Progression of ocular melanoma metastasis to the liver: the 2012 Zimmerman lecture

Lineage commitment pathways epigenetically oppose oncogenic Gαq/11-YAP signaling in dormant disseminated uveal melanoma

The mechanisms driving late relapse in uveal melanoma (UM) patients remains a medical mystery and major challenge. Clinically it is inferred that UM disseminated cancer cells (DCCs) persist asymptomatic for years-to-decades mainly in the liver before they manifest as symptomatic metastasis. Here we reveal using Gαq/11 mut /BAP wt human uveal melanoma models and human UM metastatic samples, that the neural crest lineage commitment nuclear receptor NR2F1 is a key regulator of spontaneous UM DCC dormancy in the liver. Using a quiescence reporter, RNA-seq and multiplex imaging we revealed that rare dormant UM DCCs upregulate NR2F1 expression and genes related to neural crest programs while repressing gene related to cell cycle progression. Gain and loss of function assays showed that NR2F1 silences YAP1/TEAD1 transcription downstream of Gαq/11 signaling and that NR2F1 expression can also be repressed by YAP1. YAP1 expression is repressed by NR2F1 binding to its promoter and changing the histone H3 tail activation marks to repress YAP1 transcription. In vivo CRISPR KO of NR2F1 led dormant UM DCCs to awaken and initiate relentless liver metastatic growth. Cut&Run and bulk RNA sequencing further confirmed that NR2F1 epigenetically stimulates neuron axon guidance and neural lineage programs, and it globally represses gene expression linked to G-protein signaling to drive dormancy. Pharmacological inhibition of Gαq/11 mut signaling resulted in NR2F1 upregulation and robust UM growth arrest, which was also achieved using a novel NR2F1 agonist. Our work sheds light on the molecular underpinnings of UM dormancy revealing that transcriptional programs driven by NR2F1 epigenetically short-circuit Gαq/11 signaling to its downstream target YAP1.

Highlights

Quiescent solitary uveal melanoma (UM) DCCs in the liver up- and down-regulate neural crest and cell cycle progression programs, respectively.NR2F1 drives solitary UM DCC dormancy by antagonizing the Gαq/11-YAP1 pathway; small molecule Gαq/11 inhibition restores NR2F1 expression and quiescence. NR2F1 short-circuits oncogenic YAP1 and G-protein signaling via a chromatin remodeling program. Loss of function of NR2F1 in dormant UM DCCs leads to aggressive liver metastasis.

Graphical abstract

From Molecular Biology to Novel Immunotherapies and Nanomedicine in Uveal Melanoma

Molecular biology studies of uveal melanoma have resulted in the development of novel immunotherapy approaches including tebentafusp-a T cell-redirecting bispecific fusion protein. More biomarkers are currently being studied. As a result, combined immunotherapy is being developed as well as immunotherapy with bifunctional checkpoint inhibitory T cell engagers and natural killer cells. Current trials cover tumor-infiltrating lymphocytes (TIL), vaccination with IKKb-matured dendritic cells, or autologous dendritic cells loaded with autologous tumor RNA. Another potential approach to treat UM could be based on T cell receptor engineering rather than antibody modification. Immune-mobilizing monoclonal T cell receptors (TCR) against cancer, called ImmTAC TM molecules, represent such an approach. Moreover, nanomedicine, especially miRNA approaches, are promising for future trials. Finally, theranostic radiopharmaceuticals enabling diagnosis and therapy with the same molecule bring hope to this research.

Patient-derived zebrafish xenografts of uveal melanoma reveal ferroptosis as a drug target

Uveal melanoma (UM) has a high risk to progress to metastatic disease with a median survival of 3.9 months after metastases detection, as metastatic UM responds poorly to conventional and targeted chemotherapy and is largely refractory to immunotherapy. Here, we present a patient-derived zebrafish UM xenograft model mimicking metastatic UM. Cells isolated from Xmm66 spheroids derived from metastatic UM patient material were injected into 2 days-old zebrafish larvae resulting in micro-metastases in the liver and caudal hematopoietic tissue. Metastasis formation could be reduced by navitoclax and more efficiently by the combinations navitoclax/everolimus and flavopiridol/quisinostat. We obtained spheroid cultures from 14 metastatic and 10 primary UM tissues, which were used for xenografts with a success rate of 100%. Importantly, the ferroptosis-related genes GPX4 and SLC7A11 are negatively correlated with the survival of UM patients (TCGA: n = 80; Leiden University Medical Centre cohort: n = 64), ferroptosis susceptibility is correlated with loss of BAP1, one of the key prognosticators for metastatic UM, and ferroptosis induction greatly reduced metastasis formation in the UM xenograft model. Collectively, we have established a patient-derived animal model for metastatic UM and identified ferroptosis induction as a possible therapeutic strategy for the treatment of UM patients.

Acousto-Optics: Recent Studies and Medical Applications

Development of acousto-optic (AO) techniques has made progress in recent years across a range of medical application fields, especially in improving resolution, detection speed, and imaging depth. This paper presents a comprehensive overview of recent advancements in AO-based techniques that have been presented after the previously published review in 2017. The survey covers a description of theoretical modeling strategies and numerical simulation methods as well as recent applications in medical fields. It also provides a comparison between different techniques in terms of complexity, achieved depth in tissue, and resolution. In addition, a comparison between different numerical simulation methods will be outlined. Additionally, a number of challenges faced by AO techniques are considered, particularly in the context of realistic in vivo imaging. Finally, the paper discusses prospects of AO-based medical diagnosis methods.

Extracellular Vesicles from Ocular Melanoma Have Pro-Fibrotic and Pro-Angiogenic Properties on the Tumor Microenvironment

Uveal melanoma (UM) is the most common primary intraocular tumor and often spreads to the liver. Intercellular communication though extracellular vesicles (EVs) plays an important role in several oncogenic processes, including metastasis, therapeutic resistance, and immune escape. This study examines how EVs released by UM cells modify stellate and endothelial cells in the tumor microenvironment. The surface markers, and the concentration and size of EVs derived from UM cells or choroidal melanocytes were characterized by high-resolution flow cytometry, electron microscopy, and Western blotting. The selective biodistribution of EVs was studied in mice by fluorescence imaging. The activation/contractility of stellate cells and the tubular organization of endothelial cells after exposure to melanomic EVs were determined by traction force microscopy, collagen gel contraction, or endothelial tube formation assays. We showed that large EVs from UM cells and healthy melanocytes are heterogenous in size, as well as their expression of phosphatidylserine, tetraspanins, and Tsg101. Melanomic EVs mainly accumulated in the liver and lungs of mice. Hepatic stellate cells with internalized melanomic EVs had increased contractility, whereas EV-treated endothelial cells developed more capillary-like networks. Our study demonstrates that the transfer of EVs from UM cells leads to a pro-fibrotic and pro-angiogenic phenotype in hepatic stellate and endothelial cells.

Myeloid-derived Suppressor Cells Activate Liver Natural Killer Cells in a Murine Model in Uveal Melanoma

OBJECTIVE

Elevated myeloid-derived suppressor cells (MDSCs) in many malignancies are associated with the increased risk for metastases and poor prognosis. Therefore, a mouse model of intraocular melanoma was established to explore how MDSCs influence liver metastases.

METHODS

In this study, murine B16LS melanoma cells were transplanted into the posterior compartment (PC) of the eye of C57BL/6 mice. Leucocytes from the liver of naive mice and mice bearing melanoma liver metastasis were isolated using isotonic Percoll centrifugation, examined by flow cytometry for their expression of Gr1, CD11b, F4/80, RAE-1, and Mult-1, and further isolated for MDSCs and natural killer (NK) cells. The effects of MDSCs on NK cells were tested by coculturing and assessing the ability of NK cells to produce interferon-gamma (IFN-γ) by ELISA and NK cell cytotoxicity by ³H-thymidine incorporation assay. The impact of IFN-γ on liver metastases was examined via selectively depleting IFN-γ in vivo.

RESULTS

The results showed that mice with liver metastases had increased levels of CD11b⁺Gr1⁺F4/80⁺ as well as CD11b⁺Gr1⁺F4/80^- MDSCs. MDSCs significantly enhanced the generation of IFN-γ together with the cytotoxicity of the NK cells. Furthermore, these effects were cell-cell contact-dependent. Although IFN-γ was not of a toxic nature to the melanoma cells, it profoundly inhibited B16LS cell proliferation. Depleting IFN-γ in vivo led to increased liver metastases.

CONCLUSION

All these findings first revealed that MDSCs accumulated in liver metastasis of intraocular melanoma could activate the NK cells to produce an effective anti-tumor immune response. Thus, the MDSCs' performance in different tumor models would need more investigation to boost current immunotherapy modalities.

Histopathological growth patterns of liver metastasis: updated consensus guidelines for pattern scoring, perspectives and recent mechanistic insights

The first consensus guidelines for scoring the histopathological growth patterns (HGPs) of liver metastases were established in 2017. Since then, numerous studies have applied these guidelines, have further substantiated the potential clinical value of the HGPs in patients with liver metastases from various tumour types and are starting to shed light on the biology of the distinct HGPs. In the present guidelines, we give an overview of these studies, discuss novel strategies for predicting the HGPs of liver metastases, such as deep-learning algorithms for whole-slide histopathology images and medical imaging, and highlight liver metastasis animal models that exhibit features of the different HGPs. Based on a pooled analysis of large cohorts of patients with liver-metastatic colorectal cancer, we propose a new cut-off to categorise patients according to the HGPs. An up-to-date standard method for HGP assessment within liver metastases is also presented with the aim of incorporating HGPs into the decision-making processes surrounding the treatment of patients with liver-metastatic cancer. Finally, we propose hypotheses on the cellular and molecular mechanisms that drive the biology of the different HGPs, opening some exciting preclinical and clinical research perspectives.

Characterizing metastatic uveal melanoma patients who develop symptomatic brain metastases

Metastatic uveal melanoma (mUM) is an advanced ocular malignancy characterized by a hepatotropic pattern of spread. As the incidence of brain metastases (BM) in mUM patients has been thought to be low, routine CNS surveillance has not been recommended. Notably, no formal assessment of BM incidence in mUM has to date been published to support this clinical practice. We aimed to determine the true rate of BM in mUM and to clarify the clinical and genomic risk factors associated with BM patients through a collaborative multicenter, retrospective research effort. Data collected from 1,845 mUM patients in databases across four NCI-designated comprehensive cancer centers from 2006-2021 were retrospectively analyzed to identify patients with BM. Brain imaging in most cases were performed due to onset of neurological symptoms and not for routine surveillance. An analysis of demographics, therapies, gene expression profile, tumor next generation sequencing (NGS) data, time to metastasis (brain or other), and survival in the BM cohort was completed. 116/1,845 (6.3%) mUM patients were identified with BM. The median age at time of UM diagnosis was 54 years old (range: 18-77). The median time to any metastasis was 4.2 years (range: 0-30.8). The most common initial metastatic site was the liver (75.9%). 15/116 (12.9%) BM patients presented with BM at the time of initial metastatic diagnosis. Median survival after a diagnosis of BM was 7.6 months (range: 0.4-73.9). The median number of organs involved at time of BM diagnosis was 3 (range: 1-9). DecisionDX-UM profiling was completed on 13 patients: 10-Class 2, 2-Class 1B, and 1-Class 1A. NGS and cytogenetic data were available for 34 and 21 patients, respectively. BM was identified in 6.3% of mUM cases and was associated with high disease burden and a median survival of under 8 months once diagnosed. Since most patients in this cohort were symptomatic, the incidence of asymptomatic BM remains unknown. These data suggest the use of routine brain imaging in all mUM patients at risk for developing BM for early detection.

Evaluation of HSP-27, BAP1, BRAF V600E, CCR7, and PD-L1 expression in uveal melanoma on enucleated eyes and metastatic liver tumors

BACKGROUND

The presence of metastatic disease is one of the most important factors limiting survival in patients with uveal melanoma. Studies on proteins associated with metastatic mechanisms are sparse in the literature.

METHODS

Enucleation samples from 15 patients with metastatic uveal melanoma (Group 1), liver metastasectomy samples from 8 patients with metastatic uveal melanoma (Group 2), and enucleation samples from 20 patients with non-metastatic uveal melanoma as controls (Group 3) were included in the study. Antibodies against heat shock protein 27 (HSP-27), BRCA1-associated protein-1 (BAP1), C-C chemokine receptor 7 (CCR7), B-Raf proto-oncogene serine/threonine-protein kinase V600E (BRAF V600E), and programmed death-ligand 1 (PD-L1) were used to detect immunoreactivity in each sample by immunohistochemical methods. Correlations between these expressed proteins and selected histopathological and clinical features, and metastatic process were investigated.

RESULTS

The frequencies of HSP-27 (median score: Group 1: 8, Group 2: 12, Group 3: 4) and BRAF V600E expressions (number of samples: Group 1: 4 (26.7%), Group 2: 1 (12.5%), Group 3: 0 (0%)), and BAP1 expression loss (number of samples : Group 1: 12 (80%), Group 2: 8 (100%), Group 3: 9 (45%)) were higher in samples from patients with metastatic uveal melanoma (Group 1 + 2) than in those from patients with non-metastatic disease (Group 3) (P = 0.001, P = 0.034, and P = 0.007, respectively). CCR7 expression (median score: Group 1: 0, Group 2: 2, Group 3: 3) was similar among these three groups (P = 0.136). No samples exhibited PD-L1 expression (P = 1.000). One-unit increases in the HSP-27 expression level and BAP1 expression loss were significantly related to 1.375- and 7.855-fold increases in the risk of metastasis, respectively (P = 0.007 and P = 0.017).

CONCLUSION

HSP-27 and BAP1 are considered to be associated with metastasis, indicating these proteins as potential treatment targets in metastatic uveal melanoma.

Metastatic uveal melanoma: The final frontier

Treatment of primary intraocular uveal melanoma has developed considerably, its driver genes are largely unraveled, and the ways to assess its risk for metastases are very precise, being based on an international staging system and genetic data. Unfortunately, the risk of distant metastases, which emerge in approximately one half of all patients, is unaltered. Metastases are the leading single cause of death after uveal melanoma is diagnosed, yet no consensus exists regarding surveillance, staging, and treatment of disseminated disease, and survival has not improved until recently. The final frontier in conquering uveal melanoma lies in solving these issues to cure metastatic disease. Most studies on metastatic uveal melanoma are small, uncontrolled, retrospective, and do not report staging. Meta-analyses confirm a median overall survival of 10-13 months, and a cure rate that approaches nil, although survival exceeding 5 years is possible, estimated 2% either with first-line treatment or with best supportive care. Hepatic ultrasonography and magnetic resonance imaging as surveillance methods have a sensitivity of 95-100% and 83-100%, respectively, to detect metastases without radiation hazard according to prevailing evidence, but computed tomography is necessary for staging. No blood-based tests additional to liver function tests are generally accepted. Three validated staging systems predict, each in defined situations, overall survival after metastasis. Their essential components include measures of tumor burden, liver function, and performance status or metastasis free interval. Age and gender may additionally influence survival. Exceptional mutational events in metastases may make them susceptible to checkpoint inhibitors. In a large meta-analysis, surgical treatment was associated with 6 months longer median overall survival as compared to conventional chemotherapy and, recently, tebentafusp as first-line treatment at the first interim analysis of a randomized phase III trial likewise provided a 6 months longer median overall survival compared to investigator's choice, mostly pembrolizumab; these treatments currently apply to selected patients. Promoting dormancy of micrometastases, harmonizing surveillance protocols, promoting staging, identifying predictive factors, initiating controlled clinical trials, and standardizing reporting will be critical steppingstones in reaching the final frontier of curing metastatic uveal melanoma.

Non-invasive detection and complementary diagnosis of liver metastases via chemokine receptor 4 imaging

Noninvasive detection of early-stage liver metastases from different primary cancers is a pressing unmet medical need. The lack of both molecular biomarkers and the sensitive imaging methodology makes the detection challenging. In this study, we observed the elevated expression of chemokine receptor 4 (CXCR4) in uveal melanoma (UM) patient liver tissues, and high CXCR4 expression in liver metastases of UM murine models, regardless of the expression levels in the primary tumors. Based on these findings, we identified CXCR4 as an imaging biomarker and exploited a CXCR4-targeted MRI contrast agent ProCA32.CXCR4 for molecular MRI imaging. ProCA32.CXCR4 has strong CXCR4 binding affinity, high metal selectivity, and r1 and r2 relaxivities, which enables the sensitive detection of liver micrometastases. The MRI imaging capacity for detecting liver metastases was demonstrated in three UM models and one ovarian cancer model. The imaging results were validated by histological and immunohistochemical analysis. ProCA32.CXCR4 has strong potential clinical application for non-invasive diagnosis of liver metastases.

Radiological Patterns of Uveal Melanoma Liver Metastases in Correlation to Genetic Status

This study reports the role played by the mutation status of Uveal Melanoma (UM) in relation to hepatic metastatic patterns as seen on imaging modalities. Radiological images were obtained from 123 patients treated at the Erasmus Medical Center Rotterdam or the Rotterdam Eye Hospital. Radiological images were derived from either computed tomography or magnetic resonance imaging. Hepatic metastatic patterns were classified by counting the number of metastases found in the liver. Miliary metastatic pattern (innumerable small metastases in the entire liver) was analyzed separately. Mutation status was determined in 85 patients. Median disease-free survival (DFS) and survival with metastases differed significantly between each of the metastatic patterns (respectively, p = 0.009, p < 0.001), both in favor of patients with less hepatic metastases. The mutation status of the primary tumor was not correlated with any hepatic tumor profiles (p = 0.296). Of the patients who had a solitary metastasis (n = 18), 11 originated from a primary BAP1-mutated tumors and one from a primary SF3B1-mutated tumor. Of the patients who had a miliary metastasis pattern (n = 24), 17 had a primary BAP1-mutated tumor and two had a primary SF3B1-mutated tumor. Chromosome 8p loss was significantly more in patients with more metastases (p = 0.045). Moreover, the primary UMs of patients with miliary metastases harbored more chromosome 8p and 1p loss, compared to patients with single solitary metastasis (p = 0.035 and p = 0.026, respectively). In conclusion, our study shows that there is an inverse correlation of the number of metastasis with the DFS and metastasized survival, indicating separate growth patterns. We also revealed that the number and type of metastases is irrelevant to the prognostic mutation status of the tumor, showing that both BAP1- and SF3B1-mutated UM can result in solitary and miliary metastases, indicating that other processes lay ground to the different metastatic patterns.

CRISPR activation screen in mice identifies novel membrane proteins enhancing pulmonary metastatic colonisation

Melanoma represents ~5% of all cutaneous malignancies, yet accounts for the majority of skin cancer deaths due to its propensity to metastasise. To develop new therapies, novel target molecules must to be identified and the accessibility of cell surface proteins makes them attractive targets. Using CRISPR activation technology, we screened a library of guide RNAs targeting membrane protein-encoding genes to identify cell surface molecules whose upregulation enhances the metastatic pulmonary colonisation capabilities of tumour cells in vivo. We show that upregulated expression of the cell surface protein LRRN4CL led to increased pulmonary metastases in mice. Critically, LRRN4CL expression was elevated in melanoma patient samples, with high expression levels correlating with decreased survival. Collectively, our findings uncover an unappreciated role for LRRN4CL in the outcome of melanoma patients and identifies a potential therapeutic target and biomarker.

Breast cancer liver metastasis: current and future treatment approaches

Nearly all fatalities arising from breast tumors are attributable to distant metastases. Breast cancer liver metastasis (BCLM) is associated with poor prognoses, with the median survival time being 2 to 3 years. Tumor intrinsic subtype directs preferential metastasis to specific organs, with HER2-enriched tumors demonstrating the highest rates of metastasis to the liver, though all subtypes can grow in the liver. There is no singular established standard-of-care for BCLM; therapeutic selection is driven by histologic and molecular hallmarks of the primary tumor or biopsied metastasis samples. Given the poor prognosis of patients with hepatic spread, pre-clinical studies are necessary to identify and evaluate promising new treatment strategies. It is critical that these laboratory studies accurately recapitulate the BCLM disease process, standard progression, and histological attributes. In this review, we summarize the histologic and molecular characteristics of BCLM, evaluate the efficacy of existing surgical and medical treatment strategies, and discuss future approaches to preclinical study of BCLM.

Role of Natural Killer Cells in Uveal Melanoma

Simple Summary

Metastatic Uveal Melanoma (MUM) is a lethal malignancy with no durable treatment available to date. A vast majority of patients with MUM present with liver metastasis. The liver harbors metastatic disease with an apparent lack of a cytotoxic T cell response. It is becoming evident that MUM is not an immunologically silent malignancy and the investigation of non-T cell anti-tumor immunity is warranted. In this review, we highlight the relevance of Natural Killer (NK) cells in the biology and treatment of MUM. Potent anti-NK cell immunosuppression employed by uveal melanoma alludes to its vulnerability to NK cell cytotoxicity. On the contrary, micro-metastasis in the liver survive for several years within close vicinity of a plethora of circulating and liver-resident NK cells. This review provides unique perspectives into the potential role of NK cells in control or progression of uveal melanoma.

Abstract

Uveal melanoma has a high mortality rate following metastasis to the liver. Despite advances in systemic immune therapy, treatment of metastatic uveal melanoma (MUM) has failed to achieve long term durable responses. Barriers to success with immune therapy include the immune regulatory nature of uveal melanoma as well as the immune tolerant environment of the liver. To adequately harness the anti-tumor potential of the immune system, non-T cell-based approaches need to be explored. Natural Killer (NK) cells possess potent ability to target tumor cells via innate and adaptive responses. In this review, we discuss evidence that highlights the role of NK cell surveillance and targeting of uveal melanoma. We also discuss the repertoire of intra-hepatic NK cells. The human liver has a vast and diverse lymphoid population and NK cells comprise 50% of the hepatic lymphocytes. Hepatic NK cells share a common niche with uveal melanoma micro-metastasis within the liver sinusoids. It is, therefore, crucial to understand and investigate the role of intra-hepatic NK cells in the control or progression of MUM.

Molecular Insights and Emerging Strategies for Treatment of Metastatic Uveal Melanoma

Uveal melanoma (UM) is the most common intraocular cancer. In recent decades, major advances have been achieved in the diagnosis and prognosis of UM allowing for tailored treatments. However, nearly 50% of patients still develop metastatic disease with survival rates of less than 1 year. There is currently no standard of adjuvant and metastatic treatment in UM, and available therapies are ineffective resulting from cutaneous melanoma protocols. Advances and novel treatment options including liver-directed therapies, immunotherapy, and targeted-therapy have been investigated in UM-dedicated clinical trials on single compounds or combinational therapies, with promising results. Therapies aimed at prolonging or targeting metastatic tumor dormancy provided encouraging results in other cancers, and need to be explored in UM. In this review, the latest progress in the diagnosis, prognosis, and treatment of UM in adjuvant and metastatic settings are discussed. In addition, novel insights into tumor genetics, biology and immunology, and the mechanisms underlying metastatic dormancy are discussed. As evident from the numerous studies discussed in this review, the increasing knowledge of this disease and the promising results from testing of novel individualized therapies could offer future perspectives for translating in clinical use.

Identification of differentially expressed metastatic genes and their signatures to predict the overall survival of uveal melanoma patients by bioinformatics analysis

AIM

To identify metastatic genes and miRNAs and to investigate the metastatic mechanism of uveal melanoma (UVM).

METHODS

GSE27831, GSE39717, and GSE73652 gene expression profiles were downloaded from the Gene Expression Omnibus (GEO) database, and the limma R package was used to identify differentially expressed genes (DEGs). Gene Ontology (GO) term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed using the DAVID online tool. A comprehensive list of interacting DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database and Cytoscape software. The Cytoscape MCODE plug-in was used to identify clustered sub-networks and modules of hub genes from the protein-protein interaction network. GEPIA online software was used for survival analysis of UVM patients (n=80) from the The Cancer Genome Atlas (TCGA) cohort. OncomiR online software was used to find that the miRNAs were associated with UVM prognosis from the TCGA cohort. TargetScan Human 7.2 software was then used to identify the miRNAs targeting the genes.

RESULTS

There were 1600 up-regulated genes and 1399 down-regulated genes. The up-regulated genes were mainly involved in protein translation in the cytosol, whereas the down-regulated genes were correlated with extracellular matrix organization and cell adhesion in the extracellular space. Among the 2999 DEGs, five genes, Znf391, Mrps11, Htra3, Sulf2, and Smarcd3 were potential predictors of UVM prognosis. Otherwise, three miRNAs, hsa-miR-509-3-5p, hsa-miR-513a-5p, and hsa-miR-1269a were associated with UVM prognosis.

CONCLUSION

After analyzing the metastasis-related enriched terms and signaling pathways, the up-regulated DEGs are mainly involved in protein synthesis and cell proliferation by ribosome and mitogen-activated protein kinase (MAPK) pathways. However, the down-regulated DEGs are mainly involved in processes that reduced cell-cell adhesion and promoted cell migration in the extracellular matrix through PI3K-Akt signaling pathway, focal adhesion, and extracellular matrix-receptor interactions. Bioinformatics and interaction analysis may provide new insights on the events leading up to the development and progression of UVM.

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.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

Molecular imaging of extracellular matrix proteins with targeted probes using magnetic resonance imaging

The extracellular matrix (ECM) consists of proteins and carbohydrates that supports different biological structures and processes such as tissue development, elasticity, and preservation of organ structure. Diseases involving inflammation, fibrosis, tumor invasion, and injury are all attributed to the transition of the ECM from homeostasis to remodeling, which can significantly change the biochemical and biomechanical features of ECM components. While contrast agents have played an indispensable role in facilitating clinical diagnosis of diseases using magnetic resonance imaging (MRI), there is a strong need to develop novel biomarker-targeted imaging probes for in vivo visualization of biological processes and pathological alterations at a cellular and molecular level, for both early diagnosis and monitoring drug treatment. Herein, we will first review the pathological accumulation and characterization of ECM proteins recognized as important molecular features of diseases. Developments in MRI probes targeting ECM proteins such as collagen, fibronectin, and elastin via conjugation of existing contrast agents to targeting moieties and their applications to various diseases, are also reviewed. We have also reviewed our progress in the development of collagen-targeted protein MRI contrast agent with significant improvement in relaxivity and metal binding specificity, and their applications in early detection of fibrosis and metastatic cancer. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging Biology-Inspired Nanomaterials > Peptide-Based Structures Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

Chemokine receptor 4 targeted protein MRI contrast agent for early detection of liver metastases

Liver metastases often progress from primary cancers including uveal melanoma (UM), breast, and colon cancer. Molecular biomarker imaging is a new non-invasive approach for detecting early stage tumors. Here, we report the elevated expression of chemokine receptor 4 (CXCR4) in liver metastases in UM patients and metastatic UM mouse models, and development of a CXCR4-targeted MRI contrast agent, ProCA32.CXCR4, for sensitive MRI detection of UM liver metastases. ProCA32.CXCR4 exhibits high relaxivities (r ₁ = 30.9 mM^-1 s^-1, r ₂ = 43.2 mM^-1 s^-1, 1.5 T; r ₁ = 23.5 mM^-1 s^-1, r ₂ = 98.6 mM^-1 s^-1, 7.0 T), strong CXCR4 binding (K _d = 1.10 ± 0.18 μM), CXCR4 molecular imaging capability in metastatic and intrahepatic xenotransplantation UM mouse models. ProCA32.CXCR4 enables detecting UM liver metastases as small as 0.1 mm³. Further development of the CXCR4-targeted imaging agent should have strong translation potential for early detection, surveillance, and treatment stratification of liver metastases patients.

Association of Uveal Melanoma Metastatic Rate With Stochastic Mutation Rate and Type of Mutation

Importance

It is necessary to understand the mechanisms of metastasis of uveal melanoma to advise patients and develop treatments for this tumor.

Objective

To examine the stochastic properties of primary uveal melanoma including the mutation rate as a function of tumor size and metastatic rate relative to the type of mutation.

Design, Setting, and Participants

We computed the mutation rate in different sized uveal melanomas using previously published large data sets. Tumor volume was estimated using the spherical cap method. We also calculated the metastatic rate using an updated data set of patients with uveal melanoma with known mutations in BAP1, SF3B1, and EIF1AX provided by the Rotterdam Ocular Melanoma Study Group. Data were analyzed from 2 studies, one taking place from August 25, 1970, to August 27, 2008, and the other taking place between 1993 and 2013. Data were analyzed between 2016 and 2017.

Main Outcomes and Measures

Mutation rates and metastic rates.

Results

Based on the 5-year metastatic rates, mutation rates ranged from 1.09 × 10-8 to 7.86 × 10-7 per cell division, using our calculation algorithm. A higher mutation rate was found for tumors with smaller thicknesses. EIF1AX mutations were not exclusive of other mutations because 2 cases with EIF1AX mutations and metastasis also had BAP1 mutations. None of the tumors with only an EIF1AX mutation metastasized. After plotting the yearly metastatic rate vs time after treatment, we observed a small peak at 1 year and a large peak at 3.5 years after treatment for BAP1 mutations, with peaks between 2 and 3 years and at 7 years for SF3B1 mutations.

Conclusions and Relevance

We observed a higher mutation rate for smaller tumors, which may be explained by a greater number of cell divisions occurring during the expansion phase of smaller uveal melanomas. Regarding time to clinically detected metastases, the first 2 peaks appear to be associated with BAP1-mutated tumors and the late peak to SF3B1-mutated tumors.

A prospective trial of adjuvant therapy for high-risk uveal melanoma: assessing 5-year survival outcomes

Background/aims

Survival after diagnosis of metastasis from uveal melanoma is poor. Identifying individuals at high risk for metastasis and developing adjuvant therapy to prevent clinically apparent metastasis could improve survival. We conducted an adjuvant trial of sequential, low-dose dacarbazine (DTIC) and interferon-alpha-2b (IFN-α−2b) in patients with cytogenetic high-risk uveal melanoma.

Methods

Patients diagnosed with iris, ciliary body or choroidal melanoma with high-risk tumour cytogenetics (monosomy 3) were offered adjuvant treatment with low-dose DTIC and IFN-α−2b following primary therapy. Eligible but not enrolled patients were observed for comparison. DTIC was administered at 850 mg/m2 intravenously on days 1 and 28. IFN-α−2b was administered at 3 million units three times a week subcutaneously for 24 weeks beginning at week 9. Hepatic imaging was performed prior to adjuvant therapy and then at least every 6 months. Survival data were collected for 5 years after enrolment.

Results

33 patients (22%) were enrolled (treatment group), 29 (19%) were eligible but did not enrol (observation group) and 88 (59%) were not eligible. The 5-year metastasis-free survival (MFS) was 64%±9% for treated and 33%±10% for observed patients (p=0.05). The 5-year overall survival (OS) rate was 66%±9% for treated and 37%±10% for observed patients (p=0.02).

Conclusions

When adjusted for differences in age, tumour size and initial treatment, survival between treated and observed patients was no longer significant (p=0.56 MFS and p=0.92 OS). Differences in baseline tumour characteristics between treated and observed patients can influence interpretation of results.

Trial registration number

NCT01100528.

Synergic Interactions Between Hepatic Stellate Cells and Uveal Melanoma in Metastatic Growth

Uveal melanoma (UM) is a malignant intraocular tumor that spreads to the liver in half of the cases. Since hepatic cells could play a role in the therapeutic resistance of metastatic UM, the purpose of our study was to investigate the pro-invasive role of hepatic stellate cells (HSteCs) in metastatic UM at the micro- and macro-metastatic stages. We first performed an immunostaining with the alpha-smooth muscle actin (αSMA) to localize activated HSteCs in UM liver macro-metastases from four patients. Their accumulation of collagen was assessed with Masson’s Trichrome stain. Next, we inoculated metastatic UM cells alone or with human HSteCs in triple-immunodeficient mice, in order to determine if HSteCs are recruited as early as the micro-metastatic stage. The growth of metastatic foci was imaged in the liver by ex vivo fluorescence imaging. Histological analyses were performed with Masson’s Trichrome and Picrosirius Red stains, and antibodies against Melan-A and αSMA. The collagen content was measured in xenografts by quantitative polarization microscopy. In patient hepatectomy samples, activated HSteCs and their pathological matrix were localized surrounding the malignant lesions. In the mouse xenograft model, the number of hepatic metastases was increased when human HSteCs were co-inoculated. Histological analyses revealed a significant recruitment of HSteCs near the micro/macrolesions, and an increase in fibrillar collagen production. Our results show that HSteCs can provide a permissive microenvironment and might increase the therapeutic resistance of metastatic UM.

Tris DBA palladium is an orally available inhibitor of GNAQ mutant uveal melanoma in vivo

Uveal melanoma is a rare but often lethal malignancy and is the leading cause of death due to an ophthalmic condition. Uveal melanoma is often diagnosed at a late stage and has a strong propensity to hepatic metastasis. Recently, the most common driver mutations in uveal melanoma have been identified, predominantly in the G-proteins GNAQ. This pattern differs from that of cutaneous melanoma in which Braf and Nras predominate. There are no current clinically used agents that target GNAQ mutations, unlike the use of Braf inhibitors in cutaneous melanoma. We tested the novel agent Tris DBA palladium and found that it was markedly more effective against GNAQ mutant melanomas than wild type uveal melanomas. Given that ARF6 has recently been discovered as a node in GNAQ mutations, we evaluated the efficacy of Tris DBA palladium on ARF6 signaling and found that it was effective in inhibiting ARF6 activation. Finally, Tris DBA palladium was orally effective against GNAQ mutant melanoma in vivo. Tris DBA Palladium deserves further evaluation as a systemic agent for uveal melanoma.

The bidirectional crosstalk between metastatic uveal melanoma cells and hepatic stellate cells engenders an inflammatory microenvironment

Uveal melanoma is the most common primary ocular neoplasm in adults. It is peculiar for its hematogenous dissemination and its high propensity to spread to the liver. Current treatments rarely prolong patient survival. We hypothesized that metastatic uveal melanoma cells modulate the function of surrounding hepatic stellate cells to facilitate their own growth and survival. This study was conducted to investigate the role of the hepatic microenvironment on uveal melanoma aggressiveness. We demonstrated that the paracrine signaling of surrounding hepatic stellate cells have more transcriptional impact on metastatic uveal melanoma cells. Upregulated transcripts were linked to inflammation and included several interleukins. The uveal melanoma-stellate cell crosstalk induced as well the expression of transmembrane integrins. In addition, the interleukin-6 receptor inhibitor Tocilizumab did not reduce the growth of uveal melanoma cells. Our results provide evidence that inflammatory mediators are key players in the homing of uveal melanoma cells to the liver. The bidirectional crosstalk between uveal melanoma cells and hepatic stellate cells involved pro-fibrogenic interleukins. The inflammatory characteristics of the metastatic microenvironment might offer relevant therapeutic opportunities in uveal melanoma.

Replacement and desmoplastic histopathological growth patterns: A pilot study of prediction of outcome in patients with uveal melanoma liver metastases

Up to 50% of uveal melanomas (UM) metastasise to the liver within 10 years of diagnosis, and these almost always prove rapidly fatal. As histopathological growth patterns (HGPs) of liver metastases of the replacement and desmoplastic type, particularly from colon and breast carcinoma, may import valuable biological and prognostic information, we have studied HGP in a series of 41 UM liver metastases originating from 41 patients from the period 2006–2017. Twenty patients underwent enucleation while 21 had radiation therapy. Analysis of UM by array comparative genomic hybridisation revealed: 25 (64%) patients with high risk (monosomy3/8q gain); 13 (33%) intermediate risk (M3/8normal or disomy3/8q gain); and 1 low risk (disomy3/8normal). The principal HGP was replacement in 30 (73%) cases and desmoplastic in 11 (27%) cases. Cases with replacement demonstrated striking vascular co‐option/angiotropism. With the development of liver metastasis, only the replacement pattern, largest primary tumour diameter, and R2 (incomplete resection) status predicted diminished overall survival (OS; p < 0.041, p < 0.017, p < 0.047, respectively). On multivariate analysis, only HGP (hazard ratio; HR = 6.51, p = 0.008) and resection status remained significant. The genomic high‐risk variable had no prognostic value at this stage of liver metastasis. Chi‐square test showed no association of HGP with monosomy 3 or 8q gain. Eighteen of 41 (44%) patients are alive with disease and 23 (56%) patients died with follow‐up ranging from 12 to 318 months (mean: 70 months, median: 47 months). In conclusion, we report for the first time the frequency of the replacement and desmoplastic HGPs in liver UM metastases resected from living patients, and their potential important prognostic value for UM patients, as in other solid cancers. These results may potentially be utilised to develop radiological correlates and therapeutic targets for following and treating patients with UM metastases.

Privileged portal metastasis of hepatocellular carcinoma in light of the coevolution of a visceral portal system and liver in the chordate lineage: a search for therapeutic targets

Hepatocellular carcinoma (HCC) disseminates systemically, but metastases occur in distant organs only in minority of patients, whereas HCC routinely metastasizes to liver and its vessels. HCC cells disseminate via hepatic veins, but portal veins are affected by metastasis more frequently than are hepatic veins, and correlates with poor prognosis. In this review, I suggest that privileged HCC portal metastasis occurs because of high levels of pancreatic family hormones and growth factors (PHGFs) in the portal blood. The analysis suggests that the appearance of the portal system carrying PHGFs in the evolution of invertebrate chordate (Amphioxus) led to the evolution of the liver in vertebrate; given that the portal pattern of HCC metastasis and selection of more-aggressive clones are PHGF dependent, PHGFs and their ligands constitute therapeutic targets.

Radiologic and Histopathologic Correlation of Different Growth Patterns of Metastatic Uveal Melanoma to the Liver

PURPOSE

The purpose of this study was to correlate magnetic resonance imaging (MRI) radiographic results with histopathologic growth patterns of metastatic uveal melanoma (UM) to the liver.

DESIGN

Clinicopathologic correlation.

PARTICIPANTS

Patients with metastatic UM to the liver.

METHODS

A retrospective review of MRI images of patients with metastatic UM to the liver at a single institution between 2004 and 2016 was performed. The MRI growth patterns were classified as nodular or diffuse. The histopathologic findings of core liver biopsies of liver metastases identified by needle localization in a subset of these patients were reviewed. The core samples were evaluated by routine light microscopy, including immunohistochemical/immunofluorescent staining for CD31, CD105, and HMB45, and classified as exhibiting an infiltrative or nodular growth pattern.

MAIN OUTCOME MEASURES

Magnetic resonance images and core biopsy findings.

RESULTS

A total of 32 patients were identified with metastatic UM to the liver that was imaged by MRI, and 127 lesions were identified. A total of 46 lesions were classified by MRI as infiltrative and 81 as nodular. There were 9 needle-localized core biopsies that corresponded to MRI of metastatic lesions. Of these 9 lesions, 3 that were classified as infiltrative on MRI exhibited stage I infiltrative histologic growth patterns; of the remaining 6 that were classified as nodular by MRI, 5 histologically demonstrated stage II or stage III infiltrative growth patterns and 1 histologically demonstrated a nodular growth pattern.

CONCLUSIONS

Magnetic resonance imaging of hepatic infiltrative growth patterns of metastatic UM corresponded to stage I histologic infiltrative growth in the sinusoidal spaces, whereas MRI nodular growth patterns corresponded to stage II/III histologic infiltrative growth that replaced the hepatic lobule or histologic nodular growth in the portal triad that effaced adjacent hepatic parenchyma.

Inflammatory cell infiltrates in advanced metastatic uveal melanoma

Current treatments for metastatic uveal melanoma (mUM) are limited and rarely prolong patient survival. Immunotherapy trials for mUM are few and to date have demonstrated only marginal success. High densities of tumor-associated macrophages (TAMs) and infiltrating T lymphocytes (TILs) in primary UM are associated with poor prognosis. Little is known about the immune microenvironment of mUM. Our aim was to examine the presence and distribution of TAMs and TILs in mUM within the liver. Whole-tissue sections of liver mUM (n=35) were examined by immunohistochemistry. For TAMs, monoclonal antibodies against CD68 and CD163 were used. Macrophage density and morphology were scored using previous established systems. Density and spatial distribution of TILs were highlighted using antibodies against CD3 (pan-lymphocyte marker), CD4 (T-helper cells), and CD8 (T-cytotoxic cells). CD68+ and CD163+ TAMs were seen within the tumor in all 35 specimens; their density was "moderate" in 50% of cases and "few" in 43%, and the majority showed an "indeterminate" phenotype. CD3+ TILs were noted both within mUMs and surrounding the tumor. Of these, CD8+ TILs were "few" in number within mUM but were predominantly seen peritumorally at the tumor/normal liver interface, whereas CD4+ TILs showed a high perivascular density within mUM. CD68+ and CD163+ TAMs of "indeterminate" morphology were observed in mUM, suggesting a tendency toward the protumorigenic M2 phenotype. CD4+ TILs were seen within the mUM, whereas CD8+ TILs tended to be peritumoral. The biological and functional roles of inflammatory cells in mUM require further investigation to determine if they represent potential targets for future therapies in mUM.

Giant Orbital Melanoma in a Heroin Abuser

Purpose

The aim of this report was to report a heroin abuser with nondiagnosed giant uveal melanoma infiltrating the orbit and prolapsing through the face.

Methods

We conducted a case report of the patient with giant melanoma.

Results

In March 2013, a 39-year-old male with bleeding from the right side of his face was taken to the Emergency Center of the University Hospital Bratislava by ambulance. The heroin abusing, homeless male who had never been treated before reported a 2-year history of a prolapsed, dark colored mass from his eye. Acute computed tomography confirmed a solid mass 20 × 20 cm prolapsing from the orbit. The patient rejected primary care, accepted only 1 transfusion and left the hospital. Two months later, he was admitted to the hospital due to anemia after many collapses. Liver metastasis was present. Surgical palliative therapy was not possible due to his general status. The patient started fractionated external radiotherapy with 8.0 Gy Co⁶⁰. Histopathological examination of the biopsy specimen showed malignant melanoma of the epitheloid type G2–3. The patient died in December 2013.

Conclusion

Extraorbital formation of a melanoma mass may progress to a giant volume, and without treatment, led to metastases in the liver and to death after 9 months in our patient with anemia.

The Toll-like receptor 5 agonist entolimod suppresses hepatic metastases in a murine model of ocular melanoma via an NK cell-dependent mechanism

Uveal melanoma (UM) is the most common primary cancer of the eye in adults and progresses to metastatic disease predominantly of the liver in ∼50% of patients. In these cases, life expectancy averages just 9 months due to the lack of effective treatment options. The Toll-like receptor 5 (TLR5) agonist entolimod (former name CBLB502) rapidly activates TLR5-NF-κB signaling in hepatocytes and suppresses growth of both TLR5-expressing and non-expressing tumors in the liver through mobilization and activation of innate and adaptive immune mechanisms. The goal of this study was to explore the potential of entolimod as an immunotherapeutic agent against hepatic metastasis of UM using the TLR5-positive B16LS9 mouse model of ocular melanoma. Mice were given seven subcutaneous injections of vehicle or entolimod given 72 h apart started one day before, on the same day or three days after intraocular injection of B16LS9 cells. All tested regimens of entolimod treatment resulted in significantly reduced B16LS9 metastasis to the liver. Entolimod induced mobilization of natural killer (NK) cells to the liver and stimulated their maturation, differentiation and activation. Antibody-mediated depletion of NK cells from mice abrogated entolimod's antimetastatic activity in the liver and eliminated the entolimod-elicited in vitro cytotoxic activity of hepatic lymphocytes against B16LS9 cells. These results provide pre-clinical evidence of entolimod's efficacy against hepatometastasis of UM and support its further development as an anticancer immunotherapeutic drug.

Metastatic ocular melanoma to the liver exhibits infiltrative and nodular growth patterns

We examined liver specimens from 15 patients with uveal melanoma (UM) who had died of their disseminated disease. We found 2 distinct growth patterns of UM metastasis: infiltrative (n = 12) and nodular (n = 3). In the infiltrative pattern, individual UM cells with a CD133+ cancer stem cell-like phenotype were present and formed aggregates of stage I <50-μm-diameter micrometastases in the sinusoidal spaces. These micrometastases appeared to expand, destroy adjacent hepatocytes, and form stage II 51- to 500-μm-diameter and then stage III >500μm-diameter metastases, which were encapsulated by collagenized fibrous septae. In the nodular growth pattern, CD133+ melanoma cells aggregated adjacent to portal venules and subsequently appeared to grow and efface the adjacent hepatocytes to form stage II 51- to 500-μm-diameter nodules that surrounded the portal venule. These avascular nodules appeared to further expand to form stage III >500-μm-diameter nodules that exhibited vascularization with minimal fibrosis. The tumor stem cell-like phenotype seen in individual UM cells was lost as the tumors progressed. There were CD56+ natural killer cells in sinusoidal spaces and CD3+ lymphocytes in periportal areas. The nodular growth pattern showed UM cells expressing MMP9 and VEGF. UM cells in both above-described growth patterns exhibited variable BAP1 expression. We propose that changes in the liver microenvironment are related to metastatic UM growth. We hypothesize that these changes include immune regulation within the sinusoidal space for the infiltrative pattern and changes in the VEGF/PEDF ratio for the nodular pattern.

Tumor Characteristics, Genetics, Management, and the Risk of Metastasis in Uveal Melanoma

Uveal melanoma is the most common intraocular malignancy in adults. Although rates of local control for uveal melanoma exceed 95% with radiotherapy or enucleation, as many as 50% of patients develop hematogenous metastases, which manifest in the decades following initial diagnosis and are uniformly and rapidly fatal. Recent compelling evidence suggests that not all uveal melanomas are themselves equivalent with respect to metastatic potential and patient survival. This review focuses on the mounting evidence of survival disparities based on intrinsic tumor clinical and histopathologic characteristics and based on tumor genetics and gene expression profiles.

Prognostic factors of choroidal melanoma in Slovenia, 1986-2008

Introduction

Choroidal melanoma is the most common primary malignancy of the eye, which frequently metastasizes. The Cancer Registry of Slovenia reported the incidence of choroid melanoma from 1983 to 2009 as stable, at 7.8 cases/million for men and 7.4/million for women. The aim of the retrospective study was to determinate the prognostic factors of survival for choroidal melanoma patients in Slovenia.

Patients and methods

From January 1986 to December 2008 we treated 288 patients with malignant choroidal melanoma; 127 patients were treated by brachytherapy with beta rays emitting ruthenium-106 applicators; 161 patients were treated by enucleation.

Results

Patients with tumours thickness < 7.2 mm and base diameter < 16 mm were treated by brachytherapy and had 5- and 10-year overall mortality 13% and 32%, respectively. In enucleated patients, 5- and 10-year mortality was higher, 46% and 69%, respectively, because their tumours were larger. Thirty patients treated by brachytherapy developed local recurrence. Twenty five of 127 patients treated by brachytherapy and 86 of 161 enucleated patients developed distant metastases. Patients of age ≥ 60 years had significantly lower survival in both treatment modalities. For patients treated by brachytherapy the diameter of the tumour base and treatment time were independent prognostic factors for overall survival, for patients treated by enucleation age and histological type of tumour were independent prognosticators. In first few years after either of treatments, the melanoma specific annual mortality rate increased, especially in older patients, and then slowly decreased.

Conclusions

It seems that particularly younger patients with early tumours can be cured, whereby preference should be given to eyesight preserving brachytherapy over enucleation.

Reduction of Nodular Growth Pattern of Metastatic Uveal Melanoma after Radioembolization of Hepatic Metastases

AIM

The aim of this study was to report a case of metastatic uveal melanoma in which radioembolized nodular liver metastases decreased in size while infiltrative sinusoidal metastases progressed, leading to jaundice without obstruction of the biliary ducts.

METHODS

The relevant clinical features, imaging, and histopathologic findings of this case are reviewed.

RESULTS

A 61-year-old Caucasian male with a history of uveal melanoma of the left eye status post plaque brachytherapy developed numerous liver metastases. After progression on systemic therapies, he underwent palliative radioembolization. Despite some radiographic improvement in the liver metastases, he developed hyperbilirubinemia without biliary tract obstruction or signs of liver failure. A biopsy of radiographically normal liver demonstrated extensive sinusoidal infiltration with melanoma.

CONCLUSIONS

Distinct angiographic and histopathologic growth patterns of metastatic uveal melanoma differ in their amenability to radioembolization. Sinusoidal infiltration may lead to hyperbilirubinemia in the absence of overt obstruction or liver failure.

Establishment and Characterization of Orthotopic Mouse Models for Human Uveal Melanoma Hepatic Colonization

Uveal melanoma (UM) is a rare type of melanoma, although it is the most common primary ocular malignant tumor in adults. Nearly one-half the patients with primary UM subsequently develop systemic metastasis, preferentially to the liver. Currently, no treatment is effective for UM hepatic metastasis, and the prognosis is universally poor. The main challenge in designing a treatment strategy for UM hepatic metastasis is the lack of suitable animal models. We developed two orthotopic mouse models for human UM hepatic metastases: direct hepatic implantation model (intrahepatic dissemination model) and splenic-implantation model (hematogenous dissemination model) and investigated the tumorgenesis in the liver. A human UM cell line, established from a hepatic metastasis and nonobese diabetic severe combined immunodeficient γ mice, were used for development of in vivo tumor models. In the direct hepatic implantation model, a localized tumor developed in the liver in all cases and intrahepatic dissemination was subsequently seen in about one-half of cases. However, in the splenic implantation model, multiple hepatic metastases were observed after splenic implantation. Hepatic tumors subsequently seeded intra-abdominal metastasis; however, lung metastases were not seen. These findings are consistent with those observed in human UM hepatic metastases. These orthotopic mouse models offer useful tools to investigate the biological behavior of human UM cells in the liver.

Protein MRI contrast agent with unprecedented metal selectivity and sensitivity for liver cancer imaging

With available MRI techniques, primary and metastatic liver cancers that are associated with high mortality rates and poor treatment responses are only diagnosed at late stages, due to the lack of highly sensitive contrast agents without Gd(3+) toxicity. We have developed a protein contrast agent (ProCA32) that exhibits high stability for Gd(3+) and a 10(11)-fold greater selectivity for Gd(3+) over Zn(2+) compared with existing contrast agents. ProCA32, modified from parvalbumin, possesses high relaxivities (r1/r2: 66.8 mmol(-1)⋅s(-1)/89.2 mmol(-1)⋅s(-1) per particle). Using T1- and T2-weighted, as well as T2/T1 ratio imaging, we have achieved, for the first time (to our knowledge), robust MRI detection of early liver metastases as small as ∼0.24 mm in diameter, much smaller than the current detection limit of 10-20 mm. Furthermore, ProCA32 exhibits appropriate in vivo preference for liver sinusoidal spaces and pharmacokinetics for high-quality imaging. ProCA32 will be invaluable for noninvasive early detection of primary and metastatic liver cancers as well as for monitoring treatment and guiding therapeutic interventions, including drug delivery.

Growth pattern of colorectal liver metastasis as a marker of recurrence risk

Despite improved therapy of advanced colorectal cancer, the median overall survival (OS) is still low. A surgical removal has significantly improved survival, if lesions are entirely removed. The purpose of this retrospective explorative study was to evaluate the prognostic value of histological growth patterns (GP) in chemonaive and patients receiving neo-adjuvant therapy. Two-hundred-fifty-four patients who underwent liver resection of colorectal liver metastases between 2007 and 2011 were included in the study. Clinicopathological data and information on neo-adjuvant treatment were retrieved from patient and pathology records. Histological GP were evaluated and related to recurrence free and OS. Kaplan-Meier curves, log-rank test and Cox regression analysis were used. The 5-year OS was 41.8% (95% CI 33.8-49.8%). Growth pattern evaluation of the largest liver metastasis was possible in 224 cases, with the following distribution: desmoplastic 63 patients (28.1%); pushing 77 patients (34.4%); replacement 28 patients (12.5%); mixed 56 patients (25.0%). The Kaplan-Meier analyses demonstrated that patients resected for liver metastases with desmoplastic growth pattern had a longer recurrence free survival (RFS) than patients resected for non-desmoplastic liver metastases (p=0.05). When patients were stratified according to neo-adjuvant treatment in the multivariate Cox regression model, hazard ratios for RFS compared to desmoplastic were: pushing (HR=1.37, 95% CI 0.93-2.02, p=0.116), replacement (HR=2.16, 95% CI 1.29-3.62, p=0.003) and mixed (HR=1.70, 95% CI 1.12-2.59, p=0.013). This was true for chemonaive patients as well as for patients who received neo-adjuvant treatment.

Efficacy and safety of ipilimumab in patients with pre-treated, uveal melanoma

BACKGROUND

Patients with advanced uveal melanoma have a poor prognosis and limited treatment options. Ipilimumab is approved for pre-treated adult patients with advanced melanoma. However, because previous clinical trials with ipilimumab have excluded patients with uveal melanoma, data in this patient population are limited.

PATIENTS AND METHODS

Pre-treated patients with advanced uveal melanoma received ipilimumab 3 mg/kg through an expanded access programme, every 3 weeks for four doses. Tumour assessments were conducted at baseline and after completion of treatment and patients were monitored throughout for adverse events.

RESULTS

Among 82 assessable patients, 4 (5%) had an immune-related objective response and 24 (29%) had immune-related stable disease lasting ≥3 months for an immune-related disease control rate of 34%. With a median follow-up of 5.6 months, median overall survival (OS) was 6.0 months and median progression-free survival (PFS) was 3.6 months. The 1-year rates of OS and PFS were 31% and 11%, respectively. The safety profile of ipilimumab was similar to that in patients with cutaneous melanoma.

CONCLUSIONS

These data suggest ipilimumab 3 mg/kg is a feasible option in pre-treated patients with metastatic uveal melanoma. Evidence of disease control and a 1-year survival rate of 31% indicate the need for further investigation in randomised, controlled trials to determine the optimal timing and use of ipilimumab in this patient population.

Host pigment epithelium-derived factor (PEDF) prevents progression of liver metastasis in a mouse model of uveal melanoma

Uveal melanoma (UM) has a 30 % 5-year mortality rate, primarily due to liver metastasis. Both angiogenesis and stromagenesis are important mechanisms for the progression of liver metastasis. Pigment epithelium-derived factor (PEDF), an anti-angiogenic and anti-stromagenic protein, is produced by hepatocytes. Exogenous PEDF suppresses metastasis progression; however, the effects of host-produced PEDF on metastasis progression are unknown. We hypothesize that host PEDF inhibits liver metastasis progression through a mechanism involving angiogenesis and stromagenesis. Mouse melanoma cells were injected into the posterior ocular compartment of PEDF-null mice and control mice. After 1 month, the number, size, and mean vascular density (MVD) of liver metastases were determined. The stromal component of hepatic stellate cells (HSCs) and the type III collagen they produce was evaluated by immunohistochemistry. Host PEDF inhibited the total area of liver metastasis and the frequency of macrometastases (diameter >200 μm) but did not affect the total number of metastases. Mice expressing PEDF exhibited significantly lower MVD and less type III collagen production in metastases. An increase in activated HSCs was seen in the absence of PEDF, but this result was not statistically significant. In conclusion, host PEDF inhibits the progression of hepatic metastases in a mouse model of UM, and loss of PEDF is accompanied by an increase in tumor blood vessel density and type III collagen.