Prognostic value of TERT promoter mutations in conjunctival melanomas in addition to clinicopathological features

Mucosal Melanoma: Review from a Pathologist Point of View

Mucosal melanomas are rare malignant tumors arising from the epithelia lining the inner mucosal surfaces of the body. Unlike cutaneous melanoma, we have a limited understanding of mucosal melanomas is currently limited. Mucosal melanomas are characterized by genetic alterations quite distinct from cutaneous melanomas; however, their causative and promoting factors are unknown. These melanomas are characteristically diagnosed at a later stage due to their occult locations, leading to a worse prognosis. Dedicated staging systems for mucosal melanomas exist only for sinonasal and conjunctival melanomas. Therefore, risk stratification of patients with mucosal melanomas, particularly those arising from the anogenital area, is challenging. Recent studies have shown that minor modifications of the AJCC 8th Edition cutaneous melanoma staging system can group patients fairly robustly; however, the proposed T-categorization systems have yet to be validated in larger cohorts. We summarize the demographic, clinical, histopathologic, and molecular features of common subtypes of mucosal melanomas and highlight the outstanding needs in this field.

Advances in conjunctival melanoma: clinical features, diagnostic modalities, staging, genetic markers, and management

Conjunctival melanoma, a rare malignancy of the ocular surface, is increasing in incidence. When small, straightforward excision with "no touch" surgery and cryotherapy at an experienced centre can provide excellent outcomes. When advanced, management is more complex and highly individualized. The risk of metastatic disease from conjunctival melanoma is as high as 30% and depends on tumour origin, American Joint Committee on Cancer (AJCC) classification, biomarkers, and perhaps most important, management technique. Metastatic disease can result in melanoma-associated death. Therefore, early detection and prompt directed treatment at an experienced centre are important for protection from metastasis. In this review, we provide an update on conjunctival melanoma clinical features, diagnostic modalities, AJCC staging, genetic markers, and the most critical, controlled management with minimization of tumour seeding. We detail the new era of characterization of conjunctival melanoma with molecular biomarkers that predict melanoma prognosis. This could lead to precision medicine with targeted approaches to specific mutations that improve patient survival. As we work together, the field of conjunctival melanoma is moving forward.

Advances in Molecular Understanding of Ocular Adnexal Disease

The goal of this Special Issue is to provide comprehensive molecular biological data that aims to elucidate the molecular and epigenetic mechanisms operable in diseases of the ocular adnexa [...].

Genetic Aspects of Conjunctival Melanoma: A Review

Conjunctival melanoma (CM) is a rare but aggressive cancer. Over the past decade, molecular studies using rapidly advancing technologies have increasingly improved our understanding of CM genetics. CMs are mainly characterized by dysregulated MAPK and PI3K/AKT/mTOR pathways, driven by commonly mutated (BRAF, NRAS, NF1) or less commonly mutated (KIT, PTEN) genes. Another group of genes frequently mutated in CMs include TERT and ATRX, with known roles in telomere maintenance and chromatin remodeling/epigenetic regulation. Uveal melanoma-related genes (BAP1, SF3B1, GNAQ/11) can also be mutated in CMs, albeit infrequently. Additional CM-related mutated genes have increasingly been identified using more comprehensive genetic analyses, awaiting further confirmation in additional/larger studies. As a tumor arising in a partly sun-exposed mucosal tissue, CM exhibits a distinct genomic profile, including the frequent presence of an ultraviolet (UV) signature (and high mutational load) and also the common occurrence of large structural variations (distributed across the genome) in addition to specific gene mutations. The knowledge gained from CM genetic studies to date has led to new therapeutic avenues, including the use of targeted and/or immuno-therapies with promising outcomes in several cases. Accordingly, the implementation of tumor genetic testing into the routine clinical care of CM patients holds promise to further improve and personalize their treatments. Likewise, a growing knowledge of poor prognosis-associated genetic changes in CMs (NRAS, TERT, and uveal melanoma signature mutations and chromosome 10q deletions) may ultimately guide future strategies for prognostic testing to further improve clinical outcomes (by tailoring surveillance and considering prophylactic treatments in patients with high-risk primary tumors).

ATRX Loss in the Development and Prognosis of Conjunctival Melanoma

Metastatic disease is linked to TERT promoter mutations in conjunctival melanomas (CM). Both TERT promoter and ATRX mutations are associated with faulty telomere maintenance. This study aimed to determine the prognostic value of ATRX loss in conjunctival melanocytic lesions. Eighty-six conjunctival melanocytic lesions from the Rotterdam Ocular Melanoma Study group were collected. ATRX status and TERT promoter status were determined using immunohistochemical staining and molecular diagnostics, respectively. None of the nevi (n = 16) and primary acquired melanosis (PAM) without atypia (n = 6) showed ATRX loss. ATRX loss was found in 2/5 PAM with atypia without CM and in 8/59 CM. No cases with a TERT promoter mutation (n = 26) showed ATRX loss. Eight/eleven metastatic CM harbored a TERT promoter mutation, two other metastatic CM showed ATRX loss and one metastatic case showed no TERT promoter/ATRX alterations. In conclusion ATRX loss and TERT promoter mutations are only found in (pre)malignant conjunctival melanocytic lesions, with most metastatic cases harboring one of these alterations, suggesting that both alterations are associated with adverse behavior. Similar to TERT promoter mutations, ATRX loss may be used as a diagnostic tool in determining whether a conjunctival melanocytic lesion is prone to having an adverse course.

A rare case of a long-standing, extensive, invasive conjunctival melanoma without systemic metastasis

Conjunctival melanoma is an uncommon and malignant tumor of the ocular surface with the propensity for metastasis and death. Despite the grim outlook, the factors predicting poor prognosis are slowly being uncovered given the rarity of the disease. Here, we present a rare and surprising case of a long standing, extensive, and invasive conjunctival melanoma that, despite multiple factors predicting a poor prognosis, had no systemic metastatic disease. We hope that by reviewing in depth the various factors that may explain our patient's unusual course of illness we can add to our growing understanding of conjunctival melanoma.

New Therapeutic Approaches for Conjunctival Melanoma-What We Know So Far and Where Therapy Is Potentially Heading: Focus on Lymphatic Vessels and Dendritic Cells

Conjunctival melanoma (CM) accounts for 5% of all ocular melanomas and arises from malignantly transformed melanocytes in the conjunctival epithelium. Current therapies using surgical excision in combination with chemo- or cryotherapy still have high rates for recurrences and metastatic disease. Lately, novel signal transduction-targeted and immune checkpoint inhibitors like cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, programmed cell death protein-1 (PD-1) receptor inhibitors, BRAF- or MEK-inhibitors for systemic treatment of melanoma have improved the outcome even for unresectable cutaneous melanoma, improving patient survival dramatically. The use of these therapies is now also recommended for CM; however, the immunological background of CM is barely known, underlining the need for research to better understand the immunological basics when treating CM patients with immunomodulatory therapies. Immune checkpoint inhibitors activate tumor defense by interrupting inhibitory interactions between tumor cells and T lymphocytes at the so-called checkpoints. The tumor cells exploit these inhibitory targets on T-cells that are usually used by dendritic cells (DCs). DCs are antigen-presenting cells at the forefront of immune response induction. They contribute to immune tolerance and immune defense but in the case of tumor development, immune tolerance is often prevalent. Enhancing the immune response via DCs, interfering with the lymphatic pathways during immune cell migration and tumor development and specifically targeting tumor cells is a major therapeutic opportunity for many tumor entities including CM. This review summarizes the current knowledge on the function of lymphatic vessels in tumor growth and immune cell transport and continues to compare DC subsets in CM with related melanomas, such as cutaneous melanoma and mucosal melanoma.

Molecular Genetics of Conjunctival Melanoma and Prognostic Value of TERT Promoter Mutation Analysis

The aim of this study was exploration of the genetic background of conjunctival melanoma (CM) and correlation with recurrent and metastatic disease. Twenty-eight CM from the Rotterdam Ocular Melanoma Study group were collected and DNA was isolated from the formalin-fixed paraffin embedded tissue. Targeted next-generation sequencing was performed using a panel covering GNAQ, GNA11, EIF1AX, BAP1, BRAF, NRAS, c-KIT, PTEN, SF3B1, and TERT genes. Recurrences and metastasis were present in eight (29%) and nine (32%) CM cases, respectively. TERT promoter mutations were most common (54%), but BRAF (46%), NRAS (21%), BAP1 (18%), PTEN (14%), c-KIT (7%), and SF3B1 (4%) mutations were also observed. No mutations in GNAQ, GNA11, and EIF1AX were found. None of the mutations was significantly associated with recurrent disease. Presence of a TERT promoter mutation was associated with metastatic disease (p-value = 0.008). Based on our molecular findings, CM comprises a separate entity within melanoma, although there are overlapping molecular features with uveal melanoma, such as the presence of BAP1 and SF3B1 mutations. This warrants careful interpretation of molecular data, in the light of clinical findings. About three quarter of CM contain drug-targetable mutations, and TERT promoter mutations are correlated to metastatic disease in CM.

Genetics of Ocular Melanoma: Insights into Genetics, Inheritance and Testing

Ocular melanoma consists of posterior uveal melanoma, iris melanoma and conjunctival melanoma. These malignancies derive from melanocytes in the uveal tract or conjunctiva. The genetic profiles of these different entities differ from each other. In uveal melanoma, GNAQ and GNA11 gene mutations are frequently found and prognosis is based on mutation status of BAP1, SF3B1 and EIF1AX genes. Iris melanoma, also originating from the uvea, has similarities to the genetic makeups of both posterior uveal melanoma (UM) and conjunctival melanoma since mutations in GNAQ and GNA11 are less common and genes involved in conjunctival melanoma such as BRAF have been described. The genetic spectrum of conjunctival melanoma, however, includes frequent mutations in the BRAF, NRAS and TERT promoter genes, which are found in cutaneous melanoma as well. The BRAF status of the tumor is not correlated to prognosis, whereas the TERT promoter gene mutations are. Clinical presentation, histopathological characteristics and copy number alterations are associated with survival in ocular melanoma. Tissue material is needed to classify ocular melanoma in the different subgroups, which creates a need for the use of noninvasive techniques to prognosticate patients who underwent eye preserving treatment.