Therapeutic implications of the emerging molecular biology of uveal melanoma

The combination of PAC-1 and entrectinib for the treatment of metastatic uveal melanoma

The treatment of metastatic uveal melanoma remains a major clinical challenge. Procaspase-3, a proapoptotic protein and precursor to the key apoptotic executioner caspase-3, is overexpressed in a wide range of malignancies, and the drug PAC-1 leverages this overexpression to selectively kill cancer cells. Herein, we investigate the efficacy of PAC-1 against uveal melanoma cell lines and report the synergistic combination of PAC-1 and entrectinib. This preclinical activity, tolerability data in mice, and the known clinical effectiveness of these drugs in human cancer patients led to a small Phase 1b study in patients with metastatic uveal melanoma. The combination of PAC-1 and entrectinib was tolerated with no treatment-related grade ≥3 toxicities in these patients. The pharmacokinetics of entrectinib were not affected by PAC-1 treatment. In this small and heavily pretreated initial cohort, stable disease was observed in four out of six patients, with a median progression-free survival of 3.38 months (95% CI 1.6-6.5 months). This study is an initial demonstration that the combination of PAC-1 and entrectinib may warrant further clinical investigation. Clinical trial registration: Clinical Trials.gov: NCT04589832.

FGF-trapping hampers cancer stem-like cells in uveal melanoma

BACKGROUND

Cancer stem-like cells (CSCs) are a subpopulation of tumor cells responsible for tumor initiation, metastasis, chemoresistance, and relapse. Recently, CSCs have been identified in Uveal Melanoma (UM), which represents the most common primary tumor of the eye. UM is highly resistant to systemic chemotherapy and effective therapies aimed at improving overall survival of patients are eagerly required.

METHODS

Herein, taking advantage from a pan Fibroblast Growth Factor (FGF)-trap molecule, we singled out and analyzed a UM-CSC subset with marked stem-like properties. A hierarchical clustering of gene expression data publicly available on The Cancer Genome Atlas (TCGA) was performed to identify patients' clusters.

RESULTS

By disrupting the FGF/FGF receptor (FGFR)-mediated signaling, we unmasked an FGF-sensitive UM population characterized by increased expression of numerous stemness-related transcription factors, enhanced aldehyde dehydrogenase (ALDH) activity, and tumor-sphere formation capacity. Moreover, FGF inhibition deeply affected UM-CSC survival in vivo in a chorioallantoic membrane (CAM) tumor graft assay, resulting in the reduction of tumor growth. At clinical level, hierarchical clustering of TCGA gene expression data revealed a strong correlation between FGFs/FGFRs and stemness-related genes, allowing the identification of three distinct clusters characterized by different clinical outcomes.

CONCLUSIONS

Our findings support the evidence that the FGF/FGFR axis represents a master regulator of cancer stemness in primary UM tumors and point to anti-FGF treatments as a novel therapeutic strategy to hit the CSC component in UM.

Recurrent Alterations in the MAPK pathway in Sporadic Pyogenic Granuloma of Childhood

Pyogenic granuloma is one of the most common vascular tumours. The cause of pyogenic granuloma was previously thought to be an inflammatory reaction with consecutive stimulation of endothelial cell proliferation. However, recent studies suggest that pyogenic granuloma may be driven by constitutive activation of the mitogen-activated protein kinase pathway. The aim of this study was to investigate the molecular profile of sporadic pyogenic granuloma of childhood, using a systematic approach scrutinizing potential aberrations within different oncogenic pathways. Within a retrospective setting pyogenic granuloma of 15 patients was analysed by targeted next generation sequencing using the Oncomine Focus Assay, which includes genes of key tumorigenic signalling pathways. Activating mutations were found in 4 out of 15 cases (27%). Two HRAS hotspot mutations (p.Gly13Arg, p.Ala59Thr), 1 BRAF (p.Val600Glu) mutation and a novel, previously not reported, MAP2K1 hotspot mutation (p.Glu203Lys) were identified. It is notable that all of these genes are involved in constitutive mitogen- activated protein kinase signalling. This study increases the range of underlying genetic alterations in pyogenic granuloma by identifying novel oncogenic mutations in crucial mitogen-activated protein kinase pathway genes. The results provide supporting evidence that activated mitogen-activated protein kinase signalling is a key driver in the pathogenesis of pyogenic granuloma, which might be exploited by targeted treatment approaches for selected cases.

Specific human endogenous retroviruses predict metastatic potential in uveal melanoma

Uveal melanoma (UM) is a unique disease in that patients with primary UM are well stratified based on their risk of developing metastasis, yet there are limited effective treatments once metastases occur. There is an urgent need to better understand the distinct molecular pathogenesis of UM and the characteristics of patients at high risk for metastasis to identify neoantigenic targets that can be used in immunotherapy and to develop novel therapeutic strategies that may effectively target this lethal transition. An important and overlooked area of molecular pathogenesis and neoantigenic targets in UM comes from human endogenous retroviruses (HERVs). We investigated the HERV expression landscape in primary UM and found that tumors were stratified into 4 HERV-based subsets that provide clear delineation of risk outcome and support subtypes identified by other molecular indicators. Specific HERV loci are associated with the risk of uveal melanoma metastasis and may offer mechanistic insights into this process, including dysregulation of HERVs on chromosomes 3 and 8. A HERV signature composed of 17 loci was sufficient to classify tumors according to subtype with greater than 95% accuracy, including at least 1 intergenic HERV with coding potential (HERVE_Xp11.23) that could represent a potential HERV E target for immunotherapy.

Exploring the FGF/FGFR System in Ocular Tumors: New Insights and Perspectives

Ocular tumors are a family of rare neoplasms that develop in the eye. Depending on the type of cancer, they mainly originate from cells localized within the retina, the uvea, or the vitreous. Even though current treatments (e.g., radiotherapy, transpupillary thermotherapy, cryotherapy, chemotherapy, local resection, or enucleation) achieve the control of the local tumor in the majority of treated cases, a significant percentage of patients develop metastatic disease. In recent years, new targeting therapies and immuno-therapeutic approaches have been evaluated. Nevertheless, the search for novel targets and players is eagerly required to prevent and control tumor growth and metastasis dissemination. The fibroblast growth factor (FGF)/FGF receptor (FGFR) system consists of a family of proteins involved in a variety of physiological and pathological processes, including cancer. Indeed, tumor and stroma activation of the FGF/FGFR system plays a relevant role in tumor growth, invasion, and resistance, as well as in angiogenesis and dissemination. To date, scattered pieces of literature report that FGFs and FGFRs are expressed by a significant subset of primary eye cancers, where they play relevant and pleiotropic roles. In this review, we provide an up-to-date description of the relevant roles played by the FGF/FGFR system in ocular tumors and speculate on its possible prognostic and therapeutic exploitation.

Dual Targeting of CDK4/6 and cMET in Metastatic Uveal Melanoma

Simple Summary

Up to 50% of uveal melanoma patients subsequently develop metastases, for which no effective treatment has been identified. In this study, 87.5% of uveal melanoma patients’ samples were positive for phosphorylated retinoblastoma (RB), and ex vivo incubation of patients’ biopsy specimens with CDK4/6 inhibitor decreased the phosphorylation of RB. Hepatocyte growth factor (HGF), which is rich in the liver microenvironment, diminished the efficacy of CDK4/6 inhibitor. In human HGF knock-in NOD.Cg-Prkdc scid Il2rg tm1Wjl/SzJ mice, combination of CDK4/6 inhibitor and cMET inhibitor showed significant growth suppression in implanted metastatic uveal melanoma cells, compared to CDK4/6 inhibitor alone. Taken together, our preclinical study indicated that combining CDK4/6 inhibitor and cMET inhibitor would provide significant clinical benefit to patients with metastatic uveal melanoma.

Abstract

Uveal melanoma (UM) is the most common cancer of the eye in adults. Up to 50% of UM patients subsequently develop metastases, especially in the liver. It has been reported that the retinoblastoma (RB) pathway is deregulated in more than 90% of UM despite the rarity of mutations in the RB1 gene itself. CDK4/6 inhibition (CDK4/6i) is a rational strategy for treatment of UM. In this report, we investigated the antiproliferative activity of a selective CDK4/6 inhibitor on metastatic UM. A CDK4/6 inhibitor suppressed UM cell lines growth in in vitro and in vivo experiments. Hepatocyte growth factor (HGF) decreased the effect of CDK4/6 inhibitor on metastatic UM cell lines. When CDK4/6i was combined with cMET inhibitor, enhanced growth suppression was observed in metastatic UM tumors grown in human-HGF knock-in xenograft mouse models. HGF is enriched in the liver and the majority of liver metastases from UM express activated forms of cMET; therefore, signaling through cMET could contribute to the resistance mechanisms against CDK4/6i, especially in UM patients with hepatic metastasis. Together, these results provide a rationale for the use of cMET inhibitor in combination with a CDK4/6 inhibitor for the treatment of metastatic UM.

Emerging roles of microRNAs and their implications in uveal melanoma

Uveal melanoma (UM) is the most common intraocular malignant tumor in adults with an extremely high mortality rate. Genetic and epigenetic dysregulation contribute to the development of UM. Recent discoveries have revealed dysregulation of the expression levels of microRNAs (miRNAs) as one of the epigenetic mechanisms underlying UM tumorigenesis. Based on their roles, miRNAs are characterized as either oncogenic or tumor suppressive. This review focuses on the roles of miRNAs in UM tumorigenesis, diagnosis, and prognosis, as well as their therapeutic potentials. Particularly, the actions of collective miRNAs are summarized with respect to their involvement in major, aberrant signaling pathways that are implicated in the development and progression of UM. Elucidation of the underlying functional mechanisms and biological aspects of miRNA dysregulation in UM is invaluable in the development of miRNA-based therapeutics, which may be used in combination with conventional treatments to improve therapeutic outcomes. In addition, the expression levels of some miRNAs are correlated with UM initiation and progression and, therefore, may be used as biomarkers for diagnosis and prognosis.

Artificial intelligence for modeling uveal melanoma

Understanding of the cellular signaling pathways involved in cancer disease is of great importance. These complex biological mechanisms can be thoroughly revealed by their structure, dynamics, and control methods. Artificial intelligence offers rule-based models that favor the research of human signaling processes. In this paper, we give an overview of the advantages of the formalism of symbolic models in medical biology and cell biology of the uveal melanoma. A language is described that allows us: (1) To define the system states and elements with their alterations; (2) To model the dynamics of the cellular system; and (3) To perform inference-based analysis with the logical tools of the language.

Uveal melanoma: progress in molecular biology and therapeutics

Uveal melanoma (UM) is the most common intraocular malignancy in adults. So far, no systemic therapy or standard treatment exists to reduce the risk of metastasis and improve overall survival of patients. With the increased knowledge regarding the molecular pathways that underlie the oncogenesis of UM, it is expected that novel therapeutic approaches will be available to conquer this disease. This review provides a summary of the current knowledge of, and progress made in understanding, the pathogenesis, genetic mutations, epigenetics, and immunology of UM. With the advent of the omics era, multi-dimensional big data are publicly available, providing an innovation platform to develop effective targeted and personalized therapeutics for UM patients. Indeed, recently, a great number of therapies have been reported specifically for UM caused by oncogenic mutations, as well as other etiologies. In this review, special attention is directed to advancements in targeted therapies. In particular, we discuss the possibilities of targeting: GNAQ/GNA11, PLCβ, and CYSLTR2 mutants; regulators of G-protein signaling; the secondary messenger adenosine diphosphate (ADP)-ribosylation factor 6 (ARF6); downstream pathways, such as those involving mitogen-activated protein kinase/MEK/extracellular signal-related kinase, protein kinase C (PKC), phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR), Trio/Rho/Rac/Yes-associated protein, and inactivated BAP1; and immune-checkpoint proteins cytotoxic T-lymphocyte antigen 4 and programmed cell-death protein 1/programmed cell-death ligand 1. Furthermore, we conducted a survey of completed and ongoing clinical trials applying targeted and immune therapies for UM. Although drug combination therapy based on the signaling pathways involved in UM has made great progress, targeted therapy is still an unmet medical need.

Research in practice: Therapeutic targeting of oncogenic GNAQ mutations in uveal melanoma

Uveal melanoma is the most common form of eye cancer and has a poor prognosis. Although the primary tumor in most cases is treated effectively by local surgery or radiotherapy, over 50 % of patients develop systemic metastasis, especially in the liver. In contrast to cutaneous melanoma, there is no standard-of-care treatment for metastasized uveal melanoma. Recently, oncogenic driver mutations in GNAQ or GNA11 were identified in about 85 % of uveal melanomas, which lead to constitutively active signaling in the Gα_q/11 pathway and its downstream effectors. Direct targeting of deregulated Gα_q/11 signaling might therefore be a therapeutic option for patients with uveal melanoma. In our study we identified the cyclic depsipeptide FR-900359, which is isolated from the evergreen plant Ardisia crenata as an effective inhibitor of constitutively active Gα_q/11 proteins and their downstream targets. Although our data are preliminary, they might contribute to a future treatment option for patients with metastasized uveal melanoma.

MicroRNAs and Uveal Melanoma: Understanding the Diverse Role of These Small Molecular Regulators

Uveal melanoma (UM) is a rare tumour of the eye, characterised by a high propensity to metastasise in half of all patients, most frequently to the liver. Although there are effective treatment options for the primary tumour, once metastasis has occurred prognosis is poor, with overall survival limited to months. Currently, there are no effective treatments for metastatic UM, despite the tumour having a well-defined signalling pathway to which many therapies have been directed. In an effort to develop novel treatment approaches, understanding the role of other signalling molecules, such as microRNAs, is fundamental. MicroRNAs (miRNAs) are small non-coding RNA molecules involved in posttranscriptional gene regulation, resulting in reduced target gene expression and subsequent protein translation. In UM, several dysregulated miRNAs have been proposed to play a functional role in disease progression, whereas others have been put forward as clinical biomarkers of high-risk disease following isolation from blood, plasma and exosomes. Most recently, analyses of large datasets have identified promising prognostic miRNA signatures and panels. This review navigates the plethora of aberrant miRNAs disclosed so far in UM, and maps these to signalling pathways, which could be targeted in future therapies for the disseminated disease.

Uveal melanoma pathobiology: Metastasis to the liver

Uveal melanoma (UM) is a type of intraocular tumor with a propensity to disseminate to the liver. Despite the identification of the early driver mutations during the development of the pathology, the process of UM metastasis is still not fully comprehended. A better understanding of the genetic, molecular, and environmental factors participating to its spread and metastatic outgrowth could provide additional approaches for UM treatment. In this review, we will discuss the advances made towards the understanding of the pathogenesis of metastatic UM, summarize the current and prospective treatments, and introduce some of the ongoing research in this field.

Pristimerin-induced uveal melanoma cell death via inhibiting PI3K/Akt/FoxO3a signalling pathway

Uveal melanoma (UM) is a highly invasive intraocular malignancy with high mortality. Presently, there is no FDA‐approved standard for the treatment of metastatic UM. Pristimerin is a natural quinine methide triterpenoid compound with anti‐angiogenic, anti‐cancer and anti‐inflammatory activities. However, Pristimerin potential cytotoxic effect on UM was poorly investigated. In the present study, we found the migration and invasion of UM‐1 cells were inhibited by Pristimerin which also caused a rapid increase of ROS, decreased mitochondrial membrane potential, induced the accumulation of cells in G0/G1 phase, ending with apoptotic cell death. Pristimerin inhibited Akt and FoxO3a phosphorylation and induced nuclear accumulation of FoxO3a in UM‐1 cells, increased the expression of pro‐apoptotic proteins Bim、p27^Kip1, cleaved caspase‐3, PARP and Bax, and decreased the expression of Cyclin D1 and Bcl‐2. LY294002 or Akt‐siRNA inhibited the PI3K/Akt/FoxO3a pathway and promoted the Pristimerin‐induced apoptosis, while Pristimerin effects were partially abolished in FoxO3a knockdown UM‐1 cell cultures. Taken together, present results showed that Pristimerin induced apoptotic cell death through inhibition of PI3K/Akt/FoxO3a pathway in UM‐1 cells. These findings indicate that Pristimerin may be considered as a potential chemotherapeutic agent for patients with UM.

GNAQ and GNA11 mutant nonuveal melanoma: a subtype distinct from both cutaneous and uveal melanoma

BACKGROUND

GNAQ and GNA11 mutant nonuveal melanoma represent a poorly characterized rare subgroup of melanoma with a gene mutation profile similar to uveal melanoma.

OBJECTIVES

To characterize these tumours in terms of clinical behaviour and genetic characteristics.

METHODS

Patients with nonuveal GNAQ/11 mutated melanoma were identified from the prospective multicentre tumour tissue registry ADOREG, Tissue Registry in Melanoma (TRIM) and additional cooperating skin cancer centres. Extensive data on patient, tumour and treatment characteristics were collected retrospectively. Targeted sequencing was used to determine tumour mutational burden. Immunohistochemistry staining was performed for programmed death-ligand 1 and BRCA1-associated protein (BAP)1. Existing whole-exome cutaneous and uveal melanoma data were analysed for mutation type and burden.

RESULTS

We identified 18 patients with metastatic GNAQ/11 mutant nonuveal melanoma. Tumours had a lower tumour mutational burden and fewer ultraviolet signature mutations than cutaneous melanomas. In addition to GNAQ and GNA11 mutations (nine each), six splicing factor 3b subunit 1 (SF3B1), three eukaryotic translation initiation factor 1A X-linked (EIF1AX) and four BAP1 mutations were detected. In contrast to uveal melanoma, GNAQ/11 mutant nonuveal melanomas frequently metastasized lymphatically and concurrent EIF1AX, SF3B1 and BAP1 mutations showed no apparent association with patient prognosis. Objective response to immunotherapy was poor with only one partial response observed in 10 treated patients (10%).

CONCLUSIONS

Our findings suggest that GNAQ/11 mutant nonuveal melanomas are a subtype of melanoma that is both clinically and genetically distinct from cutaneous and uveal melanoma. As they respond poorly to available treatment regimens, novel effective therapeutic approaches for affected patients are urgently needed. What is already known about this topic? The rare occurrence of GNAQ/11 mutations in nonuveal melanoma has been documented. GNAQ/11 mutant nonuveal melanomas also harbour genetic alterations in EIF1AX, SF3B1 and BAP1 that are of prognostic relevance in uveal melanoma. What does this study add? GNAQ/11 mutant nonuveal melanomas show metastatic spread reminiscent of cutaneous melanoma, but not uveal melanoma. GNAQ/11 mutant nonuveal melanomas have a low tumour mutational burden that is higher than uveal melanoma, but lower than cutaneous melanoma. What is the translational message? Primary GNAQ/11 mutant nonuveal melanomas are a subtype of melanoma that is clinically and genetically distinct from both cutaneous and uveal melanoma. As metastatic GNAQ/11 mutant nonuveal melanomas respond poorly to available systemic therapies, including immune checkpoint inhibition, novel therapeutic approaches for these tumours are urgently needed. Linked Comment: Rafei-Shamsabadi. Br J Dermatol 2020; 183:806-807.

The Role of MET in Melanoma and Melanocytic Lesions

Melanoma is the leading cause of death due to cutaneous malignancy and its incidence is on the rise. Several signaling pathways, including receptor tyrosine kinases, have been recognized to have an etiopathogenetic role in the development and progression of precursor melanocytic lesions and malignant melanoma. Among those, the hepatocyte growth factor/MET (HGF/MET) axis is emerging as a critical player not only in the tumor itself but also in the immune microenvironment in which the tumor grows and advances in its development. Moreover, the activation of this pathway has emerged as a paradigm of tumor resistance to modern targeted therapies, and the assessment of its expression in patients' samples may be a valuable biomarker of tumor progression and response to targeted therapy. Here we summarize our current understanding of this important receptor tyrosine kinase in normal melanocyte proliferation/motility, in tumor progression and metastasis, its genetic alterations in certain subtype of melanocytic lesions, and how its pathway has been explored for the development of selective inhibitors.

Atypical presentations of congenital hemangiomas: Extending the clinical phenotype

BACKGROUND/OBJECTIVES

Congenital hemangiomas (CH) are a group of benign vascular tumors that are present at birth and exhibit variable involution during infancy. Congenital hemangiomas that do not involute are typically solitary patch or plaque-type tumors that grow proportionally with somatic growth. We report a case series of 9 patients with persistent CH, which exhibited uncommon features including segmental involvement, recurrent or severe pain, or growth via volumetric increase in size or apparent increased extent of anatomic involvement over time.

METHODS

Via retrospective chart review, we included patients with persistent CH and atypical presentations. Available data regarding clinical characteristics, natural history, histopathology, imaging, and genetic tests were collected.

RESULTS

Data on 9 patients were collected, including 7 noninvoluting CH and 2 partially involuting CH. Three of the 9 cases had segmental distribution, 6 had apparent growth or clinical evolution, and 4 were symptomatic with pain. One also had marked localized intravascular coagulopathy.

CONCLUSIONS

Ongoing or recurrent pain and large extent of anatomic involvement can be features of CH, albeit uncommon ones, and can pose both diagnostic and management challenges. Tissue genomic studies can offer a novel tool for CH diagnosis.

Emerging Therapeutic Opportunities Based on Current Knowledge of Uveal Melanoma Biology

Uveal Melanoma (UM) is a rare and malignant intraocular tumor with dismal prognosis. Despite the efficient control of the primary tumor by radiation or surgery, up to 50% of patients subsequently develop metastasis, mainly in the liver. Once the tumor has spread from the eye, the treatment is challenging and the median survival is only nine months. UM represents an intriguing model of oncogenesis that is characterized by a relatively homogeneous histopathological architecture and a low burden of genetic alterations, in contrast to other melanomas. UM is driven by recurrent activating mutations in Gαq pathway, which are associated with a second mutation in BRCA1 associated protein 1 (BAP1), splicing factor 3b subunit 1 (SF3B1), or eukaryotic translation initiation factor 1A X-linked (EIF1AX), occurring in an almost mutually exclusive manner. The monosomy of chromosome 3 is also a recurrent feature that is associated with high metastatic risk. These events driving UM oncogenesis have been thoroughly investigated over the last decade. However, no efficient related therapeutic strategies are yet available and the metastatic disease remains mostly incurable. Here, we review current knowledge regarding the molecular biology and the genetics of uveal melanoma and highlight the related therapeutic applications and perspectives.

CHOROIDAL MELANOMA, SECTOR MELANOCYTOSIS, AND RETINAL PIGMENT EPITHELIAL MICRODETACHMENTS IN BIRT-HOGG-DUBÉ SYNDROME

PURPOSE

Birt-Hogg-Dubé Syndrome (BHDS) is a rare autosomal dominant condition that can predispose patients to numerous cutaneous fibrofolliculomas and other cutaneous lesions, pulmonary cysts with spontaneous pneumothorax, and multifocal renal tumors and cancer. The genetic mutations responsible for BHDS are related to tumor suppression and the mammalian target of rapamycin (mTOR) pathway. Previous reports of the ocular findings in BHDS include eyelid fibrofolliculomas, "flecked chorioretinopathy," and one report of choroidal melanoma. We report a patient with BHDS who presented with choroidal melanoma, sector melanocytosis, and retinal pigment epithelial microdetachments.

METHODS

Observational case report.

RESULTS

A 38-year-old man with BHDS manifesting with facial fibrofolliculomas/tricodiscomas and pulmonary cysts with previous pneumothorax of both lungs was noted to have a large choroidal nevus, managed with observation elsewhere. On referral 1 year later, photopsia and visual field defect were noted, and the patient was discovered to have subtle patchy sector ocular melanocytosis of the iris and choroid with choroidal melanoma and dependent subretinal fluid. The melanoma measured 14 mm in basal dimension and 6.8 mm in thickness. In addition, pinpoint retinal pigment epithelial microdetachments were observed in both eyes at the equator and confirmed on optical coherence tomography. Custom-fit plaque radiotherapy was provided for tumor control.

CONCLUSION

The BHDS can be associated with tumors of the skin and kidney. In this case, we noted ocular melanocytosis, malignant choroidal melanoma, and bilateral pinpoint retinal pigment epithelial detachments.

Uveal Melanoma: A European Network to Face the Many Challenges of a Rare Cancer

Uveal melanoma (UM) is the most frequent primary ocular cancer in adults, accounting for 5% of all melanomas. Despite effective treatments for the primary tumour, up to 50% of UM patients will develop metastasis, leading to a very poor prognosis and a median overall survival of 6 to 12 months, with no major improvements in the last 30 years. There is no standard oncological treatment available for metastatic UM patients, and BRAF/MEK and immune checkpoint inhibitors show disappointing results when compared to cutaneous melanoma (CM). Recent advances in biology, however, identified specific gene and chromosome alterations, potentially permitting an actively tailored surveillance strategy, and dedicated clinical studies. Being a rare cancer, UM patients have to overcome issues such as identifying referral centres, having access to information, and partnering with oncologists for specific management strategies and research priorities. Here, we describe how the European Rare Adult solid Cancer Network (EURACAN) will help in addressing these challenges and accelerating international collaborations to enhance the development of innovative treatments in UM.

Ethanolic Extract of Senna velutina Roots: Chemical Composition, In Vitro and In Vivo Antitumor Effects, and B16F10-Nex2 Melanoma Cell Death Mechanisms

Cutaneous melanoma is among the most aggressive types of cancer, and its rate of occurrence increases every year. Current pharmacological treatments for melanoma are not completely effective, requiring the identification of new drugs. As an alternative, plant-derived natural compounds are described as promising sources of new anticancer drugs. In this context, the objectives of this study were to identify the chemical composition of the ethanolic extract of Senna velutina roots (ESVR), to assess its in vitro and in vivo antitumor effects on melanoma cells, and to characterize its mechanisms of action. For these purposes, the chemical constituents were identified by liquid chromatography coupled to high-resolution mass spectrometry. The in vitro activity of the extract was assessed in the B16F10-Nex2 melanoma cell line using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and based on the apoptotic cell count; DNA fragmentation; necrostatin-1 inhibition; intracellular calcium, pan-caspase, and caspase-3 activation; reactive oxygen species (ROS) levels; and cell cycle arrest. The in vivo activity of the extract was assessed in models of tumor volume progression and pulmonary nodule formation in C57Bl/6 mice. The chemical composition results showed that ESVR contains flavonoid derivatives of the catechin, anthraquinone, and piceatannol groups. The extract reduced B16F10-Nex2 cell viability and promoted apoptotic cell death as well as caspase-3 activation, with increased intracellular calcium and ROS levels as well as cell cycle arrest at the sub-G0/G1 phase. In vivo, the tumor volume progression and pulmonary metastasis of ESVR-treated mice decreased over 50%. Combined, these results show that ESVR had in vitro and in vivo antitumor effects, predominantly by apoptosis, thus demonstrating its potential as a therapeutic agent in the treatment of melanoma and other types of cancer.

Defining the Molecular Genetics of Dermoscopic Naevus Patterns

Melanocytic naevi are common melanocytic proliferations that may simulate the appearance of cutaneous melanoma. Naevi commonly harbour somatic mutations implicated in melanomagenesis but in most cases lack the necessary genomic alterations required for melanoma development. While the mitogen-activated protein kinase pathway and ultraviolet radiation strongly contribute to naevogenesis, the somatic mutational landscape of dermoscopic naevus subsets distinguishes some of the molecular hallmarks of naevi in relation to melanoma. We herein discuss the classification of naevi and theories of naevogenesis and review the current literature on the somatic alterations in naevi and melanoma. This review focusses on the clinical-dermoscopic-pathological and genomic correlation of naevi that shapes the current understanding of naevi.

Genetic prognostication in uveal melanoma

Uveal melanoma (UM) is a rare tumour with a high propensity to metastasize. Although no effective treatment for metastases yet exists, prognostication in UM is relevant for patient counselling, planning of follow-up and stratification in clinical trials. Besides conventional clinicopathologic characteristics, genetic tumour features with prognostic significance have been identified. Non-random chromosome aberrations such as monosomy 3 and gain of chromosome 8q are strongly correlated with metastatic risk, while gain of chromosome 6p indicates a low risk. Recently, mutations in genes such as BAP1, SF3B1 and EIF1AX have been shown to be related to patient outcome. Genetics of UM is a rapidly advancing field, which not only contributes to the understanding of the pathogenesis of this cancer, but also results in further refinement of prognostication. Concomitantly, advances have been made in the use of genetic tests. New methods for genetic typing of UM have been developed. Despite the considerable progress made recently, many questions remain, such as those relating to the reliability of prognostic genetic tests, and the use of biopsied or previously irradiated tumour tissue for prognostication by genetic testing. In this article, we review genetic prognostic indicators in UM, also comparing available genetic tests, addressing the clinical application of genetic prognostication and discussing future perspectives for improving genetic prognostication in UM.

Conjunctival Melanoma - Epidemiological Trends and Features

Conjunctival melanoma is a rare but sight and life threatening malignancy. It accounts for 2%-5% of all ocular tumours and 5%-7% of all ocular melanomas with an incidence of 0.2-0.8 per million in the Caucasian population with rare cases reported in the non-Caucasians. In recent decades the incidence of uveal melanoma has been relatively stable whilst conjunctival and cutaneous melanoma have shown increasing incidence which may be connected to the result of environmental exposure to ultraviolet light. The dissimilarity in incidence between light and dark pigmented individuals observed in conjunctival melanomas compared to uveal and cutaneous melanomas may be related to differences in their histological structures and genetic profile. Recent molecular biological studies support the fact that each type of melanoma undergoes its own molecular changes and has characteristic biological behaviour. Further studies are required for each type of melanoma in order to ascertain their individual etiology and pathogenesis and based on this knowledge develop relevant preventative and treatment procedures.

Gamma irradiation of ocular melanoma and lymphoma cells in the presence of gold nanoparticles: in vitro study

The aim of this work was to determine whether conjugation of cultivated choroidal melanoma and Burkitt's lymphoma cells with gold nanoparticles (GNPs) is beneficial for these series of ocular cancer patients. GNPs are radiosensitizers and can sensitize tumors to radiotherapy.This application has been examined in several tumor types, but not in choroidal melanoma. This study shows the results of in vitro study on the choroidal melanoma and also Burkitt's lymphoma cells in the presence of GNPs during continuous gamma irradiation. Cytotoxicity of GNPs were assessed for five different concentrations then cultured melanoma and Burkitt's lymphoma cells were irradiated with a Gamma source in the presence and absence of NPs. Incubation of melanoma cells with GNP concentrations below 100 μg/ml, accompanied by gamma irradiation, increased cell death (P value = 0.016) . In the absence of irradiation, GNPs at these concentrations did not affect cultured melanoma cell metabolism. Reduced cell viability resulted from a significant increase in absorbed energy by the tumor. Moreover, GNP concentrations higher than 200 μg/ml induced cytotoxicity in melanoma cells. Cytotoxicity assay in GNPs-loaded Burkitt's lymphoma cells showed a slight decrease in cell viability at 50 μg/ml and clear cytotoxicity at concentrations higher than 100 μg/ml (P value = 0.035). Concentration and proper injection doses of GNPs in sensitive tissues such as the human eye are important variables yet to be determined.This is the first report of choroidal melanoma dosimetry performed in the presence of GNPs and provides valuable insights into future therapeutic approaches. Further in vitro study with more different sizes and concentrations is needed to determine the optimum size and concentration before any clinical research in this regard.

The mTOR inhibitor Everolimus synergizes with the PI3K inhibitor GDC0941 to enhance anti-tumor efficacy in uveal melanoma

Uveal melanoma (UM) is the most frequent malignant ocular tumor in adults. While the primary tumor is efficiently treated by surgery and/or radiotherapy, about one third of UM patients develop metastases, for which no effective treatment is currently available. The PKC, MAPK and PI3K/AKT/mTOR signaling cascades have been shown to be associated with tumor growth. However, none of the compounds against those pathways results in tumor regression when used as single agents. To identify more effective therapeutic strategies for UM patients, we performed a combination screen using seven targeted agents inhibiting PKC, MEK, AKT, PI3K and mTOR in a panel of ten UM cell lines, representative of the UM disease. We identified a strong synergy between the mTOR inhibitor Everolimus and the PI3K inhibitor GDC0941. This combination resulted in an increase in apoptosis in several UM cell lines compared to monotherapies and enhanced the anti-tumor effect of each single agent in two patient-derived xenografts. Furthermore, we showed that the synergism between the two drugs was associated with the relief by GDC0491 of a reactivation of AKT induced by Everolimus. Altogether, our results highlight a novel and effective combination strategy, which could be beneficial for UM patients.

Dual inhibition of protein kinase C and p53-MDM2 or PKC and mTORC1 are novel efficient therapeutic approaches for uveal melanoma

Uveal melanoma (UM) is the most common cancer of the eye in adults. Many UM patients develop metastases for which no curative treatment has been identified. Novel therapeutic approaches are therefore urgently needed. UM is characterized by mutations in the genes GNAQ and GNA11 which activate the PKC pathway, leading to the use of PKC inhibitors as a rational strategy to treat UM tumors. Encouraging clinical activity has been noted in UM patients treated with PKC inhibitors. However, it is likely that curative treatment regimens will require a combination of targeted therapeutic agents. Employing a large panel of UM patient-derived xenograft models (PDXs), several PKC inhibitor-based combinations were tested in vivo using the PKC inhibitor AEB071. The most promising approaches were further investigated in vitro using our unique panel of UM cell lines. When combined with AEB071, the two agents CGM097 (p53-MDM2 inhibitor) and RAD001 (mTORC1 inhibitor) demonstrated greater activity than single agents, with tumor regression observed in several UM PDXs. Follow-up studies in UM cell lines on these two drug associations confirmed their combination activity and ability to induce cell death. While no effective treatment currently exists for metastatic uveal melanoma, we have discovered using our unique panel of preclinical models that combinations between PKC/mTOR inhibitors and PKC/p53-MDM2 inhibitors are two novel and very effective therapeutic approaches for this disease. Together, our study reveals that combining PKC and p53-MDM2 or mTORC1 inhibitors may provide significant clinical benefit for UM patients.

DNA Methylomes Reveal Biological Networks Involved in Human Eye Development, Functions and Associated Disorders

This work provides a comprehensive CpG methylation landscape of the different layers of the human eye that unveils the gene networks associated with their biological functions and how these are disrupted in common visual disorders. Herein, we firstly determined the role of CpG methylation in the regulation of ocular tissue-specification and described hypermethylation of retinal transcription factors (i.e., PAX6, RAX, SIX6) in a tissue-dependent manner. Second, we have characterized the DNA methylome of visual disorders linked to internal and external environmental factors. Main conclusions allow certifying that crucial pathways related to Wnt-MAPK signaling pathways or neuroinflammation are epigenetically controlled in the fibrotic disorders involved in retinal detachment, but results also reinforced the contribution of neurovascularization (ETS1, HES5, PRDM16) in diabetic retinopathy. Finally, we had studied the methylome in the most frequent intraocular tumors in adults and children (uveal melanoma and retinoblastoma, respectively). We observed that hypermethylation of tumor suppressor genes is a frequent event in ocular tumors, but also unmethylation is associated with tumorogenesis. Interestingly, unmethylation of the proto-oncogen RAB31 was a predictor of metastasis risk in uveal melanoma. Loss of methylation of the oncogenic mir-17-92 cluster was detected in primary tissues but also in blood from patients.

Recent advances in uveal melanoma treatment

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Recent advances in the understanding of molecular characteristics helped to determine which tumors are most likely to progress. About 50% of patients carrying genetic alterations such as chromosomal aberrations and mutations are at significant risk for metastatic disease of which the majority will succumb to UM within few months. Currently, there is no effective treatment for metastatic uveal melanoma, and we hope this review will encourage researchers and clinicians to work to find a better standard of care. In this article we provide a comprehensive overview of the molecular framework of UM, highlighting the most common mutations involved in this kind of cancer. It also covers the most recent treatments from basic research to clinical trials, including small molecules, nucleic acids or immunotherapy, among others. It is intended to serve as a key reference for clinicians and researchers working in this field.

Sporadic melanotic schwannoma with overlapping features of melanocytoma bearing a GNA11 mutation in an adolescent girl

Melanotic schwannoma (MS) is a soft tissue neoplasm that shares histologic features with melanocytic tumors and schwannomas. A type of MS, called psammomatous MS (PMS), is associated with Carney complex (CNC), which is caused by PRKAR1A mutations. Other pigmented neoplasms, such as uveal melanomas and melanocytomas (MCs), are associated with genetic defects in other genes including GNA11. We report an adolescent female with a large sporadic mesenteric MS with complex histologic findings reminiscent of both PMS and MC. The lesion carried a mutation of the GNA11 gene. We conclude that sporadic MSs may occur rarely in adolescents without CNC; MSs may also be associated with somatic GNA11 mutations.

Co-targeting HGF/cMET Signaling with MEK Inhibitors in Metastatic Uveal Melanoma

Patients with metastatic uveal melanoma usually die within 1 year of diagnosis, emphasizing an urgent need to develop new treatment strategies. The liver is the most common site of metastasis. Mitogen-activated protein kinase kinase (MEK) inhibitors improve survival in V600 BRAF-mutated cutaneous melanoma patients but have limited efficacy in patients with uveal melanoma. Our previous work showed that hepatocyte growth factor (HGF) signaling elicits resistance to MEK inhibitors in metastatic uveal melanoma. In this study, we demonstrate that expression of two BH3-only family proteins, Bim-EL and Bmf, contributes to HGF-mediated resistance to MEK inhibitors. Targeting HGF/cMET signaling with LY2875358, a neutralizing and internalizing anti-cMET bivalent antibody, and LY2801653, a dual cMET/RON inhibitor, overcomes resistance to trametinib provided by exogenous HGF and by conditioned medium from primary hepatic stellate cells. We further determined that activation of PI3Kα/γ/δ isoforms mediates the resistance to MEK inhibitors by HGF. Combination of LY2801653 with trametinib decreases AKT phosphorylation and promotes proapoptotic PARP cleavage in metastatic uveal melanoma explants. Together, our data support the notion that selectively blocking cMET signaling or PI3K isoforms in metastatic uveal melanoma may break the intrinsic resistance to MEK inhibitors provided by factors from stromal cells in the liver. Mol Cancer Ther; 16(3); 516-28. ©2017 AACR.

Dysregulated GPCR Signaling and Therapeutic Options in Uveal Melanoma

Uveal melanoma is the most common primary intraocular malignant tumor in adults and arises from the transformation of melanocytes in the uveal tract. Even after treatment of the primary tumor, up to 50% of patients succumb to metastatic disease. The liver is the predominant organ of metastasis. There is an important need to provide effective treatment options for advanced stage uveal melanoma. To provide the preclinical basis for new treatments, it is important to understand the molecular underpinnings of the disease. Recent genomic studies have shown that mutations within components of G protein-coupled receptor (GPCR) signaling are early events associated with approximately 98% of uveal melanomas.Implications: This review discusses the alterations in GPCR signaling components (GNAQ and GNA11), dysregulated GPCR signaling cascades, and viable targeted therapies with the intent to provide insight into new therapeutic strategies in uveal melanoma. Mol Cancer Res; 15(5); 501-6. ©2017 AACR.

Phase II randomised discontinuation trial of the MET/VEGF receptor inhibitor cabozantinib in metastatic melanoma

BACKGROUND

A phase II randomised discontinuation trial assessed cabozantinib (XL184), an orally bioavailable inhibitor of tyrosine kinases including VEGF receptors, MET, and AXL, in a cohort of patients with metastatic melanoma.

METHODS

Patients received cabozantinib 100 mg daily during a 12-week lead-in. Patients with stable disease (SD) per Response Evaluation Criteria in Solid Tumours (RECIST) at week 12 were randomised to cabozantinib or placebo. Primary endpoints were objective response rate (ORR) at week 12 and postrandomisation progression-free survival (PFS).

RESULTS

Seventy-seven patients were enroled (62% cutaneous, 30% uveal, and 8% mucosal). At week 12, the ORR was 5%; 39% of patients had SD. During the lead-in phase, reduction in target lesions from baseline was seen in 55% of evaluable patients overall and in 59% of evaluable patients with uveal melanoma. Median PFS after randomisation was 4.1 months with cabozantinib and 2.8 months with placebo (hazard ratio of 0.59; P=0.284). Median PFS from study day 1 was 3.8 months, 6-month PFS was 33%, and median overall survival was 9.4 months. The most common grade 3/4 adverse events were fatigue (14%), hypertension (10%), and abdominal pain (8%). One treatment-related death was reported from peritonitis due to diverticular perforation.

CONCLUSIONS

Cabozantinib has clinical activity in patients with metastatic melanoma, including uveal melanoma. Further clinical investigation is warranted.

Serum adiponectin, insulin resistance, and uveal melanoma: clinicopathological correlations

To investigate the status of insulin resistance, metabolic syndrome, dyslipidemia, and serum adiponectin levels in patients with uveal melanoma and choroidal nevus were investigated. Our study included 86 patients with uveal melanoma, 38 patients with choroidal nevus, and 86 controls. Uveal melanomas were classified as small, medium, and large on the basis of Collaborative Ocular Melanoma Study (COMS) criteria. Patients with uveal melanoma had significantly higher homeostatic model assessment scores compared with patients with choroidal nevus (P<0.001). Patients with uveal melanoma and choroidal nevus had significantly lower levels of serum adiponectin compared with controls (P<0.001). Patients with uveal melanoma who developed systemic metastases had significantly lower levels of serum adiponectin levels compared with patients with nonmetastases during follow-up (P=0.018). When the largest tumors (COMS III) were compared, ciliary body melanomas were associated with significantly lower levels of serum adiponectin than choroidal melanomas. In patients who were treated with enucleation, epitheloid predominant and mixed cell-type tumors were associated with lower levels of serum adiponectin compared with tumors with spindle cell type, but this did not reach statistical significance. By providing an antiapoptotic and proangiogenic environment, low serum adiponectin levels and insulin resistance may play a role in promoting the growth of uveal melanocytic tumors and may contribute toward a more aggressive clinical course, adversely affecting the prognosis.

Ocular oncology: advances in retinoblastoma, uveal melanoma and conjunctival melanoma

BACKGROUND

Retinoblastoma, uveal and conjunctival melanomas are important malignancies within the remit of ocular oncology. Outlined are the diagnostic features and management principles, as well as advancements in the field and current challenges.

SOURCES OF DATA

Original papers, reviews and guidelines.

AREAS OF AGREEMENT

Most eyes with retinoblastoma (International Intraocular Retinoblastoma Classification (IIRC) Group A-D) are salvaged, whereas advanced cases (Group E) remain a challenge. Despite a high rate of local tumour control in uveal melanoma, metastatic spread commonly occurs. Conjunctival melanoma is treated by complete resection, but high rates of local recurrence occur, with the possibility of systemic relapse and death.

AREAS OF CONTROVERSY

Use of the IIRC in retinoblastoma, and systemic screening in melanomas.

GROWING POINTS

Utilization of novel treatment modalities in retinoblastoma and an increasing understanding of the genetic basis of melanomas.

AREAS TIMELY FOR DEVELOPING RESEARCH

Improvements in chemotherapy delivery in retinoblastoma and prognostic tests in melanomas.

The genetics of uveal melanoma: current insights

Uveal melanoma (UM) is the most common malignant eye tumor in adults affecting ~7,000 individuals per year worldwide. UM is a rare subtype of melanoma with distinct clinical and molecular features as compared to other melanoma subtypes. UMs lack the most typical cutaneous melanoma-associated mutations (BRAF, NRAS, and NF1) and are instead characterized by a different set of genes with oncogenic or loss-of-function mutations. By next-generation sequencing efforts on UM tumors, several driver genes have been detected. The most frequent ones are BAP1, EIF1AX, GNA11, GNAQ, and SF3B1. In many cases, mutations in these genes appear in a mutually exclusive manner, have different risk of metastasis, and are consequently of prognostic importance. The majority of UM cases are sporadic but a few percentage of the cases occurs in families with an inherited predisposition for this malignancy. In recent years, germline mutations in the BAP1 gene have been found to segregate in an autosomal dominant pattern with numerous different cancer types including UM in cancer-prone families. This cancer syndrome has been denoted as the tumor predisposition syndrome.

BRD4-targeted therapy induces Myc-independent cytotoxicity in Gnaq/11-mutatant uveal melanoma cells

Uveal melanoma (UM) is an aggressive intraocular malignancy with limited therapeutic options. Both primary and metastatic UM are characterized by oncogenic mutations in the G-protein alpha subunit q and 11. Furthermore, nearly 40% of UM has amplification of the chromosomal arm 8q and monosomy of chromosome 3, with consequent anomalies of MYC copy number. Chromatin regulators have become attractive targets for cancer therapy. In particular, the bromodomain and extra-terminal (BET) inhibitor JQ1 has shown selective inhibition of c-Myc expression with antiproliferative activity in hematopoietic and solid tumors. Here we provide evidence that JQ1 had cytotoxic activity in UM cell lines carrying Gnaq/11 mutations, while in cells without the mutations had little effects. Using microarray analysis, we identified a large subset of genes modulated by JQ1 involved in the regulation of cell cycle, apoptosis and DNA repair. Further analysis of selected genes determined that the concomitant silencing of Bcl-xL and Rad51 represented the minimal requirement to mimic the apoptotic effects of JQ1 in the mutant cells, independently of c-Myc. In addition, administration of JQ1 to mouse xenograft models of Gnaq-mutant UM resulted in significant inhibition of tumor growth.

Collectively, our results define BRD4 targeting as a novel therapeutic intervention against UM with Gnaq/Gna11 mutations.

P2RX7-V3 is a novel oncogene that promotes tumorigenesis in uveal melanoma

Uveal melanoma (UM) has a high mortality rate for primary intraocular tumors. Approximately half of UM patients present with untreatable and fatal metastases. Long non-coding RNAs (lncRNAs) have emerged as potent regulatory RNAs that play key roles in various cellular processes and tumorigenesis. However, to date, their roles in UM are not well-known. Here, we identified a transcriptional variant transcribed from the P2RX7 gene locus, named P2RX7-V3 (P2RX7 variant 3), which was expressed at a high level in UM cells. P2RX7-V3 silencing revealed that this variant acts as a necessary UM oncoRNA. Knockdown of P2RX7-V3 expression significantly suppressed tumor growth in vitro and in vivo. A genome-wide cDNA array revealed that a variety of genes were dysregulated following P2RX7-V3 silencing. These observations identified P2RX7-V3 that plays a crucial role in UM tumorigenesis and may serve as a useful biomarker in the diagnosis and prognosis treatment of UM in the future.

Ocular brachytherapy dosimetry for 103Pd and 125I in the presence of gold nanoparticles: a Monte Carlo study

The aim of the present Monte Carlo study is to evaluate the variation of energy deposition in healthy tissues in the human eye which is irradiated by brachytherapy sources in comparison with the resultant dose increase in the gold nanoparticle (GNP)-loaded choroidal melanoma. The effects of these nanoparticles on normal tissues are compared between 103Pd and 125I as two ophthalmic brachytherapy sources. Dose distribution in the tumor and healthy tissues has been taken into account for both brachytherapy sources. Also, in certain points of the eye, the ratio of the absorbed dose by the normal tissue in the presence of GNPs to the absorbed dose by the same point in the absence of GNPs has been calculated. In addition, differences of the absorbed dose in the tumor observed in the comparison of simple water phantom and actual simulated human eye in presence of GNPs are also a matter of interest that have been considered in the present work. The difference between the eye globe and the water phantom is more obvious for 125I than that of the 103Pd when the ophthalmic dosimetry is done in the presence of GNPs. Whenever these nanoparticles are utilized in enhancing the absorbed dose by the tumor, the use of 125I brachytherapy source will greatly amplify the amount of dose enhancement factor (DEF) in the tumor site without inflicting much dam-age to healthy organs, when compared to the 103Pd source. For instance, in the concentration of 30 mg GNPs, the difference amongst the calculated DEF for 125I between these phantoms is 5.3%, while it is 2.45% for 103Pd. Furthermore, in Monte Carlo studies of eye brachytherapy, more precise definition of the eye phantom instead of a water phantom will become increasingly important when we use 125I as opposed to 103Pd.

Selumetinib for the treatment of metastatic uveal melanoma: past and future perspectives

Uveal melanoma is a rare but aggressive subtype of melanoma. Nearly 50% of patients will develop metastatic disease despite primary enucleation or radiation therapy. There is currently no standard of care therapy for metastatic uveal melanoma, and no therapy that has been shown to prolong overall survival. Uveal melanoma is characterized by activation of signaling pathways including the MAPK pathway and the PI3K/AKT pathway, among others, via mutations in the G-α-proteins GNAQ and GNA11. MEK inhibition with selumetinib has been evaluated as a therapeutic strategy in metastatic uveal melanoma. This review will discuss preclinical and clinical studies evaluating selumetinib in metastatic uveal melanoma, as well as potential future perspectives on MEK inhibition in the management of metastatic uveal melanoma.

Whole-genome copy-number analysis identifies new leads for chromosomal aberrations involved in the oncogenesis and metastastic behavior of uveal melanomas

To further elucidate the genetic underpinnings of uveal melanoma (UM) and identify new markers that correlate with disease outcome, archival formalin-fixed, paraffin-embedded enucleation specimens from 25 patients with UM and a mean follow-up of 14 years were analyzed for whole-genome copy-number alterations using OncoScan analysis. Copy-number alterations of chromosomes 1, 3, 6, and 8 were also analyzed in these tumors using multiplex ligation-dependent probe-amplification, and mutations in GNAQ, GNA11, and BAP1 were searched for by Sanger sequencing. Our study confirms the previously reported GNAQ and GNA11 mutation frequencies in UMs as well as the presence of monosomy 3 as a factor strongly indicating poor prognosis. Two cases with metastatic disease, but without monosomy of chromosome 3, showed loss of a small region in the distal part of chromosome 2p. Also, UMs leading to metastatic disease had more chromosomal aberrations than those without metastases. Three UMs lacking a GNAQ or a GNA11 mutation showed a gain of chromosome 8q; one of these cases showed extensive chromothripsis. Another case (with suspect lung metastasis) showed focal chromothripsis. Our whole-genome copy-number analysis shows that focal loss of chromosome 2p may be involved in the metastatic spread of UMs without monosomy 3; metastatic UMs carry more chromosomal aberrations than those without metastases; and chromothripsis may play a role in the oncogenesis of UMs, but does not necessarily indicate a poor prognosis. The clinical and particularly diagnostic utility of these findings needs to be corroborated in a larger set of patients with UM.

Treatment of Uveal Melanoma

Uveal melanoma (UM) comprises approximately 5 % of all melanoma diagnoses in the USA each year. Approximately half of patients with UM eventually develop metastases, most commonly involving the liver. Historically, prognosis for these patients has been poor, with death occurring 6-12 months from the time of metastases. Multiple trials of cytotoxic treatments largely extrapolated from cutaneous melanoma have been ineffective in metastatic UM. Trials of regional hepatic-directed therapy have led to high response rates, but these have yet to be translated into a survival benefit. Recently, it was discovered that the majority of UMs harbor activating mutations in genes encoding one of two G-alpha protein subunits, GNAQ and GNA11. This knowledge has led to the rational development of clinical trials specifically for UM utilizing targeted inhibitors of the activated signaling pathways such as mitogen-activated protein kinase, Akt, and protein kinase C. A recent trial of the oral MEK inhibitor selumetinib was the first to show clinical benefit for any systemic therapy in a randomized fashion. This increasing understanding of the biology of UM offers hope that novel treatments will continue to benefit patients with metastatic disease.

The biology and clinical development of MEK inhibitors for cancer

The mitogen-activated protein kinase kinases (MAPKK) MEK1 and MEK2 are integral members of the MAPK/ERK signaling pathway and are of interest in the development of anti-cancer therapeutics. The MAPK/ERK pathway is dysregulated in more than 30 % of cancers, predominately by mutations in RAS and BRAF proteins, and MEK serves as a potential downstream target for both of these. The biology of MEK inhibition is complex, as the molecule is differentially regulated by upstream RAS or RAF. This has impacted on the past development of MEK inhibitors as treatments for cancer and may be exploited in more rational, molecularly selected drug development plans in the future. The role of MEK in cancer and the mechanism of action of MEK inhibitors is reviewed. Furthermore, MEK inhibitors that are available in standard practice, as well as those most advanced in clinical development, are discussed. Finally, next steps in the development of MEK inhibitors are considered.

Uveal Melanoma Patient-Derived Xenografts

The prognosis of uveal melanoma (UM) remains poor due to a high risk of metastatic disease. No effective therapies have been described for metastatic UM, and new therapies are needed to improve the outcome for these patients. To achieve this goal, new preclinical animal models are needed. Existing animal models, including genetically engineered mice and orthotopic xenograft models in immunodeficient animals, are inadequate for modelling human disease. In this review, we present the development and characterization of a large panel of UM patient-derived xenografts (PDXs). Based on molecular features as identified in patient tumors, i.e. histopathological classification, specific gene mutations, as well as genomic and gene expression profiles, we show that PDXs closely resemble many important genetic and histological aspects of human UM with a remarkable stability over the course of their in vivo maintenance. Our techniques for establishing and maintaining primary UMs as xenograft tumors in immunodeficient mice provide a high degree of genetic conservation between the primary tumor and its xenograft over multiple in vivo passages. These models therefore represent a significant advance in the resources available for drug screening and studies of the pathogenesis of UM.