001), and other aggressive prognostic factors. Patients with a BAP1 mutation and absent BAP1 expression had an almost eightfold higher chance of developing metastases compared with those without these changes (P ¼ 0.002). We found a strong correlation between the immunohistochemical and sequencing data and therefore propose that, immunohistochemical screening for BAP1 should become routine in the histopathological work-up of uveal melanoma. Furthermore, our analysis indicates that loss of BAP1 may be particularly involved in the progression of uveal melanoma to an aggressive, metastatic phenotype.

Background/aims: Adult xanthogranulomatous disease involving the ocular tissues is rare and poorly understood. Adult onset xanthogranuloma (AOX), adult onset asthma and periocular xanthogranuloma (AAPOX), necrobiotic xanthogranuloma (NBX), and Erdheim-Chester disease (ECD) are the four syndromes within this disorder, which is diagnosed by characteristic histopathology. Experience with eight cases prompted a multi-institutional effort to study the histopathology, immunohistochemistry, clinical findings, and systemic associations in this disorder. Methods: 22 cases, including histopathological slides, were compiled. Published reports were identified by an English language Medline search and review of reference citations. Each case in this series and the literature was classified as one of four syndromes and then analysed for age onset, sex, skin xanthoma, orbital location, immune dysfunction, internal organ and bone lesions, treatment, and outcome. The histopathology in each of these cases was reviewed by two pathologists. Immunhistochemical stains (CD3, CD4, CD8, L26) were performed in 14 cases where unstained slides were available. Results: 137 cases were compiled. There was no sex or age difference between syndromes. AOX, AAPOX, NBX affect the anterior orbit, ECD tends to be diffuse and intraconal. Skin lesions are found in all the syndromes. Immune dysfunction was noted in all cases of AAPOX and NBX; 11% of NBX and all ECD patients had internal organ disease. Treatment included surgery, corticosteroids, other chemotherapeutic agents, radiotherapy, and combinations of these. No AOX or AAPOX deaths occurred; 66% of ECD patients died. All 22 cases had xanthoma cells; most had Touton giant cells. Lymphocytes were present in all cases and occurred as aggregates (mostly in AAPOX) or diffuse populations mixed with fibroblasts (mostly in ECD). Immunohistochemistry revealed the majority of these to be CD8+. Necrosis was most marked in NBX. Conclusion: Adult xanthogranuloma of the orbit is rare, making prospective evaluation or meta-analysis impossible. The best treatment is unknown but seems to be with multiagent chemotherapy guided by histopathological, immunohistochemical, and systemic findings.

A series of 256 consecutive cases of invasive primary conjunctival malignant melanomas was examined to identify clinical and histopathological prognostic factors. The follow up period varied between 0*3 and 45 9 years (mean 9 years, median 6*3 years). The 5 year survival rate was estimated at 82.9%, the 10 year survival rate at 69.3%. Multiple regression analysis with the Cox proportional hazards model was used to assess sex, age, and a number of baseline features of conjunctival malignant melanoma as possible prognostic factors influencing melanoma related mortality. In assessing each potential prognostic factor, the effects of all other factors were taken into account in the modelling process. Tumours in unfavourable locations -that is, those involving the palpebral conjunctiva, fornices, plica, caruncle, and lid margins, were associated with 2*2 times higher mortality compared with (epi)bulbar melanomas. Patients with mixed cell type tumours had about three times higher mortality compared with those with pure spindle cell melanomas, and histological evidence of lymphatic invasion by tumour cells was also a prognostic feature, carrying a fourfold increase in the death rate. Multifocal tumours were associated with a fivefold increase in mortality among those with tumours in favourable (epi)bulbar locations, but were not prognostic in patients with melanomas in unfavourable sites. The death rate was significantly higher in those with initial tumour thickness of more than 4 mm, but only among patients with unfavourably located melanomas. Sex, age, and clinical origin of the tumour (primary acquired melanosis, pre-existing naevus, or de novo) were not useful prognostic indicators in this study. (BrJ Ophthalmol 1994; 78: 252-259)

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In uveal melanoma, concurrent loss of the short arm of chromosome 1 and all of chromosome 3 is an independent predictor of decreased DFS.