[Uveal Melanoma Cell Under Oxidative Stress - Influence of VEGF and VEGF-Inhibitors]. / Uveale Melanomzellen unter oxidativem Stress ­ Einfluss von VEGF und VEGF-Inhibitoren.

BACKGROUND: The role of oxidative stress in cancer is complex. While the pathological alterations induced by oxidative stress may be involved in the induction of tumours, in the late stages of tumour development, it can facilitate the loss of tumour cells and might even prevent metastasis. Tumour cells show metabolic alterations, often inducing an increased production of reactive oxygen species, which makes these cells particularly vulnerable to additional oxidative stress. This is an important mode of action in the use of many chemotherapeutics and in the application of ionizing radiation. Uveal melanoma is the most frequent primary tumour in the adult eye. For metastasis of this tumour, which affects about 50 % of the patients, no appropriate treatment is currently available. However, the primary tumour can efficiently be treated with ionizing radiation. A frequent side effect of this treatment is radiation retinopathy, which is treated with vascular endothelial growth factor (VEGF) antagonists. A therapy of the primary tumour with VEGF antagonists is under discussion. So far, little data is available on this subject, however, a paradoxical worsening of the situation has been found in a mouse model of uveal melanoma treated with bevacizumab. METHODS: We have investigated the effect of VEGF and of the VEGF-antagonist bevacizumab on the survival of five different melanoma cell lines under oxidative stress treatment with hydrogen peroxide. In addition, we investigated the expression of relevant proteins and the effect of bevacizumab on the proliferation of the cells as well as its effect on the angiogenic behaviour of endothelial cells, co-cultured with uveal melanoma cells. RESULTS: Our study showed that not only VEGF but also, paradoxically, the VEGF-antagonist bevacizumab is able to protect uveal melanoma cells from oxidative stress-induced cell death. Bevacizumab did not influence the proliferation of the cells and showed only limited effectiveness to reduce angiogenic structures. CONCLUSION: Considering that oxidative stress is the mode of action for ionizing radiation to induce cell death, a protective effect of bevacizumab on uveal melanoma cells against oxidative stress is worrisome and argues against the use of VEGF in uveal melanoma.

Altered Nuclear Expression of the Deubiquitylase BAP1 Cannot be Used as a Prognostic Marker for Canine Melanoma.

BRCA1-associated protein-1 (BAP1) is a nuclear localized deubiquitylating enzyme that belongs to the ubiquitin c-terminal hydrolase subfamily. The encoded protein is highly homologous between man and dogs, suggesting a functional significance preserved by evolution. BAP1 has multiple properties, including tumour suppressor activity. Loss of BAP1 function is implicated in the oncogenesis of several types of cancers including uveal, mucosal and some cutaneous melanomas in humans, as well as in mesothelioma. In this study we investigate the significance of BAP1 in canine melanoma. Nuclear BAP1 protein was detected in five canine oral melanoma cell lines using an antibody commonly used for analysis of human tissues. BAP1 loss of function mutations often lead to loss of nuclear BAP1 (nBAP1) expression in humans; this is associated with a poorer prognosis in uveal and mucosal melanoma. Therefore, as a prelude to a study evaluating the prognostic significance of nBAP1 expression in dogs, immunohistochemistry (IHC) was used to assess cases of canine melanoma for nBAP1 expression. In 89 cases where tumour cells were identified by melan-A labelling, 100% of tumour cells were positive for nBAP1 expression, including eight uveal tract and 29 oral mucosal melanomas. This finding indicates that BAP1 IHC cannot be used as a prognostic marker in canine uveal and mucosal melanoma. Moreover, this observation suggests that either BAP1 has a different functional significance in canine melanoma or that loss of BAP1 function is achieved by a different route. This is a novel finding that warrants further investigation to determine the comparative biological relevance.

Electrochemotherapy with bleomycin and cisplatin enhances cytotoxicity in primary and metastatic uveal melanoma cell lines in vitro.

Electrochemotherapy (ECT) enhances responsiveness to cytotoxic drugs in numerous cell lines in vitro. Clinically ECT is widely applied for skin tumor ablation and has shown efficacy in treating non-resectable colorectal liver metastases. There is limited experience of ECT for ocular tumor therapy. We investigated the cytotoxic effect of bleomycin and cisplatin in combination with electroporation on chemoresistant human uveal melanoma (UM) cell lines in vitro. Four UM cell lines (Mel 270, 92-1, OMM-1, OMM-2.5) were treated with electroporation (pulse amplitude 300-1000 V/cm, 8-80 pulses, 100 µs, 5 Hz) and increasing concentrations of bleomycin and cisplatin (0-7.5 µg/ml). Cell survival was analyzed by MTT viability assay after 36 hours. UM cell lines were resistant to both bleomycin and cisplatin. In combination with electro- poration, the effects of bleomycin and cisplatin were increased 8-70 fold and 3-15 fold, respectively, in all UM cell lines. At the lowest concentration of bleomycin tested (1 µg/ml), viability was maximally reduced in all UM cell lines by ≥69% with electroporation conditions of 750 V/cm and 20 pulses. All UM cell lines were more resistant to cisplatin; however, electro- poration of 1000 V/cm and 8 pulses resulted in similar reductions in cell viability of 92-1, Mel270 with 2.5 µg/ml cisplatin, OMM2-5 cells with 5 µg/ml cisplatin and OMM1 cells with 1 µg/ml cisplatin. In vitro ECT with bleomycin or cisplatin is more effective than the highest concentration of the antineoplastic drug or electroporation alone, opening new perspectives in primary and metastatic UM treatment.

[Primary vitreoretinal lymphoma]. / Primäre vitreoretinale Lymphome.

Primary vitreoretinal lymphoma (PVRL) is the most common intraocular lymphoma. It is a high grade malignant B­cell lymphoma, which is thought to arise in the retina. It often infiltrates the central nervous system (CNS) and is therefore associated with a poor prognosis. The PVRL must be differentiated from other forms of intraocular lymphoma, such as the low-grade B­cell lymphoma that rarely arises in the choroid. The choroidal lymphomas do not spread to the brain, they can be treated with low-dose external beam radiotherapy and the patients have a good prognosis. Since PVRL is a relatively rare tumor, there is little information with respect to its true incidence, to any geographical or ethnic variability and to the main risk factors apart from an association with immunosuppression, as a result of HIV or Epstein-Barr virus infections. The treatment of PVRL is very variable between oncology centres and is also dependent on the unilaterality or bilaterality of disease and whether there is any concomitant CNS involvement. Further studies and research projects in this field are necessary in order to diagnose PVRL at an early stage and to develop new targeted individualized treatment.

[Ocular melanomas : An update]. / Okuläre Melanome : Ein "Update".

Melanoma is the most common type of primary cancer to affect the adult eye. Approximately 95% of ocular melanomas are intraocular and arise from the uvea (i. e. iris, ciliary body, and choroid), while the remaining 5% are located in the conjunctiva. Although both uveal and conjunctival melanomas are thought to derive from malignantly transformed melanocytes, uveal melanoma is clinically and biologically distinct from conjunctival melanoma, and indeed from its more common cutaneous counterpart. Intense efforts have been recently made to understand the molecular biology involved in the development of ocular melanomas, and in their progression. Molecular advances, particularly for uveal melanoma, have enhanced prognostication and the identification of rational therapeutic targets for disseminated disease. In this review, recent advances in the molecular characterisation of both uveal and conjunctival melanomas are discussed, and how these may be used to develop personalised therapeutic strategies.

[Malignant lymphomas of the eye]. / Maligne Lymphome des Auges.

The eye and the ocular adnexae are rare sites for malignant non-Hodgkin lymphoma (NHL). Based on their anatomical location, intraocular lymphomas must be discerned from NHL of adnexal structures including conjunctiva, lacrimal gland, and orbit. Whereas the latter group mostly consists of indolent extranodal marginal zone B­cell lymphomas of mucosa-associated lymphoid tissue (MALT) type or secondary manifestations of systemic NHL, most primary intraocular lymphomas are classified as diffuse large B­cell lymphomas (DLBCL) and are considered a variant of primary DLBCL of the central nervous system. The most common form is primary vitreoretinal lymphoma (PVRL), which presents with nonspecific symptoms and is difficult to discern from uveitis. Diagnosis of PVRL is usually made by cytological, immunocytochemical, and molecular analysis of vitreous aspirates. Degenerative changes, limited material, and the occurrence of pseudoclonality in the molecular analysis of B­cell clonality can hamper diagnostic assessment. Novel techniques such as detection of MYD88 mutations common in PVRL can increase diagnostic sensitivity. Close cooperation with clinical colleagues and rapid specimen processing are fundamental for successful diagnosis.

The epidemiology, clinical characteristics, histopathology and management of juvenile- and adult-onset corneoscleral limbus xanthogranuloma.

PURPOSE: Adult-onset xanthogranuloma (AOX) of the corneoscleral limbus is a rare inflammatory condition of unknown aetiology. Similar to limbal juvenile xanthogranuloma (JXG), it presents as a growing mass at the corneoscleral junction. Limbal AOX and JXG can lead to sight-threatening complications if not managed in a timely manner. This systematic review summarises the main clinical and histopathological features of limbal AOX/JXG and discusses the management of this uncommon disease. METHODS: We performed a literature search in the MEDLINE database for all historical entries, using the search terms "limbus", "limbal" and "xanthogranuloma", and retrieved all articles reporting on limbal xanthogranuloma. After refining the search to articles relevant to limbal AOX, we were able to identify ten adult cases of limbal AOX and compare those with all reported cases of limbal JXG. RESULTS: Clinically, AOX usually presents as an isolated smooth, yellowish, dome-shaped nodule at the corneoscleral junction, similar to an ocular presentation of JXG, with which it also shares similar histopathological features. CONCLUSION: Limbal JXG and AOX may represent the same disease entity. Diagnosis relies on the clinical presentation, pathology and immunohistochemical profile. Spontaneous regression is unlikely, and thus prompt surgical intervention should be considered to prevent sight-threatening complications. Xanthogranuloma should be included in the differential diagnosis of corneoscleral limbal masses in patients of all age groups.

[Unusual masquerade of an ocular carcinoma metastasis]. / Untypische Masquerade einer okulären Karzinommetastase.

BACKGROUND: Idiopathic and therapy resistant uveitis especially of unclear origin, is a diagnostic challenge for ophthalmologists. Metastases to the anterior chamber or vitreous body can occasionally mimic the clinical picture of uveitis, a variant on the usual lymphomatous masquerade syndrome. The underlying pathological pathways leading to the metastatic spread of tumor cells within the fluid compartments of the eye remain unclear. CASE REPORT: We present an unusual case of vitreous metastases to the right eye of a patient in whom an underlying primary malignancy was unknown. After recurrent episodes of cortisone-refractive panuveitis with pseudohypopyon, a diagnostic vitreous biopsy was performed. Cytopathological examination of the vitreous sample revealed carcinoma cells with an immune profile suggestive of lung cancer metastasis. Subsequent staging investigations revealed a primary lung adenocarcinoma as well as cerebral, adrenal and osseous metastases. THERAPY: Due to the extent of dissemination of this non-small cell lung cancer (NSCLC), only palliative treatment including external beam irradiation and systemic chemotherapy was possible to reduce pain and to maintain vision as well as an attempt at systemic control of the disease.

Conjunctival squamous cell neoplasia: the Liverpool Ocular Oncology Centre experience.

PURPOSE: To report the outcome of patients with conjunctival squamous cell neoplasia (CSCN)--including conjunctival squamous cell carcinoma (SCC), conjunctival squamous intraepithelial neoplasia (C-SIN) and carcinoma in situ (CIS)-treated at the Liverpool Ocular Oncology Centre (LOOC). METHODS: Patients treated between January 1993 and September 2011 were identified and categorised as having 'primary' or 'salvage' treatment, according to whether they had undergone a surgical procedure before referral to our centre. Invasive SCC was treated by excision with adjunctive ruthenium plaque radiotherapy. C-SIN or CIS was treated with topical 5-fluorouracil (5-FU), and in a few cases, cryotherapy. RESULTS: Primary treatment was administered to 20 patients (16 males, four females). Mean age was 62 years (range, 33-85). Histological examination revealed C-SIN/CIS in ten patients and invasive SCC in nine. Median follow-up was 69 months (range, 34-168). Three patients required further topical chemotherapy for persistent/recurrent C-SIN. Salvage therapy was administered to 21 patients (15 males, six females). Mean age was 63 years (range, 26-82). Histology showed C-SIN/CIS in 11 patients and invasive SCC in ten. Median follow-up was 54.5 months (range, 36-120). At the close of this audit, there was no recurrence of invasive or metastatic disease in either the primary or salvage groups. CONCLUSIONS: Our established protocol for treatment of CSCN has proven successful in local tumour control, and avoids ocular complications. We advocate adjunctive radiotherapy in patients with invasive SCC and chemotherapy in C-SIN/CIS. For improved patient outcome, prompt referral to a specialist centre is encouraged.

Lack of BAP1 protein expression in uveal melanoma is associated with increased metastatic risk and has utility in routine prognostic testing.

BACKGROUND: The absence of BRCA1-associated protein 1 (BAP1) expression in uveal melanoma (UM) is associated with metastatic progression and reduced survival. In this study, we examine nuclear BAP1 (nBAP1) protein expression in primary UMs (PUMs) that show both 'typical' and 'atypical' clinical courses according to their chromosome 3 status, and secondary hepatic metastatic UM (MUM), correlating the results with histological, clinical and survival data. METHODS: Nuclear BAP1 expression was immunohistochemically assessed in tissue microarrays (TMAs) of: (a) 68 PUM patients, who had been treated surgically; and (b) 13 MUM patients, with 5 cases being paired with primary tumour tissue. All cases were fully annotated. The percentage of tumour cell nuclei staining positively for BAP1 was scored by independent observers. RESULTS: Nuclear BAP1 protein expression was absent in 35 out of 68 (51%) PUM patients, correlating strongly with poor prognostic clinicopathological and genetic parameters and reduced survival (Log rank, P<0.001). Lack of nBAP1 expression importantly identified a subset of 'atypical' PUM patients with disomy of chromosome 3 but with unexpected metastatic relapse. Nuclear BAP1 expression was absent in 10 out of 13 (77%) MUM and expression was concordant in all paired PUM and MUM patients. CONCLUSIONS: Absent nBAP1 protein expression is an independent survival predictor for UM patients, easily examined using immunohistochemistry.

Targeting SRPK1 to control VEGF-mediated tumour angiogenesis in metastatic melanoma.

BACKGROUND: Current therapies for metastatic melanoma are targeted either at cancer mutations driving growth (e.g., vemurafenib) or immune-based therapies (e.g., ipilimumab). Tumour progression also requires angiogenesis, which is regulated by VEGF-A, itself alternatively spliced to form two families of isoforms, pro- and anti-angiogenic. Metastatic melanoma is associated with a splicing switch to pro-angiogenic VEGF-A, previously shown to be regulated by SRSF1 phosphorylation by SRPK1. Here, we show a novel approach to preventing angiogenesis-targeting splicing factor kinases that are highly expressed in melanomas. METHODS: We used RT-PCR, western blotting and immunohistochemistry to investigate SRPK1, SRSF1 and VEGF expression in tumour cells, and in vivo xenograft assays to investigate SRPK1 knockdown and inhibition in vivo. RESULTS: In both uveal and cutaneous melanoma cell lines, SRPK1 was highly expressed, and inhibition of SRPK1 by knockdown or with pharmacological inhibitors reduced pro-angiogenic VEGF expression maintaining the production of anti-angiogenic VEGF isoforms. Both pharmacological SRPK1 inhibitors and SRPK1 knockdown reduced growth of human melanomas in vivo, but neither affected cell proliferation in vitro. CONCLUSIONS: These results suggest that selective blocking of pro-angiogenic isoforms by inhibiting splice-site selection with SRPK1 inhibitors reduces melanoma growth. SRPK1 inhibitors may be used as therapeutic agents.

The Liverpool uveal melanoma liver metastases pathway: outcome following liver resection.

AIM: To determine the outcome of patients that underwent liver resection for metastases from uveal melanoma. METHODS: Over a 9-year period, patients referred with uveal melanoma metastases were included. Following treatment of primary uveal melanoma, high-risk patients were offered to be enrolled into a 6-monthly non-contrast liver magnetic resonance imaging (MRI) surveillance. Following detection of liver metastases, patients were staged with a contrast-enhanced (Primovist(®)) liver MRI, computer tomography (CT) of the thorax and staging laparoscopy. RESULTS: 155 patients were referred with uveal melanoma liver metastases, of which 17 (11.0%) patients had liver resection and one patient was treated with percutaneous radio-frequency ablation. The majority of patients undergoing liver resection were treated with multiple metastectomies (n = 8) and three patients had major liver resections. The overall median survival for patients treated with surgery/ablation was 27 (14-90) months, and this was significantly better compared to patients treated palliatively [median = 8(1-30) months, P < 0.001]. Following surgery, 11 patients had recurrent disease [median = 13(6-36) months]. Patients who had undergone a major liver resection had a significantly poorer disease-free survival (P = 0.037). CONCLUSIONS: Patients who can undergo surgical resection for metastatic uveal melanoma have a more favorable survival compared to those who do not.

Molecular pathology of lymphoma.

Ocular lymphomas can be divided into intraocular lymphomas and ocular adnexal lymphomas. The vitreoretinal lymphoma-usually a diffuse large B-cell lymphoma (DLBCL) of high-grade malignancy-is the most common lymphoid malignancy arising in the eye, while the extranodal marginal zone B-cell lymphoma (EMZL), an indolent often recurrent tumour, occurs most frequently in the ocular adnexal tissue. The two lymphoma subtypes differ significantly in their clinical presentation, subsequent course and outcome as well as in their underlying morphological, immunophenotypical and genetic features. The molecular processes involved in DLBCL and EMZL development are complex, and include chromosomal translocations, mutations caused by aberrant somatic hypermutation, sporadic somatic mutations, and copy number alterations, characterized by deletions and amplifications. These lead to alterations in particular signalling pathways, which in turn activate transcription factors, such as nuclear factor NF-κB. This review provides an overview of the histological features of DLBCL and EMZL, and discusses the current insights into the molecular mechanisms underlying the development of these tumours, when they occur systemically and particularly when they arise in ocular tissues.

Molecular pathology of uveal melanoma.

Like other cancers, uveal melanomas (UM) are characterised by an uncontrolled, clonal, cellular proliferation, occurring as a result of numerous genetic, and epigenetic aberrations. Signalling pathways known to be disrupted in UM include: (1) the retinoblastoma pathway, probably as a result of cyclin D1 overexpression; p53 signalling, possibly as a consequence of MDM2 overexpression; and the P13K/AKT and mitogen-activated protein kinase/extracellular signal-related kinase pathway pathways that are disturbed as a result of PTEN and GNAQ/11 mutations, respectively. Characteristic chromosomal abnormalities are common and include 6p gain, associated with a good prognosis, as well as 1p loss, 3 loss, and 8q gain, which correlate with high mortality. These are identified by techniques such as fluorescence in situ hybridisation, comparative genomic hybridisation, microsatellite analysis, multiplex ligation-dependent probe amplification, and single-nucleotide polymorphisms. UM can also be categorised by their gene expression profiles as class 1 or class 2, the latter correlating with poor survival, as do BRCA1-associated protein-1 (BAP1) inactivating mutations. Genetic testing of UM has enhanced prognostication, especially when results are integrated with histological and clinical data. The identification of abnormal signalling pathways, genes and proteins in UM opens the way for target-based therapies, improving prospects for conserving vision and prolonging life.

Conjunctival melanoma and melanocytic intra-epithelial neoplasia.

The rarity of conjunctival melanoma has impeded progress in the management of patients with this cancer; however, much progress has occurred in recent years. Primary acquired melanosis is now differentiated histologically into hypermelanosis and conjunctival melanocytic intra-epithelial neoplasia, for which an objective reproducible scoring system has been developed. Mapping and clinical staging of conjunctival disease has improved. Adjunctive radiotherapy and topical chemotherapy have made tumour control more successful, with reduced morbidity. Genetic analyses have identified BRAF and other mutations, which may predict responsiveness to new chemotherapeutic agents, for example Vemurafenib, should metastatic disease develop. Multicentre studies are under way to enhance survival prediction by integrating clinical stage of disease with histological grade of malignancy and genetic abnormalities. Such improved prognostication would not only be more relevant to individual patients, but would also provide greater opportunities for basic science research.

Differences in uveal melanomas between men and women from the British Isles.

PURPOSE: The purpose of this study is to compare uveal melanomas (UMs) in men and women. METHODS: The Liverpool Ocular Oncology Centre (LOOC) database was reviewed. Patients treated for UM at the LOOC between 1993 and 2010 were selected. Differences between sexes were identified using the χ (2)-test for categorical variables and the Mann-Whitney test for continuous variables. RESULTS: The 3380 patients comprised 1685 women and 1695 men. The tumours were considered clinically to have arisen in choroid in 89.5%, ciliary body in 5.3%, and iris in 5.2%. Tumours in women were less likely to originate in choroid (87.2 vs 91.7%; P<0.001) and showed more circumferential spread in ciliary body (P<0.001) and iris (P=0.003). Tumours in men were more likely to extend to within 3 mm of optic disc or fovea (46.3 vs 39.0%, P<0.001), showing more extensive optic-disc involvement (P<0.001). The median largest basal tumour diameter was 12.2 mm in men and 11.9 mm in women (P=0.001). The tumour thickness had a median of 4.4 mm and 3.8 mm in men and women, respectively (P=0.015). The 180 ciliary body tumours occurred in 112 women and 68 men. In these, the prevalence of extraocular spread was higher in women (19.6 vs 8.8%; P=0.052). The 175 iris melanomas were more common in women than men (103 vs 72, respectively). CONCLUSIONS: In men, UMs tend to be larger and more posterior than in women.

A reappraisal of the significance of largest basal diameter of posterior uveal melanoma.

OBJECTIVES: To evaluate the significance of the largest tumour diameter (LTD) of posterior uveal melanomas (ie, involving choroid), correlating this feature with histological and cytogenetic predictors and mortality. METHODS: Patients with posterior uveal melanoma were included. LTD was measured by echography and correlated with histological and cytogenetic findings and metastatic death. RESULTS: The cohort comprised 1776 patients with a median age of 60 years, a median tumour diameter of 14.0 mm, and a median tumour height of 7.5 mm. The LTD was greater in older patients (t-test, P<0.001). The presence of epithelioid cells, closed loops, high mitotic rate, chromosome 3 deletion, and chromosome 8 gains all correlated significantly with LTD (t-test, P<0.001). The 1521 British patients had a median follow-up of 4.9 years, with a disease-specific mortality of 28.9%. Metastatic death correlated with LTD (Cox multivariate analysis, P<0.001). Tumours with the same LTD showed significant variation in survival, according to the presence of epithelioid cells (Log rank, P<0.001), closed loops (Log rank, P=0.002), high mitotic rate (Log rank, P=0.003), and chromosome 3 loss (Log rank, P=0.008). CONCLUSIONS: The value of LTD as a predictor of survival after treatment of posterior uveal melanoma is enhanced by taking histological and cytogenetic factors into account.