Sturge-Weber Syndrome: A Review of Pathophysiology, Genetics, Clinical Features, and Current Management Approache.

Sturge-Weber syndrome (SWS) is a congenital, sporadic, and rare neurocutaneous disorder, characterized by the presence of a facial port-wine birthmark (PWB), glaucoma, and neurological manifestations including leptomeningeal angiomatosis and seizures. It is caused by a postzygotic, somatic, gain-of-function variant of the GNAQ gene, and more recently, the GNA11 gene in association with distinctive clinical features. Neuroimaging can help identify and stratify patients at risk for significant complications allowing closer follow-up; although no presymptomatic treatment has been demonstrated to be effective to date, these patients could benefit from early treatment and/or supportive interventions. Choroid plexus (CP) thickness measurements in brain magnetic resonance imaging (MRI) have a high sensitivity and specificity for early and incipient changes in SWS. In contrast, the absence of pathologic findings makes it possible to rule out associated neurological involvement and leads to periodical observation, with new imaging studies only in cases of new clinical signs/symptoms. Periodic ophthalmological examination is also recommended every 3 months during the first year and yearly afterwards to monitor for glaucoma and choroidal hemangiomas. Treatment for SWS depends on the extent and areas that are affected. These include laser surgery for PWB, anticonvulsants in the case of brain involvement, with either seizures or abnormal EEG, and medical treatment or surgery for glaucoma. Sirolimus has been used in a limited number of patients and appears to be a safe and potentially effective treatment for cutaneous and extra-cutaneous features, however controlled clinical studies have not been carried out. Better knowledge of GNAQ/GNA11 molecular pathways will help to develop future targeted treatments.

Whole-genome CRISPR screening identifies PI3K/AKT as a downstream component of the oncogenic GNAQ-focal adhesion kinase signaling circuitry.

G proteins and G protein-coupled receptors activate a diverse array of signal transduction pathways that promote cell growth and survival. Indeed, hot spot-activating mutations in GNAQ/GNA11, encoding Gαq proteins, are known to be driver oncogenes in uveal melanoma (UM), for which there are limited effective therapies currently available. Focal adhesion kinase (FAK) has been recently shown to be a central mediator of Gαq-driven signaling in UM, and as a result, is being explored clinically as a therapeutic target for UM, both alone and in combination therapies. Despite this, the repertoire of Gαq/FAK-regulated signaling mechanisms have not been fully elucidated. Here, we used a whole-genome CRISPR screen in GNAQ-mutant UM cells to identify mechanisms that, when overactivated, lead to reduced sensitivity to FAK inhibition. In this way, we found that the PI3K/AKT signaling pathway represented a major resistance driver. Our dissection of the underlying mechanisms revealed that Gαq promotes PI3K/AKT activation via a conserved signaling circuitry mediated by FAK. Further analysis demonstrated that FAK activates PI3K through the association and tyrosine phosphorylation of the p85 regulatory subunit of PI3K and that UM cells require PI3K/AKT signaling for survival. These findings establish a novel link between Gαq-driven signaling and the stimulation of PI3K as well as demonstrate aberrant activation of signaling networks underlying the growth and survival of UM and other Gαq-driven malignancies.

Early detection of metastatic uveal melanoma by the analysis of tumor-specific mutations in cell-free plasma DNA.

BACKGROUND: Eye salvaging therapy of malignant melanomas of the uvea can preserve the eye in most cases, but still about half of patients die from metastatic disease. Previous analyses of cell-free DNA from plasma had shown detectable levels of tumor-specific GNAQ/GNA11 mutations in patients with the clinical diagnosis of progressive disease. However, data on the time span that elapses from the detection of ctDNA in plasma to the clinical detection of metastases (diagnostic lead time) are missing. METHODS: We examined 135 patients with uveal melanoma. Cell-free DNA was isolated from a total of 807 blood samples which were taken over a period of up to 41 months and analyzed for the presence of GNAQ/GNA11 mutations by deep amplicon sequencing. RESULTS: Twenty-one of the 135 patients developed metastases or recurrence. A ctDNA signal was identified in the plasma of 17 of the 21 patients. In 10 patients, this ctDNA signal preceded the clinical diagnosis of metastasis by 2-10 months. In 10 other patients, a ctDNA signal was only detected in samples obtained shortly before or after radiotherapy. The presence of a ctDNA signal in 16 of the remaining 125 patients was linked to clinical manifestation of metastases (n = 14) or tumor recurrence (n = 2) with a sensitivity and specificity of 80% and 96%, respectively. CONCLUSION: Detection of ctDNA in plasma can provide a diagnostic lead time over the clinical diagnosis of metastases or tumor recurrence. Longer lead times are to be expected if intervals between sampling are shortened.

Uveal melanoma: progress in molecular biology and therapeutics.

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

Genomic analysis reveals low tumor mutation burden which may be associated with GNAQ/11 alteration in a series of primary leptomeningeal melanomas.

Primary central nervous system melanoma is rare and characterized by a variable prognosis, and no current treatment guidelines exist. We describe the clinical course of a 70-year-old female patient diagnosed with primary leptomeningeal melanoma (LMN) whose case represents the diagnostic and management challenges of this tumor. Targeted genomic sequencing of 315 genes from this tumor revealed GNAQ Q209L mutation and low (4 mutations/Megabase) tumor mutation burden (TMB). Wild-type NRAS, KIT, and BRAF were also observed. A cohort of 4,787 melanomas was subsequently analyzed to identify additional primary central nervous system melanomas, of which 10 additional tumors met pathologic criteria (0.21% of total melanoma cohort). These tumors were genomically assessed according to the same targeted sequencing panel, and 6 of the tumors were also found to harbor a GNAQ mutation. All 10 tumors had low (less than or equal to 2 mutations/Megabase) TMB indicating a potential trend between G-protein-coupled receptor (GPCR) alterations and low TMB in LMNs. GPCR alterations were found to significantly correlate with TMB across the cohort of 4,787 melanomas, supporting this potential finding in the limited LMN subset.

Study of Gq mutations and their inhibitors in uveal melanoma / 药学学报

Uveal melanoma (UM) is one of most common ocular cancers and is extremely malignant; so far there is no effective treatment. Moreover, the survival period is only 2-7 months after metastasis. It has been proven that more than 83% of uveal melanomas harbor mutations in G protein subunit α q (GNAQ) or G protein subunit α 11 (GNA11), among which 95% are a Q209P/L single-site mutation. Q209P/L mutations lead to dysfunction of guanine triphosphatase (GTPase) in the G protein and result in constitutive activation of downstream pathways including mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT), Ras homologue (Rho)/ Rho-associated kinase (Rock)/Yes-associated protein (YAP) and others. Therefore, targeting GNAQ/GNA11 mutations are potential strategies for UM treatment. This review will focus on roles of G protein mutations in UM progression, and the potential therapeutic effects of GNAQ/GNA11 inhibitors, and will provide insights into basic and clinical research on UM treatment.

GNAQ and PMS1 Mutations Associated with Uveal Melanoma, Ocular Surface Melanosis, and Nevus of Ota.

G protein mutations are common in uveal melanomas, and the vast majority target amino acid residue Q209 in either GNAQ or GNA11. The GNAQ R183Q mutation is found in a small fraction of uveal melanomas. We report a patient with an unusual presentation of uveal melanoma arising at an early age in the setting of congenital skin and ocular surface melanosis. A 34-year-old Hispanic female with congenital bilateral nevus of Ota and ocular surface melanosis presented with progressive loss of visual acuity and was found to have a juxtapapillary uveal melanoma. She was treated with brachytherapy, but the tumor relapsed. She underwent enucleation that revealed mixed spindle and epithelioid uveal melanoma cells with no extraocular or lymphovascular spread. Next-generation sequencing performed on DNA isolated from the enucleation specimen identified a GNAQ R183Q mutation and a PMS1 truncation mutation. Cytogenetic profiling revealed no monosomy 3. These findings raise the possibility that uveal melanomas bearing G protein R183 mutations may have distinct clinicopathologic profiles compared to those with Q209 mutations. Furthermore, this is the first reported case of a mutation in the mismatch repair gene PMS1 associated with uveal melanoma.

Frequent and Yet Unreported GNAQ and GNA11 Mutations are Found in Uveal Melanomas.

Malignant melanoma of the uvea is the most common primary malignant tumor in the eye. We aimed to analyze GNAQ and GNA11 mutations in uveal melanomas using formalin-fixed, paraffin-embedded material and correlate the results with clinicopathological parameters. Tumor tissue was microdissected followed by amplification of GNAQ exon 4 and 5, GNA11 exon 4 and 5, and finally analyzed by Sanger sequencing. A total of 64.4 GNA11/GNAQ mutations, including ten yet unreported, were found. Two cases showed multiple mutations. Overall survival was significantly shorter in the uveal melanoma cohort with GNAQ exon 5 mutation. In concordance with previous studies, high frequencies of mutations in GNAQ or GNA11 were detected. Interestingly, in about 20% of UM, not yet reported mutations in GNAQ or GNA11 were seen. Rarely, uveal melanoma may harbor double mutations in GNAQ and/or GNA11. Recent data imply, that implementation of GNAQ/GNA11 mutation analysis in routine diagnostic procedures might be helpful for future therapeutic decisions.

[Unilateral multifocal uveal melanoma (a clinical and genetic study)]. / Monolateral'naia mul'tifokal'naia uveal'naia melanoma (kliniko-geneticheskoe issledovanie).

The study presents clinical and genetic analysis of a case of unilateral multifocal uveal choroidal melanoma in a patient of 67 years. Results of ophthalmoscopy, echography, fluorescent angiography, optical coherence tomography are described. Molecular genetic testing of peripheral blood samples was performed, including detection of the occurrences of CC genotype in C3435T polymorphism of the gene ABCB1/MDR1 associated with unfavorable vital prognosis. Analysis of the genes GNAQ and GNA11 revealed two mutually exclusive mutations in the genes GNAQG183A and GNAQA209C showing genetic heterogeneity of the two tumor lesions. Organ preservation treatment of unilateral multifocal uveal melanoma was proven possible with brachytherapy method. Uveal melanoma with multicentric growth is of interest to ophthalmologists because it requires differential diagnostics from a variety of diseases including metastases in the choroid, such as metastases of uveal melanoma and skin melanoma, as well as other intraocular neoplasms.

Oncogenic signaling in uveal melanoma.

Uveal melanoma is the most common primary cancer of the eye, and despite rapidly emerging insights into the molecular profile of this disease, prognosis of patients with metastatic uveal melanoma remains poor with mortality rates unchanged in over 35 years. Early genetic events activate G protein-coupled receptor signaling in nearly all uveal tumors via mutually exclusive mutations in the GNAQ, GNA11, CYSLTR2, or PLCB4 genes. A multitude of signaling cascades downstream of G protein activation, including protein kinase C and mitogen-activated protein kinase activity, are actionable, and many ongoing clinical trials are targeting these pathways. Additional cytogenetic and genetic changes, however, including chromosome 3 monosomy, mutations in the BAP1 tumor suppressor gene, alterations in the splicing factors SRSF2/SF3B1, and mutations in the translation initiation factor EIF1AX, modulate signaling output in uveal tumors and modify the risk of metastases. Here, we review the complex interactions between genetic, molecular signaling, and prognostic profiles in uveal melanoma; the clinical implications of these interactions; and the latest potential targets for rational therapy.

BRAF, NRAS, KIT, TERT, GNAQ/GNA11 mutation profile analysis of head and neck mucosal melanomas: a study of 42 cases.

Head and neck mucosal melanoma (HNMuM), which occurs mostly in the sinonasal and oral cavity, constitutes less than 1% of all malignant melanomas. Treatment options fail to improve the prognosis of this aggressive tumour that has low overall survival rates. Thus, development of new targeted therapies is essential. Unfortunately, limited data exist regarding their molecular profile. BRAF, NRAS, KIT, TERT and GNAQ/GNA11 oncogene mutations were investigated in 42 HNMuMs (28 sinonasal, 13 oral, 1 nasopharyngeal). Mutation rates were as follows: BRAF (4.8%), NRAS (4.8%), KIT (9.5%), TERT (7.5%), GNAQ/GNA11 (0%). Among 11 cases that harboured mutations (26%), 10 (91%) were located in sinonasal and one (9%) in the oral cavity. The literature was reviewed with comparison of frequencies based on the gathered data. NRAS and TERT promoter mutation rates were significantly higher in sinonasal than in oral location (p<0.05). Our results indicated that BRAF, NRAS, KIT, TERT and GNAQ/GNA11 gene mutations occur at low frequencies in HNMuMs, and subgroups (oral versus sinonasal) differ in their molecular profile. Low rates of aforementioned mutations and activation of oncogenes by pathways other than sun exposure support the distinctive nature of HNMuMs with regard to their cutaneous counterparts.

BRAF, GNAQ, and GNA11 mutations and copy number in pediatric low-grade glioma.

Fifty-two samples of pediatric low-grade glioma (48 primary, 4 recurrent) were analyzed for BRAF copy number variation (digital PCR analysis, CopyCaller) and point mutations of BRAF V600E, and exon 5 Q209 in GNAQ, and GNA11, using the MALDI-TOF mass spectrometer with validation by direct sequencing. An increased BRAF copy number was found in 18/47 primary samples tested; 15 of them (83.3%) were pilocytic astrocytomas. A BRAF mutation was found in 3/48 primary tumors, all with a normal BRAF copy number and no GNAQ mutation. One sample had a GNAQ209 mutation (Q209P626) with a normal BRAF gene; none of the tumors had a GNA11Q209 mutation. Recurrent or progressive tumors, analyzed in four patients, had the same molecular genotype as their primary. Increased BRAF copy number and activating BRAF mutations may be involved in the development of low-grade glioma via overactivation of the Ras/Raf pathway. This is the first report of a mutation in GNAQ209 in pediatric low-grade glioma. Understanding the molecular mechanisms underlying glioma initiation and growth may assist in the development of targeted therapies.