Activating mutations of the GNAQ gene: a frequent event in primary melanocytic neoplasms of the central nervous system

Primary leptomeningeal melanocytic neoplasms: A clinicopathologic, immunohistochemical, and molecular study of 12 cases

This study investigated the clinicopathological, immunohistochemical, and molecular features of primary leptomeningeal melanocytic neoplasms (LMNs). Twelve LMN cases were retrospectively reviewed. We performed Fluorescence in-situ hybridization (including a 4-probe FISH assay with CDKN2A and MYC assay) and Next-Generation sequencing analyses on available cases. Histologically, 2 tumours were classified as melanocytomas (MC), 2 as intermediate-grade melanocytomas (IMC), and 8 as leptomeningeal melanomas (LMM). Two rare cases of LMM were associated with large plaque-like blue nevus. One MC case was associated with Ota. Ten cases (83.3%) showed melanocytic cells with benign features diffusely proliferating within the meninges. The Ki-67 in three categories differed (MC 0-1%, IMC 0-3%, LMM 3-10%). 57.1% of LMM cases (4/7) were positive for FISH. Nine of 10 tumours harboured activating hotspot mutations in GNAQ, GNA11, or PLCB4. Additional mutations of EIF1AX, SF3B1, or BAP1 were found in 40%, 30%, and 10% of tumours, respectively. During the follow-up (median = 43 months), 5 LMM patients experienced recurrence and/or metastasis, 3 of them died of the disease and the other 2 are alive with the tumour. Our study is by far the first cohort of LMN cases tested by FISH. In addition to morphological indicators including necrosis and mitotic figures, using a combination of Ki-67 and FISH helps to differentiate between IMC and LMM, especially in LMM cases with less pleomorphic features. SF3B1 mutation is first described in 2 cases of plaque-type blue nevus associated with LMM. Patients with SF3B1 mutation might be related to poor prognosis in LMN.

Extradural spinal melanoma: is it primary or metastatic? A case report with a brief review of literature

Melanocytic lesions involving the central nervous system are extremely rare and pose a diagnostic challenge owing melanoma being the third most common malignancy metastasizing to the spine. Morphology and immunohistochemistry are identical in both primary and secondary cases, and hence may not help in rendering a final diagnosis. Molecular alterations involving melanomas of the spine and melanomas elsewhere are distinct and help establish the appropriate diagnosis. We report an interesting case where molecular profiling of the tumor tissue helped render the final diagnosis.

Missense mutation of NRAS is associated with malignant progression in neurocutaneous melanosis

Neurocutaneous melanosis (NCM) is a rare congenital neurocutaneous syndrome characterized by congenital melanocytic nevus of skin and abnormal proliferation of leptomeningeal melanocytes. Early acquisition of post-zygotic somatic mutations has been postulated to underlie the pathogenesis of NCM. The pathogenesis of NCM remains to be fully elucidated, and treatment options have not been established. Here, we report for the first time, multiregional genomic analyses in a 3-year-old autopsied girl with leptomeningeal melanomatosis associated with NCM, in which a ventriculo-peritoneal (VP) shunt was inserted for the treatment of hydrocephalus. The patient expired six months after the onset due to respiratory failure caused by abdominal dissemination via VP shunt. We performed multiregional exome sequencing to identify genomic differences among brain and abdominal tumors, nevus, and normal tissues. A total of 87 somatic mutations were found in 71 genes, with a significantly large number of gene mutations found in the tumor site. The genetic alterations detected in the nevus were only few and not shared with other sites. Three mutations, namely GNAQ R183Q, S1PR3 G89S and NRAS G12V, considered pathogenic, were found, although S1PR3 mutations have not been previously reported in melanocytic tumors. GNAQ and S1PR3 mutations were shared in both tumor and normal sites. Moreover, the mutant allele frequencies of the two mutations were markedly higher in tumor sites than in normal sites, with copy-neutral loss-of-heterozygosity (CN-LOH) occurring in tumor. NRAS mutation was found only in the abdominal tumor and was thought to be responsible for malignant progression in the present case. Multiregional comprehensive genetic analysis may lead to discovering novel driver mutations associated with tumorigenesis and targeted therapy.

Brazilian Society of Otology task force - Vestibular Schwannoma ‒ evaluation and treatment

OBJECTIVE

To review the literature on the diagnosis and treatment of vestibular schwannoma.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on vestibular schwannoma were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Diagnosis - audiologic, electrophysiologic tests, and imaging; (2) Treatment - wait and scan protocols, surgery, radiosurgery/radiotherapy, and systemic therapy.

CONCLUSIONS

Decision making in VS treatment has become more challenging. MRI can diagnose increasingly smaller tumors, which has disastrous consequences for the patients and their families. It is important to develop an individualized approach for each case, which highly depends on the experience of each surgical team.

[Histological and molecular characteristics of tumours of the peripheral nervous system]

Tumours of the peripheral nervous system occur sporadically in adults and except for a minority of entities, these tumours are usually benign. The most common are nerve sheath tumours. Because these tumours grow in direct proximity or even invade peripheral nerve bundles, they can lead to severe pain and motion deficits. From the neurosurgical perspective these tumours are technically challenging, and especially for tumours with an invasive growth pattern complete resection may not be possible. Peripheral nervous system tumours that are associated with tumour syndromes such as neurofibromatosis type 1 and 2 or schwannomatosis are a particular clinical challenge. The goal of the current article is to present histological and molecular characteristics of peripheral nervous system tumours. Furthermore, future targeted therapy strategies are presented.

Melanocytic naevi, melanocytomas and emerging concepts

With the elucidation of the genetics of melanocytic tumours, new concepts have emerged. An important one is the identification of 'intermediate' melanocytic tumours, those with genetic progression events beyond those of melanocytic naevi but that are not fully malignant. Thus, melanocytic tumours exist on a genetic spectrum that likely corresponds to biological behaviour. There are multiple pathways to melanoma development with different initiating events and characteristic benign melanocytic neoplasms and the precise placement of tumours on these pathways remains to be established and the corresponding risks of progression quantified. In this review, I discuss the classification of melanocytic naevi based on clinical, histopathological and genetic features, as well as the concept of melanocytomas with discussion of specific recognisable subtypes.

Imaging and pathological diagnosis of primary intracranial malignant melanoma: A case report and literature review

RATIONALE

Primary intracranial malignant melanoma (PIMM) is a rare malignant tumor that lacks specific clinical manifestations. Preoperative diagnosis is difficult to differentiate from meningiomas on computed tomography (CT) scans. Magnetic resonance imaging (MRI) usually shows typical characteristics with high signal intensity on T1WI and low signal intensity on T2WI. PIMM is highly invasive, insensitive to chemoradiotherapy, and has a poor prognosis.

PATIENT CONCERNS

A 27-year-old woman was admitted to the hospital with a headache for 10 days. She did not experience nausea, vomiting, dizziness, or any other discomfort. A computerized tomography (CT) scan demonstrated a high-density mass in the left cerebellum with patchy calcification at the posterior edge, and heterogeneous enhancement was observed on a contrast-enhanced scan. MRI revealed typical characteristics of high signal intensity on T1WI and low signal intensity on T2WI. The signal characteristics of FLAIR were similar to those of T2WI, and diffusion-weighted imaging (DWI) sequence showed limited diffusion of the tumor. Magnetic resonance spectroscopy revealed increased choline (Cho) and decreased creatine (Cr) and N-acetyl aspartate (Naa) in the tumor.

INTERVENTIONS

The patient underwent tumor resection and postoperative chemoradiotherapy and immunotherapy.

PATHOLOGICAL DIAGNOSIS

Histological and Immunohistochemistry (IHC) tests confirmed the diagnosis of PIMM. In addition, genetic testing revealed GNAQ gene variation.

OUTCOMES

No recurrence or complications were observed during the follow-up for 6 months.

LESSONS

PIMM is rare, and its pathological diagnosis should be closely combined with clinical and medical history. GNAQ is a common variant of PIMM and is expected to be a therapeutic target.

An Update of G-Protein-Coupled Receptor Signaling and Its Deregulation in Gastric Carcinogenesis

G-protein-coupled receptors (GPCRs) belong to a cell surface receptor superfamily responding to a wide range of external signals. The binding of extracellular ligands to GPCRs activates a heterotrimeric G protein and triggers the production of numerous secondary messengers, which transduce the extracellular signals into cellular responses. GPCR signaling is crucial and imperative for maintaining normal tissue homeostasis. High-throughput sequencing analyses revealed the occurrence of the genetic aberrations of GPCRs and G proteins in multiple malignancies. The altered GPCRs/G proteins serve as valuable biomarkers for early diagnosis, prognostic prediction, and pharmacological targets. Furthermore, the dysregulation of GPCR signaling contributes to tumor initiation and development. In this review, we have summarized the research progress of GPCRs and highlighted their mechanisms in gastric cancer (GC). The aberrant activation of GPCRs promotes GC cell proliferation and metastasis, remodels the tumor microenvironment, and boosts immune escape. Through deep investigation, novel therapeutic strategies for targeting GPCR activation have been developed, and the final aim is to eliminate GPCR-driven gastric carcinogenesis.

Meningioma and Other Meningeal Tumors

Meningiomas develop from meningothelial cells and approximately account for more than 30 percent of central nervous system (CNS) tumors. They can occur anywhere in the dura, most often intracranially and at dural reflection sites. Half of the cases are usually at parasagittal/falcine and convexity locations; other common sites are sphenoid ridge, suprasellar, posterior fossa, and olfactory groove. The female-to-male ratio is approximately 2 or 3-1, and the median age at diagnosis is 65 years. Meningiomas are generally extremely slow-growing tumors; many are asymptomatic or paucisymptomatic at diagnosis and are discovered incidentally. Clinical manifestations, when present, are influenced by the tumor site and by the time course over which it develops. Meningiomas are divided into three grades. Grade I represents the vast majority of cases; they are considered typical or benign, although their CNS location can still lead to severe morbidity or mortality, resulting in a reported ten-year net survival of over 80%. Atypical (WHO grade II) meningiomas are considered "intermediate grade" malignancies and represent 5-7% of cases. They show a tendency for recurrence and malignant degeneration with a relevant increase in tumor cell migration and surrounding tissue infiltration; ten-year net survival is reported over 60%. The anaplastic subtype (WHO III) represents only 1-3% of cases, and it is characterized by a poor prognosis (ten-year net survival of 15%). The treatment of choice for these tumors stands on complete microsurgical resection in case the subsequent morbidities are assumed minimal. On the other hand, and in case the tumor is located in critical regions such as the skull base, or the patient may have accompanied comorbidities, or it is aimed to avoid intensive treatment, some other approaches, including stereotactic radiosurgery and radiotherapy, were recommended as safe and effective choices to be considered as a primary treatment option or complementary to surgery. Adjuvant radiosurgery/radiotherapy should be considered in the case of atypical and anaplastic histology, especially when a residual tumor is identifiable in postoperative imaging. A "watchful waiting" strategy appears reasonable for extremely old individuals and those with substantial comorbidities or low-performance status, while there is a reduced threshold for therapeutic intervention for relatively healthy younger individuals due to the expectation that tumor progression will inevitably necessitate proactive treatment. To treat and manage meningioma efficiently, the assessments of both neurosurgeons and radiation oncologists are essential. The possibility of other rarer tumors, including hemangiopericytomas, solitary fibrous tumors, lymphomas, metastases, melanocytic tumors, and fibrous histiocytoma, must be considered when a meningeal lesion is diagnosed, especially because the ideal diagnostic and therapeutic approaches might differ significantly in every tumor type.

Primitive pituitary perivascascular epithelioid cell tumor: A challenging diagnosis of melanocytic pituitary lesion

BACKGROUND

Perivascular Epithelioid cell tumors (PEComa) are rare mesenchymal tumors. They generally occur in the gynecologic or digestive tract. The diagnosis of Central Nervous System PEComa is exceptional and challenging.

CASE DESCRIPTION

We report the case of a 46-year-old woman, with no particular medical history, who presented a secondary amenorrhea and a slight hyperprolactinemia. She was diagnosed on MRI with a pituitary tumor showing spontaneous hypersignal in T1-weighted images. After failure of medical treatment with cabergoline, surgical resection was required due to progressive tumor growth. Macroscopic aspect and initial immunohistochemical features were in favor of a primitive hypophyseal melanocytoma. However, molecular and transcriptional study through targeted exome- and RNA-sequencing led to the exceptional diagnosis of pituitary Perivascular Epithelioid Cell Tumor (PEComa). Three-years of postoperative radio-clinical follow-up showed an asymptomatic non-evolutive small remnant.

CONCLUSION

PEComa is an exceptional diagnosis among pituitary tumors. It should be evoked as a potential differential diagnosis in case of primitive melanocytic lesion of the pituitary gland. Specific molecular analysis is mandatory to confirm the diagnosis and exclude differential diagnosis.

Intracranial meningeal melanocytomas: Clinico-radiological characteristics and outcomes. A Literature review

OBJECTIVES

Melanocytes are neural crest derivatives. Intracranial meningeal melanocytomas (MM) are rare tumors and the available literature is sparse for these neoplasms. This present review aims to provide a detailed and comprehensive literature review of these tumors.

MATERIALS AND METHODS

By searching online databases, literature review was performed to include and analyze all cases of cranial MM reported till date. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed for the review process.

RESULTS

A total of 109 cases were analyzed. Male:female ratio was 1.2:1. The mean age was 40.3 years. The mean duration of symptoms was 23.9 months (range 2days-15 years). Cerebellopontine (CP) angle, suprasellar and Meckel cave were the most common locations. Sixty-four cases (58%) underwent GTR. Twenty-eight patients (26%) received some form of adjuvant radiation. There were 29(26%) recurrences and mean time to recurrence was 50.2 months. The recurrence rates (RR) for GTR and STR were 20% and 42% respectively. Extent of resection (STR) and tumor locations (CP angle and Meckel cave) were significantly associated with higher RR. Six (6.5%) cases had higher-grade transformations.

CONCLUSIONS

Complete surgical resection is the ideal treatment and adjuvant radiation is to be considered for residual/recurrent tumors. Adjuvant radiotherapy may also be prescribed despite GTR, in locations with higher RR such as CP angle and Meckel's cave. Because of higher-grade transformations and delayed recurrences, long-term follow-up is required.

Primary intracranial malignant melanomas in solitary type: a tertiary center experience

PURPOSE

Solitary type primary intracranial malignant melanoma (PIMM) is extremely rare but fatal. The optimal treatment algorithm according to clinical relevance of symptoms and outcomes is unclear. This series emphasized the prognostic factors of solitary PIMM and established the treatment algorithm for this rare disease.

METHODS

Patients with solitary PIMMs were pathologically verified and treated with neurosurgical tumor resection. All solitary PIMMs recruited at our institute received multidisciplinary team care. We analyzed the clinical findings and prognostic factors.

RESULTS

The study cohort included 10 patients. PIMMs in solitary type impacted middle-aged populations with male predominance in Taiwan. Most patients (80%) presented a single tumor initially. Six patients had progressed to multiplicity after the initial treatment. Rates of tumor bleeding and leptomeningeal metastasis seeding (LS) are high in solitary PIMMs. Patients who had gross-total resection (GTR) had better survival than those who had incomplete resection, with median overall survival (OS) rates of 170.4 months vs. 5.23 months (p = 0.004). Multiplicity, eloquent area involvement, initial tumor bleeding, LS, hydrocephalus, and Karnofsky Performance Score < 80 at diagnosis were associated with negative outcomes in progression-free survival and OS. Adjuvant radiotherapy for patients who had LS and for those who cannot undergo grossly total tumor removal resulted in a good outcome.

CONCLUSIONS

GTR demonstrated better outcomes for solitary PIMM. For recurrent tumors, aggressively repeated surgical resection remained beneficial for selected cases. Adjuvant radiotherapy was a treatment option for LS following operation. We proposed a possible treatment algorithm for solitary PIMM.

Genetic alterations associated with malignant transformation of sporadic vestibular schwannoma

Introduction

Malignant peripheral nerve sheath tumor of the vestibulocochlear nerve (VN-MPNST) is exceedingly rare and carries a poor prognosis. Little is known about its underlying genetics and in particular the process of malignant transformation. There is an ongoing debate on whether the transformation is initiated by ionizing radiation. We present here the analysis and comparison of two post-radiation VN-MPNST and one undergoing spontaneous transformation.

Methods

Four tumors from three patients (radiation-naïve vestibular schwannoma before (VS) and after (VN-MPNST) malignant transformation in addition to two post-radiation VN-MPNST) were subjected to DNA whole-genome microarray and whole-exome sequencing and tumor-specific mutations were called. Mutational signatures were characterized using MuSiCa.

Results

The tumor genomes were characterized predominantly by copy-number aberrations with 36–81% of the genome affected. Even the VS genome was grossly aberrated. The spontaneous malignant transformation was characterized by a near-total whole-genome doubling, disappearance of NF2 mutation and new mutations in three cancer-related genes (GNAQ, FOXO4 and PDGFRB). All tumors had homozygous loss of the tumor suppressor CDKN2A. Neither mutational signature nor copy number profile was associated with ionizing radiation.

Conclusion

The VN-MPNST genome in our cases is characterized by large copy-number aberrations and homozygous deletion of CDKN2A. Our study demonstrates a VS with genetic alterations similar to its malignant counterpart, suggesting the existence of premalignant VS. No consistent mutational signature was associated with ionizing radiation.

Crosstalk with keratinocytes causes GNAQ oncogene specificity in melanoma

Different melanoma subtypes exhibit specific and non-overlapping sets of oncogene and tumor suppressor mutations, despite a common cell of origin in melanocytes. For example, activation of the Gα_q/11 signaling pathway is a characteristic initiating event in primary melanomas that arise in the dermis, uveal tract, or central nervous system. It is rare in melanomas arising in the epidermis. The mechanism for this specificity is unknown. Here, we present evidence that in the mouse, crosstalk with the epidermal microenvironment actively impairs the survival of melanocytes expressing the GNAQ^Q209L oncogene. We found that GNAQ^Q209L, in combination with signaling from the interfollicular epidermis (IFE), stimulates dendrite extension, leads to actin cytoskeleton disorganization, inhibits proliferation, and promotes apoptosis in melanocytes. The effect was reversible and paracrine. In contrast, the epidermal environment increased the survival of wildtype and Braf^V600E expressing melanocytes. Hence, our studies reveal the flip side of Gα_q/11 signaling, which was hitherto unsuspected. In the future, the identification of the epidermal signals that restrain the GNAQ^Q209L oncogene could suggest novel therapies for GNAQ and GNA11 mutant melanomas.

Primary meningeal melanoma masquerading as neurofibromatosis type 2: illustrative case

BACKGROUND

Primary meningeal melanocytic neoplasms are exceedingly rare tumors, representing only 0.06% to 0.1% of all primary brain tumors and ranging in spectrum from benign localized tumors to highly aggressive malignant lesions. The diagnosis of these tumors is often challenging from clinical, radiological, and pathologic standpoints. Equally challenging is the distinction between primary meningeal melanocytic neoplasm and metastatic melanoma.

OBSERVATIONS

The authors reported the case of a 41-year-old man with imaging findings diagnostic of neurofibromatosis type 2: bilateral internal auditory canal lesions (most consistent with bilateral vestibular schwannomas), two dura-based lesions presumed to be meningiomas, multiple spinal lesions consistent with peripheral nerve sheath tumors, and one intramedullary spinal lesion consistent with an ependymoma. Biopsy of these lesions revealed melanocytic neoplasms with mild to moderate atypia and a mildly elevated proliferation index, which made the distinction between benign and malignant challenging. In addition, the disseminated nature of these tumors made it difficult to determinate whether they arose from the meninges or represented metastases from an occult primary melanoma.

LESSONS

This case illustrated the challenges presented by the diagnosis of meningeal melanocytic neoplasms and highlighted the importance of integrating the clinical and radiographic findings with histologic appearance and molecular studies.

Uveal Melanoma Metastasis

Uveal melanoma (UM) is characterized by relatively few, highly incident molecular alterations and their association with metastatic risk is deeply understood. Nevertheless, this knowledge has so far not led to innovative therapies for the successful treatment of UM metastases or for adjuvant therapy, leaving survival after diagnosis of metastatic UM almost unaltered in decades. The driver mutations of UM, mainly in the G-protein genes GNAQ and GNA11, activate the MAP-kinase pathway as well as the YAP/TAZ pathway. At present, there are no drugs that target the latter and this likely explains the failure of mitogen activated kinase kinase inhibitors. Immune checkpoint blockers, despite the game changing effect in cutaneous melanoma (CM), show only limited effects in UM probably because of the low mutational burden of 0.5 per megabase and the unavailability of antibodies targeting the main immune checkpoint active in UM. The highly pro-tumorigenic microenvironment of UM also contributes to therapy resistance. However, T-cell redirection by a soluble T-cell receptor that is fused to an anti-CD3 single-chain variable fragment, local, liver specific therapy, new immune checkpoint blockers, and YAP/TAZ specific drugs give new hope to repeating the success of innovative therapy obtained for CM.

S-100-negative, GNA11 mutation-positive intramedullary meningeal melanocytoma of the thoracic spine: A radiographic challenge and histologic anomaly

Background:

Intramedullary melanocytomas are exceedingly rare and their management is largely based on case reports and small clinical series. They have characteristic imaging and histologic findings that can aid in their diagnosis. Genetic testing may be required for definitive diagnosis and management guidance in ambiguous cases.

Case Description:

We present the case of a thoracic intramedullary meningeal melanocytoma in a patient unable to undergo an MRI.

Conclusion:

This is the first reported S-100-negative case with genetic testing to support the diagnosis of a rare intramedullary melanocytoma.

SISTEMA: A large and standardized collection of transcriptome data sets for human pluripotent stem cell research

Human pluripotent stem cells have ushered in an exciting new era for disease modeling, drug discovery, and cell therapy development. Continued progress toward realizing the potential of human pluripotent stem cells will be facilitated by robust data sets and complementary resources that are easily accessed and interrogated by the stem cell community. In this context, we present SISTEMA, a quality-controlled curated gene expression database, built on a valuable catalog of human pluripotent stem cell lines, and their derivatives for which transcriptomic analyses have been generated using a single experimental pipeline. SISTEMA functions as a one-step resource that will assist the stem cell community to easily evaluate the expression level for genes of interest, while comparing them across different hPSC lines, cell types, pathological conditions, or after pharmacological treatments.

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SISTEMA is a curated gene expression database using human pluripotent stem cell lines

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A single experimental and analytical pipeline are used for the transcriptomic analyses

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SISTEMA is a user friendly Web portal designed for the stem cell community

A CHALLENGING CASE OF SPORADIC MELANOCYTOMA OF THE JUGULAR FORAMEN

BACKGROUND

The jugular foramen (JF) can be the site of several tumours. Paragangliomas, schwannomas and meningiomas are the most commonly reported. We describe a case of melanocytoma originating from the JF and presenting with an accessory nerve palsy. Illustrative case: A 48-year-old woman presented with a 6-month history of cervical and left shoulder pain with wasting and weakness of the left trapezius. A Magnetic Resonance Imaging (MRI) showed a T1-hyperintense, T2-isointense, heterogeneously enhancing lesion involving the left JF and extending into the cerebello-medullary and cerebello-pontine cisterns. A retrosigmoid craniotomy was performed and a near total removal achieved. The accessory nerve was involved by tumour and could not be preserved. Given the diagnostic uncertainty between melanotic schwannoma, metastatic melanoma and meningeal melanocytoma, next generation sequencing and genome-wide DNA methylation arrays were performed, documenting a mutation in GNA11 (c.6226A>T, p. Gln209Leu) and a methylation profile consistent with melanocytoma. The patient underwent adjuvant fractionated radiotherapy of the tumour remnant. A follow-up MRI 4 years after surgery did not show any tumour recurrence.

CONCLUSIONS

The differential diagnosis of skull base pigmented tumours can be challenging, particularly when they occur in unusual locations such as the JF. They can be misdiagnosed given their similar clinical, neuroradiological and pathological features if anatomy of the site of origin is not carefully considered and molecular tests are not performed, leading to erroneous treatment and follow up planning.

Combined Inhibition of Gαq and MEK Enhances Therapeutic Efficacy in Uveal Melanoma

PURPOSE

All uveal melanoma and a fraction of other melanoma subtypes are driven by activation of the G-protein alpha-q (Gαq) pathway. Targeting these melanomas has proven difficult despite advances in the molecular understanding of key driver signaling pathways in the disease pathogenesis. Inhibitors of Gαq have shown promising preclinical results, but their therapeutic activity in distinct Gαq mutational contexts and in vivo have remained elusive.

EXPERIMENTAL DESIGN

We used an isogenic melanocytic cellular system to systematically examine hotspot mutations in GNAQ (e.g., G48V, R183Q, Q209L) and CYSLTR2 (L129Q) found in human uveal melanoma. This cellular system and human uveal melanoma cell lines were used in vitro and in in vivo xenograft studies to assess the efficacy of Gαq inhibition as a single agent and in combination with MEK inhibition.

RESULTS

We demonstrate that the Gαq inhibitor YM-254890 inhibited downstream signaling and in vitro growth in all mutants. In vivo, YM-254890 slowed tumor growth but did not cause regression in human uveal melanoma xenografts. Through comprehensive transcriptome analysis, we observed that YM-254890 caused inhibition of the MAPK signaling with evidence of rebound by 24 hours and combination treatment of YM-254890 and a MEK inhibitor led to sustained MAPK inhibition. We further demonstrated that the combination caused synergistic growth inhibition in vitro and tumor shrinkage in vivo.

CONCLUSIONS

These data suggest that the combination of Gαq and MEK inhibition provides a promising therapeutic strategy and improved therapeutic window of broadly targeting Gαq in uveal melanoma.See related commentary by Neelature Sriramareddy and Smalley, p. 1217.

Identification of a Novel BRCA1 Alteration in Recurrent Melanocytoma Resulting in Increased Proliferation

Primary meningeal melanocytomas are rare tumors of the central nervous system. Although they are considered benign neoplasms, some reports describe recurrent rates up to 45%. Little is known about their genetic and epigenetic landscape because of their infrequency. Even less has been described about markers with prognostic value. Here we describe a patient who developed a primary meningeal melanocytoma, suffered 3 recurrences in a period of 6 years and died of the tumor. The genetic and epigenetic changes explored confirmed GNAQ mutation as an initiating event. We found an epigenetic alteration of GSTP1, a feature that has recently been described in meningiomas, from the beginning of the disease. In addition, there was loss of heterozygosity in BRCA1 beginning in the second recurrence that was linked to an increase in the proliferation index; this suggested a progression pathway similar to the one described in uveal melanomas. These findings underscore the necessity of further research focused on these tumors.

EANO guideline on the diagnosis and treatment of vestibular schwannoma

The level of evidence to provide treatment recommendations for vestibular schwannoma is low compared with other intracranial neoplasms. Therefore, the vestibular schwannoma task force of the European Association of Neuro-Oncology assessed the data available in the literature and composed a set of recommendations for health care professionals. The radiological diagnosis of vestibular schwannoma is made by magnetic resonance imaging. Histological verification of the diagnosis is not always required. Current treatment options include observation, surgical resection, fractionated radiotherapy, and radiosurgery. The choice of treatment depends on clinical presentation, tumor size, and expertise of the treating center. In small tumors, observation has to be weighed against radiosurgery, in large tumors surgical decompression is mandatory, potentially followed by fractionated radiotherapy or radiosurgery. Except for bevacizumab in neurofibromatosis type 2, there is no role for pharmacotherapy.

Targeting primary and metastatic uveal melanoma with a G protein inhibitor

Uveal melanoma (UM) is the most common intraocular tumor in adults. Nearly half of UM patients develop metastatic disease and often succumb within months because effective therapy is lacking. A novel therapeutic approach has been suggested by the discovery that UM cell lines driven by mutant constitutively active Gq or G11 can be targeted by FR900359 (FR) or YM-254890, which are bioavailable, selective inhibitors of the Gq/11/14 subfamily of heterotrimeric G proteins. Here, we have addressed the therapeutic potential of FR for UM. We found that FR inhibited all oncogenic Gq/11 mutants reported in UM. FR arrested growth of all Gq/11-driven UM cell lines tested, but induced apoptosis only in a few. Similarly, FR inhibited growth of, but did not efficiently kill, UM tumor cells from biopsies of primary or metastatic tumors. FR evoked melanocytic redifferentiation of UM tumor cells with low (class 1), but not high (class 2), metastatic potential. FR administered systemically below its LD₅₀ strongly inhibited growth of PDX-derived class 1 and class 2 UM tumors in mouse xenograft models and reduced blood pressure transiently. FR did not regress xenografted UM tumors or significantly affect heart rate, liver function, hematopoiesis, or behavior. These results indicated the existence of a therapeutic window in which FR can be explored for treating UM and potentially other diseases caused by constitutively active Gq/11.

Primary intra-abdominal melanoma arising in association with extracutaneous blue naevus: a report of two cases

AIMS

Blue naevi are uncommon dermal melanocytic neoplasms characterised by GNAQ/GNA11 mutations, which very rarely progress to melanoma. Such melanomas also often have BAP1 mutations, and lack genetic events associated with conventional melanoma. Exceptionally, blue naevi arise in extracutaneous locations; one melanoma arising in this setting has been reported. We report the clinicopathological, immunohistochemical and molecular genetic features of two cases of melanoma arising in extracutaneous blue naevus.

METHODS AND RESULTS

Both arose in males, aged 25 and 63 years, with no history of other melanocytic lesions, and presented as large, painful intra-abdominal masses. The tumours were dark-brown/black, multilobulated, involved small intestinal mesentery and consisted of a predominantly fascicular and spindled, but occasionally nested and epithelioid, proliferation of variably pigmented, relatively monotonous cells with pale cytoplasm and ovoid nuclei with mild to moderate atypia. Mitotic activity was variable but generally low. Both cases showed areas of conventional and cellular blue naevus. Recurrent tumour in one case showed predominantly epithelioid morphology and greater cytological atypia and mitotic activity. One case expressed Melan-A, SOX10 and CD117, with absent expression of S100 protein and DOG1; the other expressed Melan-A, HMB45 and S100 protein. Next-generation sequencing identified GNAQ and BAP1 mutations in one case and GNA11 mutation in the other. Both patients developed widespread metastatic disease.

CONCLUSION

Exceptionally rare, aggressive melanomas arising in extracutaneous blue naevi should be distinguished from metastatic melanoma, gastrointestinal stromal tumour and malignant melanotic nerve sheath tumour, especially given the significant therapeutic and prognostic differences between these different entities.

Pituitary metastasis of malignant melanoma misdiagnosed as pituitary adenoma: A case report and systematic review of the literature

We report a case of malignant melanoma revealed by a metastasis to the pituitary gland. The tumor was misdiagnosed as a pituitary adenoma and aggressive transsphenoidal surgery was complicated by a cerebrospinal fluid fistula. Nine weeks later, the patient presented multiple leptomeningeal and brain metastases spreading from the sellar region. Regarding these observations, we conducted a systematic review of the literature in order to investigate clinicoradiological features that should lead clinicians to suspect pituitary metastasis and how it should impact the surgical management.

Endothelin signaling promotes melanoma tumorigenesis driven by constitutively active GNAQ

The G-protein-coupled receptor, endothelin receptor B (EDNRB), is an important regulator of melanocyte survival and proliferation. It acts by stimulating downstream heterotrimeric G proteins, such as Gα_q and Gα₁ . Constitutively active, oncogenic versions of Gα_q and Gα₁₁ drive melanomagenesis, but the role of Ednrb in the context of these mutant G proteins has not been previously examined. In this paper, we used a knock-in mouse allele at the Rosa26 locus to force oncogenic GNAQ^Q209L expression in melanocytes in combination with Ednrb gene knockout. The resulting pathological analysis revealed that every aspect of melanomagenesis driven by GNAQ^Q209L was inhibited. We conclude that even in the presence of oncogenic Gα_q , the Ednrb receptor activates normal Gα_q and Gα₁₁ proteins. This likely promotes tumorigenesis by activating phospholipase C-beta, the immediate effector of Gα_q/11 . These findings suggest that it might be possible to target upstream receptors to offset the effects of hyperactive G proteins, recognized as the cause of a growing number of human disorders.

Primary sellar melanocytoma: pathological, clinical and treatment review

BACKGROUND

Sellar melanocytomas represent a small subgroup of primary melanocytic tumors. They arise from melanocytes located in the meningeal lining of the sellar floor or in the diaphragma sellae and this location is very uncommon. Usually, sellar melanocytomas are benign and slow-growing tumors with a high likelihood of recurrence.

PURPOSE

To our knowledge, due to the rarity of this condition, there are no guidelines regarding their diagnosis and treatment in the medical literature to date. We have developed a narrative review, analyzing the available studies regarding primary sellar melanocytomas reported in the medical literature. We have found ten papers on this topic and all of them are case reports. In all patients, tumor diagnosis was performed after the occurrence of neurological symptoms, in particular progressive visual loss or endocrinological disorders. The diagnosis is difficult, and it requires several preoperative and postoperative investigations, but histological examination is crucial.

CONCLUSIONS

Transsphenoidal surgery is the first-choice treatment. In case of tumor's recurrence or regrowth, the role of radiation therapy and chemotherapy is not entirely clear.

Cytologic Evaluation of Tumor-Infiltrating Lymphocytes for Adoptive Cell Therapy

OBJECTIVES

Novel immunotherapeutic options for refractory metastatic cancer patients include adoptive cell therapies such as tumor infiltrating lymphocytes (TILs). This study characterizes the clinicopathologic findings in a cohort of TIL specimens.

METHODS

Patients with metastatic malignancy who were eligible had TILs from their metastases grown and expanded and then sent to pathology.

RESULTS

A total of 11 TIL specimens (10 melanoma, 1 adenocarcinoma) from patients enrolled in an experimental clinical trial were reviewed. All specimens showed more than 200 lymphoid cells, stained positive for lymphoid markers confirming an activated cytotoxic T-cell immunophenotype, and morphologically showed an intermediate-sized population with immature chromatin and frequent mitoses. Six cases (55%) showed large cells with nucleomegaly and prominent nucleoli.

CONCLUSIONS

This report is the first describing cytopathologic findings of autologous TIL therapy including adequacy guidelines and expected cytomorphologic and immunophenotypic findings. To meet this novel clinical demand, a predefined cytology protocol to rapidly process and interpret these specimens needs to be established.

Molecular pathology of tumors of the central nervous system

Since the update of the 4th edition of the WHO Classification of Central Nervous System (CNS) Tumors published in 2016, particular molecular characteristics are part of the definition of a subset of these neoplasms. This combined 'histo-molecular' approach allows for a much more precise diagnosis of especially diffuse gliomas and embryonal CNS tumors. This review provides an update of the most important diagnostic and prognostic markers for state-of-the-art diagnosis of primary CNS tumors. Defining molecular markers for diffuse gliomas are IDH1/IDH2 mutations, 1p/19q codeletion and mutations in histone H3 genes. Medulloblastomas, the most frequent embryonal CNS tumors, are divided into four molecularly defined groups according to the WHO 2016 Classification: wingless/integrated (WNT) signaling pathway activated, sonic hedgehog (SHH) signaling pathway activated and tumor protein p53 gene (TP53)-mutant, SHH-activated and TP53-wildtype, and non-WNT/non-SHH-activated. Molecular characteristics are also important for the diagnosis of several other CNS tumors, such as RELA fusion-positive subtype of ependymoma, atypical teratoid rhabdoid tumor (AT/RT), embryonal tumor with multilayered rosettes, and solitary fibrous tumor/hemangiopericytoma. Immunohistochemistry is a helpful alternative for further molecular characterization of several of these tumors. Additionally, genome-wide methylation profiling is a very promising new tool in CNS tumor diagnostics. Much progress has thus been made by translating the most relevant molecular knowledge into a more precise clinical diagnosis of CNS tumors. Hopefully, this will enable more specific and more effective therapeutic approaches for the patients suffering from these tumors.

Genomic evolution of uveal melanoma arising in ocular melanocytosis

Ocular melanocytosis is the most important predisposing condition for the eye cancer uveal melanoma (UM). Here, we present a patient who developed UM arising within ocular melanocytosis who was treated with enucleation (eye removal), which provided an invaluable opportunity to interrogate both the UM and adjacent uveal tissue containing the melanocytosis using whole-exome and deep-targeted sequencing. This analysis revealed a clonal PLCB4 mutation in the melanocytosis, confirming that this is indeed a neoplastic condition and explaining why it predisposes to UM. This mutation was present in 100% of analyzed UM cells, indicating that a PLCB4-mutant cell gave rise to the UM. The earliest aberrations specific to the tumor were loss of Chromosomes 1p, 3, and 9p, which were present in virtually all tumor cells. A mutation in BAP1 arose later on the other copy of Chromosome 3 in a tumor subclone, followed by a gain of Chromosome 8q. These findings provide a mechanistic explanation for the well-known clinical association between ocular melanocytosis and UM by showing that this predisposing condition introduces the first “hit” and thereby increases the stochastic likelihood of acquiring further aberrations leading to UM.

A cellular blue nevus with pigmented epithelioid melanocytoma-like pattern on the ipsilateral upper arm associated with a congenital plaque-type blue nevus on the hand

A 36-year-old man presented with a subcutaneous nodule on the right upper arm. A small nodule had developed 8 years earlier, and grew in size, accompanied by a tingling sensation and numbness. In addition, he had a bluish irregular patch on the right hand since birth, which crossed from the palm to the dorsal hand. Skin biopsies from the hand showed a heavily pigmented melanocyte proliferation in the dermis with perieccrine, perivascular, and perineural involvement, and a diagnosis of congenital plaque-type blue nevus was made. The tumor on the arm was located closely along the median nerve, and was observed as a large black pedunculated round tumor. Histopathologically, the tumor on the arm consisted of densely packed tissue with nevoid cells without atypia in the larger nodular part, and heavily pigmented spindle and epithelioid melanocytes in the slender stalk area, which was diagnosed as cellular blue nevus with pigmented epithelioid melanocytoma-like pattern. Next-generation sequencing revealed GNAQ mutations in the hand lesion, and in the lesions on the arm. This case suggests that the areas of skin following the same neural distribution of a congenital plaque-type blue nevus on the extremities should be followed up for secondary changes.

Defining the Molecular Genetics of Dermoscopic Naevus Patterns

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

Integrated Genomic Classification of Melanocytic Tumors of the Central Nervous System Using Mutation Analysis, Copy Number Alterations, and DNA Methylation Profiling

Purpose: In the central nervous system, distinguishing primary leptomeningeal melanocytic tumors from melanoma metastases and predicting their biological behavior solely using histopathologic criteria may be challenging. We aimed to assess the diagnostic and prognostic value of integrated molecular analysis.Experimental Design: Targeted next-generation sequencing, array-based genome-wide methylation analysis, and BAP1 IHC were performed on the largest cohort of central nervous system melanocytic tumors analyzed to date, including 47 primary tumors of the central nervous system, 16 uveal melanomas, 13 cutaneous melanoma metastases, and 2 blue nevus-like melanomas. Gene mutation, DNA-methylation, and copy-number profiles were correlated with clinicopathologic features.Results: Combining mutation, copy-number, and DNA-methylation profiles clearly distinguished cutaneous melanoma metastases from other melanocytic tumors. Primary leptomeningeal melanocytic tumors, uveal melanomas, and blue nevus-like melanoma showed common DNA-methylation, copy-number alteration, and gene mutation signatures. Notably, tumors demonstrating chromosome 3 monosomy and BAP1 alterations formed a homogeneous subset within this group.Conclusions: Integrated molecular profiling aids in distinguishing primary from metastatic melanocytic tumors of the central nervous system. Primary leptomeningeal melanocytic tumors, uveal melanoma, and blue nevus-like melanoma share molecular similarity with chromosome 3 and BAP1 alterations, markers of poor prognosis. Clin Cancer Res; 24(18); 4494-504. ©2018 AACR.

BRAF, NRAS, and GNAQ Mutations in Conjunctival Melanocytic Nevi

Purpose

To evaluate BRAF, NRAS, and GNAQ mutations in surgical specimens of common and blue conjunctival melanocytic nevi.

Methods

Surgical specimens from 25 conjunctival melanocytic nevi (23 common and 2 blue) of 25 patients were evaluated. All common nevi were analyzed immunohistochemically for the expression of BRAF V600E or NRAS Q61R. One lesion with negative immunoreactivity and for all blue nevi, a hybridization capture-based next-generation sequencing method was employed for mutation analysis. For common nevi, genetic features were compared with clinical and histopathologic findings. Continuous variables (age at excision and largest basal diameter) were compared with a Students's t-test and all categoric variables were compared with Fisher's Exact Test.

Results

Of common melanocytic nevi, 9 (39.1%) were immunoreactive for NRASQ61R and 13 (56.5%) were immunoreactive for BRAFV600E. One common nevus, which was immunonegative for both BRAFV600E and NRASQ61R was found to harbor an NRASQ61K mutation by sequence analysis. Patients with NRAS-mutated nevi were more likely to report occurrence of the lesion prior to 18-years old and more likely to have intrinsic cysts. The mean largest basal diameter was 6.0 and 3.5 mm for NRAS- and BRAF-immunoreactive lesions, respectively (P = 0.003). GNAQ mutations were identified in each of the two blue nevi of this study.

Conclusions

These findings document that common conjunctival melanocytic nevi have mutually exclusive mutations in BRAF and NRAS. The two conjunctival blue nevi harbored GNAQ mutations. This suggests the driver mutations of conjunctival nevi are similar to those of nevi of the skin. At the molecular level, conjunctival nevi appear more like cutaneous nevi than choroidal nevi.

Intraventricular melanocytoma diagnosis confirmed by gene mutation profile

Primary leptomeningeal melanocytic tumors (PLMTs) are rare. They usually arise along the spinal cord and at the skull base. Here we report on a patient with a very rare intraventricular melanocytoma. Histologically, a melanocytic tumor was clearly diagnosed. However, to make the uncommon diagnosis of an intraventricular melanocytoma, metastatic melanoma needed to be excluded. Next generation sequencing covering gene mutations that may occur in PLMTs and cutaneous melanoma was performed. The unique gene mutation profile detected, consisting of an activating CYSLTR2 L129Q mutation and EIF1AX G9R mutation and a lack of mutations in genes known to occur in metastatic melanoma (i.e. BRAF or NRAS) confirmed the diagnosis of an intraventricular melanocytoma. This case report is the second intraventricular melanocytoma published to date and demonstrates the value of applying novel genetic assays to make this diagnosis.

The biology of uveal melanoma

Uveal melanoma (UM), a rare cancer of the eye, is distinct from cutaneous melanoma by its etiology, the mutation frequency and profile, and its clinical behavior including resistance to targeted therapy and immune checkpoint blockers. Primary disease is efficiently controlled by surgery or radiation therapy, but about half of UMs develop distant metastasis mostly to the liver. Survival of patients with metastasis is below 1 year and has not improved in decades. Recent years have brought a deep understanding of UM biology characterized by initiating mutations in the G proteins GNAQ and GNA11. Cytogenetic alterations, in particular monosomy of chromosome 3 and amplification of the long arm of chromosome 8, and mutation of the BRCA1-associated protein 1, BAP1, a tumor suppressor gene, or the splicing factor SF3B1 determine UM metastasis. Cytogenetic and molecular profiling allow for a very precise prognostication that is still not matched by efficacious adjuvant therapies. G protein signaling has been shown to activate the YAP/TAZ pathway independent of HIPPO, and conventional signaling via the mitogen-activated kinase pathway probably also contributes to UM development and progression. Several lines of evidence indicate that inflammation and macrophages play a pro-tumor role in UM and in its hepatic metastases. UM cells benefit from the immune privilege in the eye and may adopt several mechanisms involved in this privilege for tumor escape that act even after leaving the niche. Here, we review the current knowledge of the biology of UM and discuss recent approaches to UM treatment.

Targeted massively parallel sequencing of angiosarcomas reveals frequent activation of the mitogen activated protein kinase pathway

Angiosarcomas are rare malignant mesenchymal tumors of endothelial differentiation. The clinical behavior is usually aggressive and the prognosis for patients with advanced disease is poor with no effective therapies. The genetic bases of these tumors have been partially revealed in recent studies reporting genetic alterations such as amplifications of MYC (primarily in radiation-associated angiosarcomas), inactivating mutations in PTPRB and R707Q hotspot mutations of PLCG1. Here, we performed a comprehensive genomic analysis of 34 angiosarcomas using a clinically-approved, hybridization-based targeted next-generation sequencing assay for 341 well-established oncogenes and tumor suppressor genes. Over half of the angiosarcomas (n = 18, 53%) harbored genetic alterations affecting the MAPK pathway, involving mutations in KRAS, HRAS, NRAS, BRAF, MAPK1 and NF1, or amplifications in MAPK1/CRKL, CRAF or BRAF. The most frequently detected genetic aberrations were mutations in TP53 in 12 tumors(35%) and losses of CDKN2A in9 tumors (26%). MYC amplifications were generally mutually exclusive of TP53 alterations and CDKN2A loss and were identified in 8 tumors (24%), most of which (n = 7, 88%) arose post-irradiation. Previously reported mutations in PTPRB (n = 10, 29%) and one (3%) PLCG1 R707Q mutation were also identified. Our results demonstrate that angiosarcomas are a genetically heterogeneous group of tumors, harboring a wide range of genetic alterations. The high frequency of genetic events affecting the MAPK pathway suggests that targeted therapies inhibiting MAPK signaling may be promising therapeutic avenues in patients with advanced angiosarcomas.

Subcutaneous melanocytoma mimicking a lipoma: a rare presentation of a rare neoplasm with histological, immunohistochemical, cytogenetic and molecular characterization

Melanocytoma are the melanocytic tumors originating from leptomeningeal melanocytes. Melanocytomas are commonly seen in the central nervous system (CNS) and are often associated with neurocutaneous melanosis (NCM). However, simultaneous presentation of intra-axial and extracranial melanocytoma is a very rare event. Here, we report a unique case of 21-year-old male with intermediate-grade subcutaneous (SC) melanocytoma, mimicking lipoma, occurred synchronously with an intracranial melanocytoma, not associated with NCM. A 21-year-old Caucasian male presented to the emergency department (ED) with severe vertigo and vomiting. A magnetic resonance imaging (MRI) of the brain was performed at the ED, which revealed an SC mass in the right occipital scalp and a right cerebellopontine angle (CPA) mass. Excision of the SC mass revealed a well-circumscribed highly pigmented melanocytic tumor. The SC mass tumor cells were positive for melanocytic lineage markers. The histopathological features were between benign melanocytomas and malignant melanomas. The Ki67 and PHH3 IHCs confirm the intermediate grade of the tumors. An array-CGH (comparative genome hybridization) and next-generation sequencing analysis of the tumor DNA extracted from the formalin-fixed paraffin-embedded tissue reveals chromosome 6p gain and p.Q209P mutation in the GNAQ gene, respectively, consistent with the diagnosis of intermediate-grade melanocytoma.

Orbital meningeal melanocytoma: Histological, immunohistochemical and molecular characterization of a case and review of the literature

AIMS

We provide morphological, immunohistochemical and molecular characterization of the 3rd "intermediate-grade" orbital meningeal melanocytoma, testing for the first time Vysis Melanoma FISH Probe Kit. We reviewed the literature in order to discuss the main differential diagnoses and to provide a better molecular description of these unusual tumors of difficult diagnosis and controversial management.

METHODS

Histochemical stains (Haematoxylin and Eosin, Perls, reticulin), immunohistochemistry (HMB45, p16, Melan-A, S100, EMA, Ki67, CD68), polymerase chain reaction amplification and sequence analysis (BRAF, exon 15; NRAS exons 2 and 3; c-KIT, exons 11, 13, 17, 18; GNAQ, exons 4 and 5; GNA11, exons 4 and 5) and fluorescent in situ hybridization (RREB1, 6p25; MYB, 6q23; CCND1, 11q13; CEP 6, 6p11.1-q11.1) were performed on paraffin-embedded, formalin-fixed material.

RESULTS

Histological diagnosis of "intermediate-grade" melanocytoma was supported by zonal necrosis and increased Ki67-index (12%). Immunophenotype: HMB45+(strong, >75%), Melan-A+(strong, >75%), p16+(∼20%), S100 -/+ (<5%), EMA -/+ (<5%), CD68 - (positive histiocytes). No gene mutations nor copy-number alterations were identified. The patient was asymptomatic and disease-free 3 years after total surgical excision.

CONCLUSIONS

Adequate sampling and accurate immunohistochemical characterization are important for a correct diagnosis. Molecular analysis could provide important additional information (especially for "intermediate-grade" tumors), but further data are needed.

Gnaq and Gna11 in the Endothelin Signaling Pathway and Melanoma

In this article, we first briefly outline the function of G protein coupled receptors in cancer, and then specifically examine the roles of the seven transmembrane G protein coupled Endothelin B receptor (Ednrb) and the G proteins, GNAQ and GNA11, in both melanocyte development and melanoma. Ednrb plays an essential role in melanocyte development. GNAQ and GNA11 are oncogenes when mutated in certain types of melanocytic lesions, being extremely frequent in uveal melanoma, which forms from melanocytes located in the eye. Previously, we reported that in mice, Schwann cell precursor derived melanocytes colonize the dermis and hair follicles, while the inter-follicular epidermis is populated by other melanocytes. A pattern has emerged whereby melanocytes whose activities are affected by gain-of-function mutations of the Endothelin 3 ligand and Gα_q/11 are the same subset that arise from Schwann cell precursors. Furthermore, the forced expression of the constitutively active human GNAQ^Q209L oncogene in mouse melanocytes only causes hyper-proliferation in the subset that arise from Schwann cell precursors. This has led us to hypothesize that in Schwann cell precursor derived melanocytes, Ednrb signals through Gα_q/11. Ednrb is promiscuous and may signal through other G protein alpha subunits in melanomas located in the inter-follicular epidermis.

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

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