Ian G. Rennie

Abnormalities of chromosomes 3 and 8 in posterior uveal melanoma correlate with prognosis

Posterior uveal melanomas have nonrandom alterations affecting chromosomes 3, 6, and 8. Loss of chromosome 3 in uveal melanoma has been shown to act as a predictor of disease‐free and overall survival. To confirm the significance of chromosome 3 loss and to extend the observations to include those of the associated alterations of chromosome 8, we have conducted a cytogenetic analysis on a series of 42 tumours from patients with primary uveal melanoma who were followed up for a median of 31 months (range = 8‐96 months). Abnormalities of chromosomes 3 and 8 were the commonest changes and were confirmed in 10 tumours using flourescence in situ hybridization. Monosomy of chromosome 3 was found in 21 (50%) of the tumours, and 23 (54%) tumours had additional copies of 8q. Alterations of chromosomes 3 and 8 were found occurring together in 19 (45%) of the tumours and were significantly associated with a ciliary body component (P < 0.0001). Prognostic indicators and changes of chromosomes 3 and 8 were analysed for correlation with patient survival. Of the chosen parameters, only ciliary body involvement (P = 0.003), monosomy of chromosome 3 (P = 0.0007), and additional copies of 8q (P = 0.003) correlated with reducted survival. Evaluation of the dosage effect of additional copies of chromosome arm 8q showed a significant association with reduced survival (P = 0.0001), which was also predictive of a decreased disease‐free interval (P = 0.01). Thus, the cytogenetic analysis of uveal melanoma may provide a valuable predictor of prognosis. Genes Chromosom. Cancer 19:22–28, 1997.

A critical appraisal of the prognostic and predictive factors for uveal malignant melanoma

The intraocular uveal tract comprises the iris, ciliary body and choroid. It contains a well-characterized population of melanocytes, from which uveal malignant melanoma takes origin. In adults uveal melanoma is the commonest primary intraocular malignant tumour. The estimated annual incidence ranges from 7.9 cases per million per year in the USA to 10 cases per million per year in Europe. Uveal melanoma is commoner in Caucasian males, with a median age of presentation of around 60 years. The incidence amongst whites is eight times greater than in blacks. The cause of uveal malignant melanoma is unknown, but several risk factors have been associated with disease development. Some personal characteristics, such as fair complexion, light irides, uveal naevi, dysplastic naevus syndrome, oculodermal and ocular melanocytosis and neurofibromatosis type 1 (NF1) have been associated with an increased risk of uveal melanoma. Furthermore, familial uveal melanoma is recognized and accounts for 0.6% of all uveal melanoma cases, with a proposed autosomal dominant mode of inheritance. The mortality due to uveal melanoma has remained relatively unchanged, despite earlier detection and consequently smaller primary tumour burdens. Metastasis occurs via the blood, classically to the liver, and around 1% of patients have clinically demonstrable liver metastases at presentation. Ultimately, 40% of patients will go on to develop liver metastases, which occur, on average, 10 years after diagnosis and treatment of the primary neoplasm. This probably reflects subclinical hepatic metastasis at the time of the initial diagnosis. Once liver metastases are clinically apparent, the outlook is poor (survival on average 5–9 months).

Effect of TNF, IL-1, and IL-6 on the proliferation of human Tenon's capsule fibroblasts in tissue culture.

Trabeculectomy is a commonly performed procedure for primary open angle glaucoma and is successful in the majority of cases. However, certain factors including aphakia, previous surgery, secondary glaucomas, ethnic origin, and the long term use of topical antiglaucoma medications may be associated with a reduced success rate. The mechanism (or mechanisms) which influence clinical outcome following trabeculectomy remain elusive. Alterations in the composition of the conjunctiva or aqueous humour may be partly responsible for this effect, and this could be mediated by cytokines. In this study we found that tumour necrosis factor (TNF), and interleukin 1 (IL-1) were capable of stimulating the proliferation of Tenons capsule fibroblasts in tissue culture. Interleukin 6 (IL-6) did not appear to have any effect. The relevance of this to wound healing following trabeculectomy is discussed.

Clinically Important Ocular Reactions to Systemic Drug Therapy

SummaryMany systemically administered drugs produce ocular adverse effects. Fortunately, relatively few are capable of causing significant, irreversible visual impairment. It is the responsibility of every clinician when prescribing systemic therapeutic agents to be aware of potential adverse ocular reactions, to appreciate their significance, and to inform the patient of the potential risks of treatment. In instances where serious adverse reactions relate to the cumulative effects of prolonged treatment, it is the responsibility of the prescribing physician to institute appropriate methods of visual screening. In this respect, it is most important to obtain the necessary individual baseline measurements before treatment is commenced.Chloroquine retinopathy is probably the most feared of all adverse ocular reactions to systemic drug therapy. However, it occurs only rarely if the daily dosage of chloroquine does not exceed 250mg. Regular screening using automated perimetry is mandatory if prolonged therapy is contemplated.Amiodarone almost inevitably produces corneal deposits. These rarely produce symptoms, and resolve upon withdrawal of the drug. Optic neuropathy has recently been described with amiodarone.Systemic anticoagulant therapy may be associated with intraocular haemmorhage in patients with pre-existing disciform macular degeneration, and such agents should be used with caution in affected individuals.Systemic corticosteroids produce posterior subcapsular cataracts in susceptible individuals which may profoundly affect visual acuity. Although elevated intraocular pressure may also result from systemic therapy, the relationship between the pressure rise and development of glaucomatous changes remains unclear.Ethambutol may produce optic neuropathy if the daily dosage exceeds 15 mg/kg. The changes are usually reversible within a few weeks of stopping treatment.High doses of tamoxifen may produce a maculopathy with loss of visual acuity, if given for prolonged periods. The risk must be weighed against the benefits of treatment.Patients receiving more than 800 mg/day of thioridazine have developed retinopathy, which is usually reversible if detected early enough. Tricyclic antidepressants and other agents with anticholinergic properties may cause disturbances of accommodation and pupillary dilatation. The latter may rarely precipitate acute angle closure glaucoma in susceptible individuals.

C-myc oncogene expression in ocular melanomas

We have investigated the expression of c-myc in 24 ocular melanomas by immunohistochemistry, using two monoclonal antibodies raised against a midsequence portion of the c-myc product (6E10) and against the C-terminus (9E10). The results were compared with other putative prognostic factors, including tumour size, cell type, proliferation index (determined by flow cytometry), and ploidy, as well as immunohistochemical staining for HMB-45 and S-100 antigens. Staining, often focal, for c-myc was found in both the nucleus and the cytoplasm of a proportion of the cells in most tumours studied. Total cell staining for myc protein correlated with proliferative index in diploid tumours; seven out of nine aneuploid and mixed aneuploid/diploid cells showed strong staining in at least one cellular compartment. A positive correlation with myc expression was also found for HMB-45 staining, but not for cell type or staining for S-100. The results support the hypothesis that myc protein is involved in cellular proliferation in uveal melanomas and indicate that immunohistochemistry for myc antigen may be a useful prognostic marker in these tumours.

Cytogenetics of Iris Melanomas: Disparity with Other Uveal Tract Melanomas

The chromosomal alterations of iris melanomas are poorly characterized, only one report has been detailed. Cytogenetic analysis was performed on the tumors and heparinized blood samples of three patients with iris melanomas; in one case a primary tumor and its related seedling were examined. On analysis of lymphocytes, two of the patients were found to experience a low level fragility of chromosome 9, in the region of a cutaneous melanoma susceptibility gene. All iris melanoma lesions were karyotyped. Clonal abnormalities of chromosomes 3, 5, 6, 7, 8, 9, 12, 15, 17, 18, 19, and Y were found, and in one case a large number of marker chromosomes were observed. No specific chromosomal change was common to the iris melanomas, but two cases had different abnormalities of chromosomes 5 and 18. Variations between the primary tumor and its related seedling were the acquisition of an additional chromosome 15, and a polyploid form of the cell line in the seedling. This study suggests that the most common chromosomal changes of posterior uveal melanomas are less frequent in iris melanomas. Iris melanomas also appear to experience relatively high levels of chromosomal alterations, including the formation of marker chromosomes, which is perhaps reminiscent of cutaneous melanoma.

Fluorescence in situ hybridisation (FISH) in histologically challenging conjunctival melanocytic lesions

Background Even in experienced hands, the classification of some melanocytic lesions of the conjunctiva remains challenging. In skin pathology, the recent application of fluorescence in situ hybridisation (FISH) has been demonstrated to be of use for the analysis and diagnosis of ambiguous melanocytic neoplasms of the skin. This study set out to evaluate this method on seven prospective conjunctival cases that were histologically equivocal. Methods 18 unequivocal retrospective melanocytic controls were exposed to FISH. Commercially available probes assessing copy numbers of RREB1 (6p25), MYB (6q23) and CCND1 (11q13) genes compared with CEP6 (a chromosome six centromeric reference point) were used. After control verification, seven prospective, equivocal cases were identified and exposed to FISH. Results There was complete correlation between FISH result and the control section histopathology report. Control cases of melanoma cases were all positive for FISH and control benign lesions were negative. Of the seven equivocal cases, five were positive and classed as invasive melanoma or melanoma-in situ, one was negative and one tetraploid, classed as negative (these last two cases were classed as naevi with careful clinical observation). Conclusions FISH is very useful in classifying equivocal conjunctival melanocytic lesions, especially those with atypical junctional activity and naevoid melanocytic proliferations of the conjunctiva.

Ocular surface squamous neoplasia: analysis of 78 cases from a UK ocular oncology centre

Background/aims Ocular surface squamous neoplasia (OSSN) is a spectrum of disease, on which few large series have been published, none in particular, from the UK. The purpose of this study is to describe experience of this condition from a UK national ocular oncology centre, including statistical analysis to elucidate factors significant in recurrence. Methods Retrospective review of case notes, clinical photographs and histopathology reports. Results 78 cases were included, of which 10 (12.8%) recurred during the follow-up time (mean 37 months). The 1-year recurrence rate was 10.9%, and 5-year recurrence rate was 18.5% using Kaplan-Meier analysis, with a mean time to recurrence of 9.5 months. Significant factors in recurrence were tumour size and first treatment given. Grade of OSSN, including presence of invasive disease and positive biopsy margins were not found to be statistically significant in recurrence. Conclusions OSSN in an uncommon disease in the UK population. However, when managed appropriately in a specialist centre, it is associated with good outcomes, even in recurrence situations.

Immunohistochemical and molecular pathology of ocular uveal melanocytoma: evidence for somatic GNAQ mutations

Objective Intraocular melanocytoma is a rare naevus variant that can be located at the optic disc or within the uvea, and belongs to the group of non-epithelial-associated melanocytic lesions. We wanted to gain an understanding of the role of GNAQ, GNA11 and BRAF V600E in the pathogenesis of uveal melanocytoma and in cases of transformation to uveal melanoma and also to perform a differential immunohistochemical study comparing melanocytoma with uveal melanoma. Methods and results Two patients were identified with melanocytoma, one of which had transformed to melanoma. In the latter case, the melanocytoma exhibited an immunophenotype that featured nuclear p27 and no HMB45 staining, with very low Cyclin D1 expression compared with the melanoma that featured little nuclear but more cytoplasmic p27 positivity, much higher Cyclin D1 expression and HMB45 positivity. The melanocytomas were negative for CD68 allowing distinction from melanophages. Both melanocytomas and the melanoma harboured mutations in GNAQ, with no mutations of GNA11 or BRAF V600E. Conclusions GNAQ mutations are present in uveal melanocytomas and in a case of transformation to melanoma, implicating GNAQ-dependent mitogen activation signals, in the pathogenesis of uveal melanocytoma. This assists in explaining why a proportion of uveal melanocytoma can transform to uveal melanoma, known to harbour high-frequency GNAQ mutations at exon 5, codon 209.

The in vivo modulatory effects of an anterior-chamber microenvironment on uveal melanoma

Background: Primary melanoma of the iris, for reasons unknown has a lower metastatic rate compared with primary ciliary-body melanoma. Six histology cases of ciliary-body melanoma were identified that had spread onto the iris surface and into the stroma, representing a change in tumour microenvironment from aqueous humour non-exposure (ciliary-body component) to aqueous humour exposure (iris surface component). This provided an ideal paradigm for investigating the effects of different environments on melanoma. Method: Conventional light microscopy was performed on stained paraffin sections of the identified cases, followed by immunohistochemistry to cell cycle proteins p27 and Cyclin D1. Fluorescence in situ hybridisation (FISH) analysis was conducted on the paraffin sections for changes of chromosomes 3 and 8, associated with poor uveal melanoma prognosis. Results: Iris surface melanoma cells were smaller compared with the adjacent deeper iris stromal melanoma cells and with those in the ciliary body. Fewer iris surface melanoma cells expressed Cyclin D1 protein, but more expressed p27 protein, compared with the larger iris stromal melanoma cells (paired Wilcoxon signed ranks test: Cyclin D1 p = 0.028; p27 p = 0.046) and with the ciliary-body melanoma cells (paired Wilcoxon signed ranks test: Cyclin D1 p = 0.028; p27 p = 0.028). With FISH, chromosome 3 and 8 alterations were less common among the iris surface melanoma cells than the deeper iris stromal melanoma cells and the ciliary-body melanoma cells, which were consistently characterised by a relative genetic imbalance for chromosomes 3 and 8. Conclusions: These data suggest that there are tumour-modulatory factors within the anterior chamber environment that probably select populations of ciliary-body melanoma cells, with a less aggressive, better-differentiated status. Furthermore, it may help explain why iris melanomas generally have a less aggressive course than ciliary-body and choroidal melanomas.