The role of UV-radiation in the development of conjunctival malignant melanoma

A UV-related risk analysis in ophthalmic malignancies: Increased UV exposure may cause ocular malignancies

Purpose

To explore the role of ultraviolet radiation (UVR) in the occurrence and development of various ocular malignancies.

Methods

In this article, we retrieved ocular malignancy data from the Global Cancer Observatory (GCO) and performed correlation analysis with the global UV index and sunshine duration. We searched for associated studies using the following databases: Embase, Pubmed, Cochrane Library, and Google Scholar. We conducted the literature by searching the Mesh terms denoting an exposure of interest ("UV radiation", "ultraviolet rays", and "ocular malignancies", All studies included are published until December 30, 2023 without language restrictions.

Results

The mechanisms and epidemiological statistics of UVR on the onset and progression of eyelid malignancies are the most studied and clear. The role of UVR in conjunctival melanoma is similar to that in eyelid melanoma. The relationship between uveal melanoma and UVR is controversial, however, it may have at least a certain impact on its prognosis. UVR causes ocular surface squamous neoplasia by further activating HPV infection.

Conclusions

UVR is a decisive risk factor for ocular malignancies, but the incidence of ultraviolet-induced tumors is also affected by many other factors. A correct and comprehensive understanding of the mechanisms of UVR in the pathogenesis of ocular malignant tumors can provide patients with more effective and selective immune regulation strategies.

Validation of an Ultraviolet Light Response Gene Signature for Predicting Prognosis in Patients with Uveal Melanoma

Uveal melanoma (UVM) is a highly aggressive ocular cancer with limited therapeutic options and poor prognosis particularly for patients with liver metastasis. As such, the identification of new prognostic biomarkers is critical for developing effective treatment strategies. In this study, we aimed to investigate the potential of an ultraviolet light response gene signature to predict the prognosis of UVM patients. Our approach involved the development of a prognostic model based on genes associated with the cellular response to UV light. By employing this model, we generated risk scores to stratify patients into high- and low-risk groups. Furthermore, we conducted differential expression analysis between these two groups and explored the estimation of immune infiltration. To validate our findings, we applied our methodology to an independent UVM cohort. Through our study, we introduced a novel survival prediction tool and shed light on the underlying cellular processes within UVM tumors, emphasizing the involvement of immune subsets in tumor progression.

Conjunctival melanoma: New insights in tumour genetics and immunology, leading to new therapeutic options

Recent developments in oncology have led to a better molecular and cellular understanding of cancer, and the introduction of novel therapies. Conjunctival melanoma (CoM) is a rare but potentially devastating disease. A better understanding of CoM, leading to the development of novel therapies, is urgently needed. CoM is characterized by mutations that have also been identified in cutaneous melanoma, e.g. in BRAF, NRAS and TERT. These mutations are distinct from the mutations found in uveal melanoma (UM), affecting genes such as GNAQ, GNA11, and BAP1. Targeted therapies that are successful in cutaneous melanoma may therefore be useful in CoM. A recent breakthrough in the treatment of patients with metastatic cutaneous melanoma was the development of immunotherapy. While immunotherapy is currently sparsely effective in intraocular tumours such as UM, the similarities between CoM and cutaneous melanoma (including in their immunological tumour micro environment) provide hope for the application of immunotherapy in CoM, and preliminary clinical data are indeed emerging to support this use. This review aims to provide a comprehensive overview of the current knowledge regarding CoM, with a focus on the genetic and immunologic understanding. We elaborate on the distinct position of CoM in contrast to other types of melanoma, and explain how new insights in the pathophysiology of this disease guide the development of new, personalized, treatments.

Genetic drivers of non-cutaneous melanomas: Challenges and opportunities in a heterogeneous landscape

Non-cutaneous melanomas most frequently involve the uveal tract and mucosal membranes, including the conjunctiva. In contrast to cutaneous melanoma, they often present at an advanced clinical stage, are associated with worse clinical outcomes and show poorer responses to immunotherapy. The mutational load within most non-cutaneous melanomas reflects their lower ultraviolet light (UV) exposure. The genetic drivers within non-cutaneous melanomas are heterogeneous. Within ocular melanomas, posterior uveal tract melanomas typically harbour one of two distinct, sets of driver mutations and alterations of clinical and biological significance. In contrast to posterior uveal tract melanomas, anterior uveal tract melanomas of the iris and conjunctival melanomas frequently carry both a higher mutational burden and specific mutations linked with UV exposure. The genetic drivers in iris melanomas more closely resemble those of the posterior uveal tract, whereas conjunctival melanomas harbour similar genetic driver mutations to cutaneous melanomas. Mucosal melanomas occur in sun-shielded sites including sinonasal and oral cavities, nasopharynx, oesophagus, genitalia, anus and rectum, and their mutational landscape is frequently associated with a dominant process of spontaneous deamination and infrequent presence of UV mutation signatures. Genetic drivers of mucosal melanomas are diverse and vary with anatomic location. Further understanding of the causes of already identified recurrent molecular events in non-cutaneous melanomas, identification of additional drivers in specific subtypes, integrative multi-omics analyses and analysis of the tumor immune microenvironment will expand knowledge in this field. Furthermore, such data will likely uncover new therapeutic strategies which will lead to improved clinical outcomes in non-cutaneous melanoma patients.

Conjunctival melanoma copy number alterations and correlation with mutation status, tumor features, and clinical outcome

Relatively little is known about the genetic aberrations of conjunctival melanomas (CoM) and their correlation with clinical and histomorphological features as well as prognosis. The aim of this large collaborative multicenter study was to determine potential key biomarkers for metastatic risk and any druggable targets for high metastatic risk CoM. Using Affymetrix single nucleotide polymorphism genotyping arrays on 59 CoM, we detected frequent amplifications on chromosome (chr) 6p and deletions on 7q, and characterized mutation‐specific copy number alterations. Deletions on chr 10q11.21‐26.2, a region harboring the tumor suppressor genes, PDCD4, SUFU, NEURL1, PTEN, RASSF4, DMBT1, and C10orf90 and C10orf99, significantly correlated with metastasis (Fisher's exact, p ≤ 0.04), lymphatic invasion (Fisher's exact, p ≤ 0.02), increasing tumor thickness (Mann–Whitney, p ≤ 0.02), and BRAF mutation (Fisher's exact, p ≤ 0.05). This enhanced insight into CoM biology is a step toward identifying patients at risk of metastasis and potential therapeutic targets for systemic disease.

SDHD promoter mutations are rare events in cutaneous melanomas but SDHD protein expression is downregulated in advanced cutaneous melanoma

BACKGROUND

SDHD promoter mutations were reported in 4-10% of cutaneous melanomas. The advanced clinico-pathological and patient survival association with SDHD mutation and/or expression in cutaneous melanoma remains controversial.

OBJECTIVES

To evaluate the presence of SDHD promoter mutations and SDHD protein expression in a melanoma series and its possible association with prognosis and survival of the patients.

METHODS

We assessed SDHD promoter status in cutaneous melanomas (CM), ocular melanomas (OM) and melanoma cell lines, and the expression of SDHD protein by immunohistochemistry in CM and OM, and by western blot in melanoma cell lines. We explored the putative association between SDHD protein expression and clinico-pathological and prognostic parameters of melanoma.

RESULTS

We detected 2% of SDHD promoter mutations in CM, but none in OM and cell lines. SDHD protein expression was present in all CM, in OM and in all CM and OM derived cell lines analysed. A significant association between lower SDHD mean protein expression and presence of ulceration and higher pT stage was found.

CONCLUSIONS

SDHD promoter mutation seems to be a rare event in CM but SDHD lower expression might associate with worst prognostic features in CM.

Conjunctival malignant melanoma in Denmark: epidemiology, treatment and prognosis with special emphasis on tumorigenesis and genetic profile

Conjunctival malignant melanoma is a rare disease associated with considerable mortality. Most published data have been based on case reports or series of referred patients. In addition, very little is known about the genetic and epigenetic profile of conjunctival melanoma and the resemblance to uveal, cutaneous and mucosal melanoma. The aim was to determine the incidence rate of conjunctival melanoma, and to relate clinicopathological features and treatment to prognosis. A further aim was to determine the prevalence of BRAF mutations in conjunctival melanoma, to determine whether BRAF mutations are early events in pathogenesis, and relate clinicopathological features and prognosis to BRAF-mutation status. Finally, we wanted to identify tumour-specific and prognostic microRNAs in conjunctival melanoma, and to compare these with the microRNA expression of other melanoma subtypes. In order to investigate these rare tumours, we studied all the conjunctival melanomas that had been surgically removed in Denmark over a period of 52 years (1960-2012). Tissue samples, clinical files, pathology reports and follow-up data were collected and re-evaluated. Using droplet digital polymerase chain reaction and immunohistochemistry, we investigated BRAF mutations; and using microRNA expression profiling, we investigated differentially expressed microRNAs. The overall incidence of conjunctival melanoma was 0.5/1 000 000/year, and it increased in Denmark over 52 years. The increase was mainly caused by an increase in older patients (>65 years) and bulbar lesions. Clinicopathological features significantly associated with a poor prognosis were extrabulbar location, involvement of adjacent tissue structures, tumour thickness exceeding 2 mm and local tumour recurrence. Patients undergoing incisional biopsy and/or treatment involving excision without adjuvant therapy fared worse than patients treated with excision and any type of adjuvant treatment. We found that 35% (39/110) of conjunctival melanomas were BRAF-mutated, and the incidence of BRAF mutations was constant over time. BRAF-mutation status corresponded in conjunctival melanoma and paired premalignant lesions. BRAF mutations were more frequent in males, in young patients, and in tumours with a sun-exposed tumour location (bulbar conjunctiva or caruncle), with a mixed or non-pigmented colour, with absence of primary acquired melanosis, and with origin in a nevus. Immunohistochemistry was able to accurately detect BRAF V600E mutations. In univariate analysis, distant metastatic disease was associated with BRAF mutations. No prognostic associations with BRAF mutations were identified in multivariate analyses. MicroRNA expression analysis revealed 25 tumour-specific microRNAs in conjunctival melanoma. Five possibly oncogenic miRNAs (miR-20b-5p, miR-146b-5p, miR-146a-5p, miR-506-3p and miR-509-3p) were up-regulated. Seven microRNAs (miR-30d-5p, miR-138-5p, miR-146a-5p, miR-500a-5p, miR-501-3p, miR-501-5p and miR-502-3p) were significantly and simultaneously up-regulated in both stage T1 and stage T2 tumours, and were associated with increased tumour thickness. The expression of the 25 tumour-specific microRNAs did not differ significantly between conjunctival melanoma and oral or nasal mucosal melanoma. In conclusion, the incidence of conjunctival melanoma increased in the Danish population from 1960 to 2012. From our findings of a distinct pattern of BRAF mutations and differentially expressed microRNAs, it is evident that conjunctival melanoma is closely related to cutaneous and other mucosal melanomas and bears less resemblance to uveal melanomas. This means that conjunctival melanoma patients may benefit from therapies that are effective for cutaneous and mucosal melanoma. Additionally, the identification of several up-regulated microRNAs may prove to be useful as prognostic or therapeutic targets in conjunctival melanoma.

Conjunctival melanomas harbor BRAF and NRAS mutations and copy number changes similar to cutaneous and mucosal melanomas

PURPOSE

Conjunctival melanoma is a rare but potentially deadly tumor of the eye. Despite effective local therapies, recurrence and metastasis remain frequent. Once the tumor has metastasized, treatment options are limited and the prognosis is poor. To date, little is known of the genetic alterations in conjunctival melanomas.

EXPERIMENTAL DESIGN

We conducted genetic analysis of 78 conjunctival melanomas, to our knowledge the largest cohort reported to date. An oncogene hotspot array was run on 38 samples, screening for a panel of known cancer-relevant mutations. Thirty tumors were analyzed for genome-wide copy number alterations (CNA) using array-based comparative genomic hybridization. Sanger sequencing of selected target mutations was conducted in all samples.

RESULTS

BRAF mutations were identified in 23 of 78 (29%) tumors. NRAS mutations, previously not recognized as relevant in conjunctival melanoma, were detected in 14 of 78 (18%) tumors. We found CNAs affecting various chromosomes distributed across the genome in a pattern reminiscent of cutaneous and mucosal melanoma but differing markedly from uveal melanoma.

CONCLUSIONS

The presence of NRAS or BRAF mutations in a mutually exclusive pattern in roughly half (47%) of conjunctival melanomas and the pattern of CNAs argue for conjunctival melanoma being closely related to cutaneous and mucosal melanoma but entirely distinct from uveal melanoma. Patients with metastatic conjunctival melanoma should be considered for therapeutic modalities available for metastatic cutaneous and mucosal melanoma including clinical trials of novel agents.

Melanocytic Lesions of the Conjunctiva

Context—Melanocytic proliferations are among the most common neoplasms of the conjunctiva. They often represent challenging lesions for pathologists unfamiliar with unique histologic features of melanocytic proliferations in this location and with nomenclature used by ophthalmologists.

Objective—To comprehensively review clinical aspects, pathologic features, and management of melanocytic proliferations of the conjunctiva.

Data Sources—Review of the literature and personal experience of the authors.

Conclusions—Classification, state of the art, and practical aspects of pathology of melanocytic proliferations of the conjunctiva are discussed.

Evaluation of the mTOR pathway in ocular (uvea and conjunctiva) melanoma

Ocular melanoma is the most common eye malignancy in adults. It usually arises in the uvea, mostly in the choroid and less frequently in the conjunctiva. There is no curative therapy available when it becomes metastatic. The etiopathogenesis of uvea and conjunctiva melanomas is still poorly understood. The mammalian target of rapamycin (mTOR) pathway is involved in many biological processes and has been implicated in the development of cutaneous melanoma tumours. The mTOR pathway is an important target for anticancer drug development, and an inhibitor of this pathway has already been approved for use in humans to treat advanced renal cell carcinoma. The aim of this study was to evaluate the contribution of the mTOR pathway in uvea and conjunctiva melanomas. We analysed specific mTOR pathway effectors using immunohistochemical analysis of 30 uvea and eight conjunctiva melanoma samples. We assessed the association with prognostic clinical-pathological features, and performed mutational analysis on the BRAF and NRAS genes. None of the cases had mutations in either BRAF or NRAS. Expression of phospho-AKT Thr308 was associated with metastatic uvea melanomas. In conjunctiva melanomas, overactivation of the mTOR pathway, as confirmed by high phospho-AKT Ser473 and Thr308, S6 and p4EBP1 Thr37/46 levels, was associated with adverse prognostic parameters (mitotic index and tumour thickness). Conjunctiva melanomas displayed high expression of phospho-mTOR effectors in contrast with uvea melanomas, in which PTEN seemed to downregulate the mTOR pathway. Characterizing the expression of PTEN, AKT and pS6 Ser235/236 might be a useful predictive tool for deciding whether to use mTOR inhibitors to treat conjunctiva melanomas.

Main roads to melanoma

The characterization of the molecular mechanisms involved in development and progression of melanoma could be helpful to identify the molecular profiles underlying aggressiveness, clinical behavior, and response to therapy as well as to better classify the subsets of melanoma patients with different prognosis and/or clinical outcome. Actually, some aspects regarding the main molecular changes responsible for the onset as well as the progression of melanoma toward a more aggressive phenotype have been described. Genes and molecules which control either cell proliferation, apoptosis, or cell senescence have been implicated. Here we provided an overview of the main molecular changes underlying the pathogenesis of melanoma. All evidence clearly indicates the existence of a complex molecular machinery that provides checks and balances in normal melanocytes. Progression from normal melanocytes to malignant metastatic cells in melanoma patients is the result of a combination of down- or up-regulation of various effectors acting on different molecular pathways.

The role of B-RAF in melanoma

Melanoma is a form of skin cancer that has a poor prognosis and which is on the rise in Western populations. If detected early, it is easily treated by surgical excision. However, once melanoma metastasises it is notoriously resistant to existing therapies and for many patients the outlook is dismal. Thus a full description of melanoma etiology and a full understanding of the genetic lesions that underlie this disease is required to allow us to develop new and effective therapeutic strategies for its treatment. RAF proteins are a family of serine/threonine-specific protein kinases that form part of a signalling module that regulates cell proliferation, differentiation and survival. In mammals there are three isoforms, A-RAF, B-RAF and C-RAF, and recently it was shown that the B-RAF isoform is mutated in a high proportion of melanomas. In light of these exciting findings, we review what we have learned about B-RAF and its role in cutaneous melanoma.

Exon 15 BRAF mutations are uncommon in melanomas arising in nonsun-exposed sites

PURPOSE

An activating point mutation of the BRAF oncogene has been identified in a high proportion of cutaneous nevi and cutaneous melanomas, but its frequency in melanomas arising from the mucosa of head and neck is unknown.

EXPERIMENTAL DESIGN

We tested 17 malignant mucosal melanomas of the head and neck for the thymine (T)-->adenine (A) missense mutation at nucleotide 1796 in the BRAF gene using direct sequencing and a newly developed assay that uses a novel primer extension method (Mutector assay). We also tested 21 cutaneous melanomas, including 13 arising from sun-exposed sites and 8 from a nonsun-exposed site, the vulvar skin.

RESULTS

The 1796T-->A mutation was detected in only 1 (6%) of the sinonasal melanomas. As for cutaneous melanomas, a BRAF mutation was detected in 8 (62%) of the tumors arising in sun-exposed sites but in none (0%) of vulvar melanomas.

CONCLUSIONS

In contrast to cutaneous melanomas arising in sun-exposed sites, mucosal melanomas of the head and neck do not frequently harbor an activating mutation of BRAF. This finding additionally supports the view that the various subtypes of melanoma are not equivalent and that distinct genetic alterations may underlie well recognized differences in risk factors and behavioral patterns. Accordingly, patients with melanomas should not be collectively regarded as a uniform group as new strategies are developed that target specific genetic alterations.

Detection of point mutations at codon 12 of KI-ras in ophthalmic pterygia

AIMS

Ophthalmic pterygium is a potentially vision-threatening lesion of unknown etiology, related to an exposure to solar light. Mutations to the ras genes are frequently observed in lesions related to an exposure to solar light. The present study aims at screening pterygia for mutations at codons 12 and 13 of the ras genes.

METHODS

In all, 50 pterygia were examined, together with respective blood samples and specimens of normal conjunctiva. A PCR reaction was performed to amplify sequences containing codons 12 and 13 of Ki-ras, H-ras, and N-ras. An RFLP analysis was then performed to detect point mutations at codon 12. The mutational status at codons 12 and 13 was further explored with sequencing of PCR products.

RESULTS

RFLP analysis revealed Ki-ras mutations at codon 12 in five (10%) of pterygia, whereas H-ras or N-ras mutations were not observed. Sequencing confirmed Ki-ras mutations at codon 12 and revealed absence of mutations at codon 13. The presence of Ki-ras mutations was significantly correlated with postoperative recurrence (P=0.02) and young age (P=0.04). Mutations were not observed in specimens of blood or normal conjunctiva for any of the genes examined.

CONCLUSIONS

The absence of N-ras mutations is in agreement with previous reports concerning mucosal lesions. The detection of Ki-ras mutations and the association with postoperative recurrence implies a possible role of Ki-ras in the clinical profile of pterygium. The mechanism of Ki-ras mutations is unclear and could be independent of the action of UV light.

Clinical aspects of conjunctival melanoma

Conjunctival melanoma is a rare but important condition encountered in ophthalmology. This paper reviews conjunctival melanoma as a clinical entity, with particular emphasis on differential diagnosis, management and prognostic factors. Relevant references were located through a comprehensive search of articles published between 1980 and early 2001 on Medline, using both the WinSpirs and PubMed platforms. The references of these articles were then checked for further articles of relevance. The condition is uncommon and its presentation variable; therefore, relevant studies were found to suffer from small numbers of subjects. This may be the cause of the confusion that still surrounds the condition and its management.