GNAQ

Gene Summary

Gene:GNAQ; G protein subunit alpha q
Aliases: GAQ, SWS, CMC1, G-ALPHA-q
Location:9q21.2
Summary:This locus encodes a guanine nucleotide-binding protein. The encoded protein, an alpha subunit in the Gq class, couples a seven-transmembrane domain receptor to activation of phospolipase C-beta. Mutations at this locus have been associated with problems in platelet activation and aggregation. A related pseudogene exists on chromosome 2.[provided by RefSeq, Nov 2010]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:guanine nucleotide-binding protein G(q) subunit alpha
Source:NCBIAccessed: 15 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Melanoma
  • Genetic Predisposition
  • Ubiquitin Thiolesterase
  • Thyroid Nodule
  • Missense Mutation
  • Treatment Failure
  • Antineoplastic Agents
  • Biomarkers, Tumor
  • Sensitivity and Specificity
  • rho GTP-Binding Proteins
  • Phosphoproteins
  • Tissue Fixation
  • Sturge-Weber Syndrome
  • Phenotype
  • Visual Acuity
  • GTP Phosphohydrolases
  • Melanocytes
  • Cancer DNA
  • Adolescents
  • Xenograft Models
  • Nevus, Blue
  • Chromosome 9
  • Up-Regulation
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Eye Cancer
  • DNA Mutational Analysis
  • Uveal Neoplasms
  • High-Throughput Nucleotide Sequencing
  • Mutation
  • Apoptosis
  • Translational Medical Research
  • GTP-Binding Protein alpha Subunits
  • Terminology as Topic
  • Tumor Suppressor Proteins
  • Membrane Proteins
  • Molecular Targeted Therapy
  • Neoplasm Metastasis
  • Spinal Cord Neoplasms
  • GNAQ
  • Cancer Gene Expression Regulation
  • Proto-Oncogene Proteins c-kit
  • FGFR1
Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: GNAQ (cancer-related)

Amann VC, Ramelyte E, Thurneysen S, et al.
Developments in targeted therapy in melanoma.
Eur J Surg Oncol. 2017; 43(3):581-593 [PubMed] Related Publications
Melanomas are disease entities driven in part by the mitogen activated protein kinase (MAPK) pathway. The TCGA network recently defined four genetic subtypes based on the most prevalent significantly mutated genes, including mutant BRAF, mutant RAS (N/H/K), mutant NF1, and Triple wild-type melanoma (harboring none of the aforementioned mutations, but instead includes KIT, GNA and GNAQ mutations). The successful development of kinase inhibitors marked a milestone in the treatment of metastatic melanoma. Combination treatment with a BRAF- and MEK-inhibitor is the current standard of care for inoperable stage IIIC/IV BRAF-mutated melanoma. Recent data demonstrate excellent long-term outcome, especially in patients with normal baseline LDH levels, and confirm that there is a subset of BRAF inhibitor-naive patients who experience durable responses without progression on combination treatment. In the future, adding a third compound based on individual genetic alterations might further improve the outcome of targeted therapy.

Marjanovic I, Kostic J, Stanic B, et al.
Parallel targeted next generation sequencing of childhood and adult acute myeloid leukemia patients reveals uniform genomic profile of the disease.
Tumour Biol. 2016; 37(10):13391-13401 [PubMed] Related Publications
The age-specific differences in the genetic mechanisms of myeloid leukemogenesis have been observed and studied previously. However, NGS technology has provided a possibility to obtain a large amount of mutation data. We analyzed DNA samples from 20 childhood (cAML) and 20 adult AML (aAML) patients, using NGS targeted sequencing. The average coverage of high-quality sequences was 2981 × per amplicon. A total of 412 (207 cAML, 205 aAML) variants in the coding regions were detected; out of which, only 122 (62 cAML and 60 aAML) were potentially protein-changing. Our results confirmed that AML contains small number of genetic alterations (median 3 mutations/patient in both groups). The prevalence of the most frequent single gene AML associated mutations differed in cAML and aAML patient cohorts: IDH1 (0 % cAML, 5 % aAML), IDH2 (0 % cAML, 10 % aAML), NPM1 (10 % cAML, 35 % aAML). Additionally, potentially protein-changing variants were found in tyrosine kinase genes or genes encoding tyrosine kinase associated proteins (JAK3, ABL1, GNAQ, and EGFR) in cAML, while among aAML, the prevalence is directed towards variants in the methylation and histone modifying genes (IDH1, IDH2, and SMARCB1). Besides uniform genomic profile of AML, specific genetic characteristic was exclusively detected in cAML and aAML.

Tang T, Eldabaje R, Yang L
Current Status of Biological Therapies for the Treatment of Metastatic Melanoma.
Anticancer Res. 2016; 36(7):3229-41 [PubMed] Related Publications
Compared to early-stage melanoma when surgical excision is possible, metastatic disease continues to offer a much grimmer prognosis as traditional chemotherapy treatment regimens offer relatively little survival benefit. This has led to changes in treatment approaches over the preceding two decades as contemporary methods for the treatment of advanced or metastatic melanoma now involve a number of biological modalities, which include immunotherapeutic approaches, targeted therapies and epigenetic modification therapies. Clinically available immunotherapeutic agents include interleukin 2 (IL-2), as well as drugs targeting the important immune checkpoint molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1). The targeted therapeutic agents modulate specific pro-oncogenic mutations such as v-Raf murine sarcoma viral oncogene homolog B (BRAF), receptor tyrosine kinases, MEK inhibitors and potential future therapeutic targets, such as the CDK4/CDK6, PTEN and GNAQ/GNA11 genes. Additionally, an increasing understanding of the role of epigenetic alterations in the development and progression of melanoma now offers a new potential drug target. Several of these agents have shown promising results; however, in many investigations, combinations of different therapeutic approaches, each with different mechanisms of action, have yielded improved outcomes as treatment regimens continue to be further optimized by active research and patient disease sub-group analyses. This review summarizes the novel biological agents and new treatments, directly contributing to the significant improvement of biological therapies and markedly advancing knowledge of clinical application of newly approved and developed therapies in treatment of patients with metastatic melanoma.

Gamsizkan M, Yilmaz I, Simsek HA, et al.
Mutation analysis of metastatic melanomas in the central nervous system: results of a panel of 5 genes in 48 cases.
Clin Neuropathol. 2016 Jul-Aug; 35(4):178-85 [PubMed] Related Publications
Melanocytic lesions in the central nervous system (CNS) may be primary to the site but are more commonly metastases from cutaneous primaries. In fact, melanomas are one of the most common malignancies that can metastasize to the brain, and some patients may not have a diagnosis of melanoma prior to the discovery of the CNS lesion. In such cases, identifying the primary site may be challenging. We reviewed the archives of a large referral center for melanocytic tumors involving the CNS and selected 48 patients for this study based on our inclusion criteria. We used sequencing to identify mutation status of these tumors and compared these with clinicopathological features. Mutations in exon 9, 11, 13, 17, and 18 of KIT gene, exon 15 of BRAF gene, exon 2 and 3 of NRAS gene, exon 4 and 5 of GNAQ and GNA11 genes were analyzed. Mutations in BRAF-exon 15 were the most common among tumors (58.3%). NRAS-exon 2 and NRAS-exon 3 mutations were detected in 3 and 7 cases, respectively. GNAQ-exon 4, GNAQ-exon 5 and GNA11-exon 5 mutation were present in 1 tumor each. Eight tumors were wild type for all 5 genes, and 6 of these were not known primary despite a work-up and clinical follow-up. Only 1 of these tumors showed a mutation in exon 11 of KIT gene. When compared to primary melanocytic lesions of the CNS, metastatic melanomas were characterized by BRAF gene mutations and wild-type GNAQ and GNA11 genes.

Yavuzyigitoglu S, Mensink HW, Smit KN, et al.
Metastatic Disease in Polyploid Uveal Melanoma Patients Is Associated With BAP1 Mutations.
Invest Ophthalmol Vis Sci. 2016; 57(4):2232-9 [PubMed] Related Publications
PURPOSE: Most of the uvea melanoma (UM) display a near-diploid (normal, -2N) karyotype with only a few chromosomal changes. In contrast to these simple aberrations 18% of the UM samples show a polyploid character (>2N) and this was associated with an unfavorable prognosis. This study attempts to gain insight in the prognostic value of polyploidy in UM.
METHODS: In 202 patients the ploidy status of the UM was determined using cytogenetic analysis, fluorescence-in-situ-hybridization (FISH), multiplex ligation dependent probe amplification (MLPA), and/or single nucleotide polymorphism (SNP) array analysis. Immunohistochemistry was used to determine the BAP1 expression and mutation analyses of BAP1 (coding regions) and the mutation hotspots for the SF3B1, EIF1AX, GNAQ, and GNA11 genes was carried out using Sanger sequencing or whole-exome sequencing.
RESULTS: Twenty-three patients had a polyploid UM karyotype (11.4%). Patients with a polyploid tumor had larger tumors (15.61 vs. 13.13 mm, P = 0.004), and more often loss of heterozygosity of chromosome 3 (P = 0.003). No difference in occurrence of mutations between polyploid and diploid tumors was observed for BAP1, SF3B1, EIF1AX, GNAQ, and GNA11. Polyploidy did not affect survival (P = 0.143). BAP1 deficiency was the only significant independent prognostic predictor for patients with polyploid tumors, with a 16-fold increased hazard ratio (HR 15.90, P = 0.009).
CONCLUSIONS: The prevalence of mutations in the UM related genes is not different in polyploid UM compared with diploid UM. Moreover, similar to patients with diploid UM, BAP1 mutation is the most significant prognostic predictor of metastasis in patients with polyploid UM.

Ayturk UM, Couto JA, Hann S, et al.
Somatic Activating Mutations in GNAQ and GNA11 Are Associated with Congenital Hemangioma.
Am J Hum Genet. 2016; 98(4):789-95 [PubMed] Free Access to Full Article Related Publications
Congenital hemangioma is a rare vascular tumor that forms in utero. Postnatally, the tumor either involutes quickly (i.e., rapidly involuting congenital hemangioma [RICH]) or partially regresses and stabilizes (i.e., non-involuting congenital hemangioma [NICH]). We hypothesized that congenital hemangiomas arise due to somatic mutation and performed massively parallel mRNA sequencing on affected tissue from eight participants. We identified mutually exclusive, mosaic missense mutations that alter glutamine at amino acid 209 (Glu209) in GNAQ or GNA11 in all tested samples, at variant allele frequencies (VAF) ranging from 3% to 33%. We verified the presence of the mutations in genomic DNA using a combination of molecular inversion probe sequencing (MIP-seq) and digital droplet PCR (ddPCR). The Glu209 GNAQ and GNA11 missense variants we identified are common in uveal melanoma and have been shown to constitutively activate MAPK and/or YAP signaling. When we screened additional archival formalin-fixed paraffin-embedded (FFPE) congenital cutaneous and hepatic hemangiomas, 4/8 had GNAQ or GNA11 Glu209 variants. The same GNAQ or GNA11 mutation is found in both NICH and RICH, so other factors must account for these tumors' different postnatal behaviors.

Uchiyama Y, Nakashima M, Watanabe S, et al.
Ultra-sensitive droplet digital PCR for detecting a low-prevalence somatic GNAQ mutation in Sturge-Weber syndrome.
Sci Rep. 2016; 6:22985 [PubMed] Free Access to Full Article Related Publications
Droplet digital PCR (ddPCR), a method for measuring target nucleic acid sequence quantity, is useful for determining somatic mutation rates using TaqMan probes. In this study, the detection limit of copy numbers of test DNA by ddPCR was determined based on Poisson distribution. Peptide nucleic acid (PNA), which strongly hybridises to target lesions, can inhibit target amplification by PCR. Therefore, by combination of PCR with PNA and ddPCR (PNA-ddPCR), the detection limit could be lowered. We reanalysed a somatic GNAQ mutation (c.548G > A) in patients with Sturge-Weber syndrome (SWS) using ddPCR and PNA-ddPCR. Importantly, among three patients previously found to be mutation negative by next-generation sequencing, two patients had the GNAQ mutation with a mutant allele frequency of less than 1%. Furthermore, we were able to find the same mutation in blood leukocyte or saliva DNA derived from four out of 40 SWS patients. Vascular anomalies and blood leukocytes originate from endothelial cells and haemangioblasts, respectively, which are both of mesodermal origin. Therefore, blood leukocytes may harbour the GNAQ mutation, depending on the time when the somatic mutation is acquired. These data suggest the possibility of diagnosis using blood DNA in some patients with SWS.

Griewank KG, Schilling B, Scholz SL, et al.
Oncogene status as a diagnostic tool in ocular and cutaneous melanoma.
Eur J Cancer. 2016; 57:112-7 [PubMed] Related Publications
The majority of human tumours can be easily and correctly diagnosed based on clinical information and pathological assessment. In some cases however, correct diagnosis can prove difficult. In such cases, molecular approaches can be of significant diagnostic value. In recent years, the understanding of genetic alterations has greatly increased. In cutaneous melanoma, it is now well recognised, that 70-80% of tumours harbour BRAF and NRAS mutations. These mutations never occur in uveal melanoma. On the other hand activating GNAQ and GNA11 mutations are found in ∼90% of uveal melanomas, and are exceptionally rare in other melanomas (<1%). Here, we demonstrate a number of melanoma cases, where distinguishing if a tumour was of cutaneous or ocular origin was not possible based on clinical and pathological assessment. In these cases there was either atypical clinical presentation or metastasis of unclear primary. Histological distinction between uveal and cutaneous melanomas, especially at the stage of metastasis, is not reliable as they can be morphologically very similar. In all cases we present, a simple genetic assessment of oncogene mutation status was able to clearly define the melanoma type. This type of genetic assessment is of great diagnostic value and due to its simplicity could be performed in routine clinical practice even in smaller institutions.

Thomas AC, Zeng Z, Rivière JB, et al.
Mosaic Activating Mutations in GNA11 and GNAQ Are Associated with Phakomatosis Pigmentovascularis and Extensive Dermal Melanocytosis.
J Invest Dermatol. 2016; 136(4):770-8 [PubMed] Free Access to Full Article Related Publications
Common birthmarks can be an indicator of underlying genetic disease but are often overlooked. Mongolian blue spots (dermal melanocytosis) are usually localized and transient, but they can be extensive, permanent, and associated with extracutaneous abnormalities. Co-occurrence with vascular birthmarks defines a subtype of phakomatosis pigmentovascularis, a group of syndromes associated with neurovascular, ophthalmological, overgrowth, and malignant complications. Here, we discover that extensive dermal melanocytosis and phakomatosis pigmentovascularis are associated with activating mutations in GNA11 and GNAQ, genes that encode Gα subunits of heterotrimeric G proteins. The mutations were detected at very low levels in affected tissues but were undetectable in the blood, indicating that these conditions are postzygotic mosaic disorders. In vitro expression of mutant GNA11(R183C) and GNA11(Q209L) in human cell lines demonstrated activation of the downstream p38 MAPK signaling pathway and the p38, JNK, and ERK pathways, respectively. Transgenic mosaic zebrafish models expressing mutant GNA11(R183C) under promoter mitfa developed extensive dermal melanocytosis recapitulating the human phenotype. Phakomatosis pigmentovascularis and extensive dermal melanocytosis are therefore diagnoses in the group of mosaic heterotrimeric G-protein disorders, joining McCune-Albright and Sturge-Weber syndromes. These findings will allow accurate clinical and molecular diagnosis of this subset of common birthmarks, thereby identifying infants at risk for serious complications, and provide novel therapeutic opportunities.

Küsters-Vandevelde HV, Creytens D, van Engen-van Grunsven AC, et al.
SF3B1 and EIF1AX mutations occur in primary leptomeningeal melanocytic neoplasms; yet another similarity to uveal melanomas.
Acta Neuropathol Commun. 2016; 4:5 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: Like uveal melanomas, primary leptomeningeal melanocytic neoplasms (LMNs) frequently carry GNAQ and GNA11 mutations. However, it is currently unknown whether these LMNs harbor mutations in BAP1, SF3B1 and/or EIF1AX like uveal melanomas as well. In this study, we used Sanger sequencing for the detection of mutations in SF3B1 (hotspots in exon 14 and 15) and EIF1AX (exon 1 and 2 and flanking intronic regions) in a series of 24 primary LMNs. Additionally, BAP1 immunohistochemistry was used as a surrogate marker for the detection of inactivating mutations in the BAP1 gene.
RESULTS: Mutations in either SF3B1 or EIF1AX were identified in 8 out of 24 primary LMNs (33 %). The presence of these mutations was mutually exclusive and occurred in primary LMNs of different malignancy grades (melanocytomas, intermediate-grade melanocytic tumors, melanomas). Complete absence of nuclear BAP1 staining as is typically seen in BAP1-mutated tumors was not observed.
CONCLUSIONS: Our finding that an SF3B1 or EIF1AX mutation is present in a substantial subset of primary LMNs underscores that these tumors genetically resemble uveal melanoma and are different from cutaneous melanoma at the genetic level. This information may not only aid in the differential diagnosis of primary versus metastatic melanocytic tumor in/around the central nervous system, but also in the identification of more promising therapeutic approaches targeting the molecular pathways involved in the oncogenesis of LMNs. As none of the primary LMNs in our series showed complete loss of nuclear BAP1 protein, it is unlikely that BAP1 mutations are frequent in these tumors but the role of this gene warrants further investigation.

van de Nes J, Gessi M, Sucker A, et al.
Targeted next generation sequencing reveals unique mutation profile of primary melanocytic tumors of the central nervous system.
J Neurooncol. 2016; 127(3):435-44 [PubMed] Related Publications
Melanocytic tumors originating in the central nervous system (MT-CNS) are rare tumors that generally have a favorable prognosis, however malignant tumors do occur. Pathogenetically MT-CNS are not well characterized. Similar to uveal melanoma and blue nevi, they frequently harbor activating GNAQ or GNA11 mutations. Rare NRAS mutations have also been reported. Other mutations have not yet been described. We analyzed 19 MT-CNS, 7 uveal melanomas and 19 cutaneous melanomas using a targeted next generation sequencing approach analyzing 29 genes known to be frequently mutated in other melanocytic tumors (in particular uveal and cutaneous melanomas). In concordance with previous studies, cutaneous melanoma samples showed frequent NRAS or BRAF mutations, as well as mutations in other genes (e.g. NF1, RAC1, PIK3CA, ARID1A). Metastasized uveal melanomas exhibited mutations in GNAQ, GNA11 and BAP1. In contrast, MT-CNS almost exclusively demonstrated mutations in GNAQ (71 %) or GNA11 (12 %). Interestingly both GNA11 mutations identified were detected in MT-CNS diagnosed as intermediate grade melanocytomas which also recurred. One of these recurrent cases also harbored an inactivating BAP1 mutation and was found to have lost one copy of chromosome 3. Our findings show that while MT-CNS do have GNAQ or GNA11 mutations, they rarely harbor other recurrent mutations found in uveal or cutaneous melanomas. Considering chromosome 3 and BAP1 loss are robust markers of poor prognosis in uveal melanoma, it will prove interesting to determine whether these genomic alterations are also of prognostic significance in MT-CNS.

Chan MP, Andea AA, Harms PW, et al.
Genomic copy number analysis of a spectrum of blue nevi identifies recurrent aberrations of entire chromosomal arms in melanoma ex blue nevus.
Mod Pathol. 2016; 29(3):227-39 [PubMed] Related Publications
Blue nevi may display significant atypia or undergo malignant transformation. Morphologic diagnosis of this spectrum of lesions is notoriously difficult, and molecular tools are increasingly used to improve diagnostic accuracy. We studied copy number aberrations in a cohort of cellular blue nevi, atypical cellular blue nevi, and melanomas ex blue nevi using Affymetrix's OncoScan platform. Cases with sufficient DNA were analyzed for GNAQ, GNA11, and HRAS mutations. Copy number aberrations were detected in 0 of 5 (0%) cellular blue nevi, 3 of 12 (25%) atypical cellular blue nevi, and 6 of 9 (67%) melanomas ex blue nevi. None of the atypical cellular blue nevi displayed more than one aberration, whereas complex aberrations involving four or more regions were seen exclusively in melanomas ex blue nevi. Gains and losses of entire chromosomal arms were identified in four of five melanomas ex blue nevi with copy number aberrations. In particular, gains of 1q, 4p, 6p, and 8q, and losses of 1p and 4q were each found in at least two melanomas. Whole chromosome aberrations were also common, and represented the sole finding in one atypical cellular blue nevus. When seen in melanomas, however, whole chromosome aberrations were invariably accompanied by partial aberrations of other chromosomes. Three melanomas ex blue nevi harbored aberrations, which were absent or negligible in their precursor components, suggesting progression in tumor biology. Gene mutations involving GNAQ and GNA11 were each detected in two of eight melanomas ex blue nevi. In conclusion, copy number aberrations are more common and often complex in melanomas ex blue nevi compared with cellular and atypical cellular blue nevi. Identification of recurrent gains and losses of entire chromosomal arms in melanomas ex blue nevi suggests that development of new probes targeting these regions may improve detection and risk stratification of these lesions.

Vivancos A, Caratú G, Matito J, et al.
Genetic evolution of nevus of Ota reveals clonal heterogeneity acquiring BAP1 and TP53 mutations.
Pigment Cell Melanoma Res. 2016; 29(2):247-53 [PubMed] Related Publications
Melanoma presents molecular alterations based on its anatomical location and exposure to environmental factors. Due to its intrinsic genetic heterogeneity, a simple snapshot of a tumor's genetic alterations does not reflect the tumor clonal complexity or specific gene-gene cooperation. Here, we studied the genetic alterations and clonal evolution of a unique patient with a Nevus of Ota that developed into a recurring uveal-like dermal melanoma. The Nevus of Ota and ulterior lesions contained GNAQ mutations were c-KIT positive, and tumors showed an increased RAS pathway activity during progression. Whole-exome sequencing of these lesions revealed the acquisition of BAP1 and TP53 mutations during tumor evolution, thereby unmasking clonal heterogeneity and allowing the identification of cooperating genes within the same tumor. Our results highlight the importance of studying tumor genetic evolution to identify cooperating mechanisms and delineate effective therapies.

Johansson P, Aoude LG, Wadt K, et al.
Deep sequencing of uveal melanoma identifies a recurrent mutation in PLCB4.
Oncotarget. 2016; 7(4):4624-31 [PubMed] Free Access to Full Article Related Publications
Next generation sequencing of uveal melanoma (UM) samples has identified a number of recurrent oncogenic or loss-of-function mutations in key driver genes including: GNAQ, GNA11, EIF1AX, SF3B1 and BAP1. To search for additional driver mutations in this tumor type we carried out whole-genome or whole-exome sequencing of 28 tumors or primary cell lines. These samples have a low mutation burden, with a mean of 10.6 protein changing mutations per sample (range 0 to 53). As expected for these sun-shielded melanomas the mutation spectrum was not consistent with an ultraviolet radiation signature, instead, a BRCA mutation signature predominated. In addition to mutations in the known UM driver genes, we found a recurrent mutation in PLCB4 (c.G1888T, p.D630Y, NM_000933), which was validated using Sanger sequencing. The identical mutation was also found in published UM sequence data (1 of 56 tumors), supporting its role as a novel driver mutation in UM. PLCB4 p.D630Y mutations are mutually exclusive with mutations in GNA11 and GNAQ, consistent with PLCB4 being the canonical downstream target of the former gene products. Taken together these data suggest that the PLCB4 hotspot mutation is similarly a gain-of-function mutation leading to activation of the same signaling pathway, promoting UM tumorigenesis.

Costa S, Byrne M, Pissaloux D, et al.
Melanomas Associated With Blue Nevi or Mimicking Cellular Blue Nevi: Clinical, Pathologic, and Molecular Study of 11 Cases Displaying a High Frequency of GNA11 Mutations, BAP1 Expression Loss, and a Predilection for the Scalp.
Am J Surg Pathol. 2016; 40(3):368-77 [PubMed] Related Publications
Melanomas associated with blue nevi (MABN) or mimicking cellular blue nevi (MMCBN) represent exceptional variants of malignant cutaneous melanocytic tumors. Uveal and leptomeningeal melanomas frequently have somatic mutations of GNAQ or GNA11, which are believed to be early driver mutations. In uveal melanomas, monosomy 3, linked to the BAP1 gene, is an adverse prognostic factor. We have studied the clinical, histologic, BAP1 expression profile, and molecular data of 11 cases of MABN/MMCBN and 24 cellular blue nevi. Most of the cases of MABN/MMCBN occurred on the scalps of adult patients and presented as rapidly growing nodules, typically >1 cm, often arising at the site of a preexisting melanocytic lesion. The MABN/MMCBN were composed of dense nests of large dermal atypical melanocytes, in some cases lying adjacent to a blue nevus. Four patients developed metastatic disease, and 2 died from their disease. A GNA11 mutation was found in 8/11 cases and a GNAQ mutation in 1 case. Seven of 11 cases showed loss of nuclear BAP1 immunohistochemical (IHC) expression in the malignant component, sparing the adjacent nevus. Array comparative genomic hybridization revealed recurrent deletions of chromosomes 1p, 3p, 4q, 6q, 8p, 16q, and 17q and recurrent gains of chromosomes 6p, 8q, and 21q. The 24 cases of cellular blue nevi frequently occurred on the sacrum, had GNAQ mutations, and showed normal positive IHC staining for BAP1. These results underscore overlapping features in all blue-like malignant melanocytic tumors. Loss of BAP1 IHC expression was restricted to melanomas, including all metastatic cases.

Shoushtari AN, Carvajal RD
Treatment of Uveal Melanoma.
Cancer Treat Res. 2016; 167:281-93 [PubMed] Related Publications
Uveal melanoma (UM) comprises approximately 5 % of all melanoma diagnoses in the USA each year. Approximately half of patients with UM eventually develop metastases, most commonly involving the liver. Historically, prognosis for these patients has been poor, with death occurring 6-12 months from the time of metastases. Multiple trials of cytotoxic treatments largely extrapolated from cutaneous melanoma have been ineffective in metastatic UM. Trials of regional hepatic-directed therapy have led to high response rates, but these have yet to be translated into a survival benefit. Recently, it was discovered that the majority of UMs harbor activating mutations in genes encoding one of two G-alpha protein subunits, GNAQ and GNA11. This knowledge has led to the rational development of clinical trials specifically for UM utilizing targeted inhibitors of the activated signaling pathways such as mitogen-activated protein kinase, Akt, and protein kinase C. A recent trial of the oral MEK inhibitor selumetinib was the first to show clinical benefit for any systemic therapy in a randomized fashion. This increasing understanding of the biology of UM offers hope that novel treatments will continue to benefit patients with metastatic disease.

Lyu J, Wu Y, Li C, et al.
Mutation scanning of BRAF, NRAS, KIT, and GNAQ/GNA11 in oral mucosal melanoma: a study of 57 cases.
J Oral Pathol Med. 2016; 45(4):295-301 [PubMed] Related Publications
BACKGROUND: Recent advances in novel targeted therapies have created the need for molecular characterization of cancer to allow accurate personalized treatments. In this study, our aim was to investigate the incidence of activating mutations of oncogenes BRAF, NRAS, KIT, and GNAQ/GNA11 in oral mucosal melanoma.
METHODS: We analyzed a cohort of 57 oral mucosal melanoma samples, including 27 frozen samples and 30 formalin-fixed paraffin-embedded samples. The tumors were screened for hotspot mutations of BRAF (exon 15), NRAS (exons 2 and 3), KIT (exons 9, 11, 13, and 17), and GNAQ/GNA11 (exon 5) by high-resolution melting and direct sequencing.
RESULTS: In oral mucosal melanoma, 7.0% of tumors harbored KIT mutations and 3.5% harbored BRAF mutations, while classic BRAF V600E mutation was not detected. We found no mutations of NRAS or GNAQ/GNA11 in oral mucosal melanoma.
CONCLUSION: We demonstrated that driver mutations are rare in mutational hotspots of BRAF, NRAS, KIT, and GNAQ/GNA11 in oral mucosal melanoma. The majority of patients will not benefit from KIT and BRAF inhibitors.

Ambrosini G, Sawle AD, Musi E, Schwartz GK
BRD4-targeted therapy induces Myc-independent cytotoxicity in Gnaq/11-mutatant uveal melanoma cells.
Oncotarget. 2015; 6(32):33397-409 [PubMed] Free Access to Full Article Related Publications
Uveal melanoma (UM) is an aggressive intraocular malignancy with limited therapeutic options. Both primary and metastatic UM are characterized by oncogenic mutations in the G-protein alpha subunit q and 11. Furthermore, nearly 40% of UM has amplification of the chromosomal arm 8q and monosomy of chromosome 3, with consequent anomalies of MYC copy number. Chromatin regulators have become attractive targets for cancer therapy. In particular, the bromodomain and extra-terminal (BET) inhibitor JQ1 has shown selective inhibition of c-Myc expression with antiproliferative activity in hematopoietic and solid tumors. Here we provide evidence that JQ1 had cytotoxic activity in UM cell lines carrying Gnaq/11 mutations, while in cells without the mutations had little effects. Using microarray analysis, we identified a large subset of genes modulated by JQ1 involved in the regulation of cell cycle, apoptosis and DNA repair. Further analysis of selected genes determined that the concomitant silencing of Bcl-xL and Rad51 represented the minimal requirement to mimic the apoptotic effects of JQ1 in the mutant cells, independently of c-Myc. In addition, administration of JQ1 to mouse xenograft models of Gnaq-mutant UM resulted in significant inhibition of tumor growth.Collectively, our results define BRD4 targeting as a novel therapeutic intervention against UM with Gnaq/Gna11 mutations.

Shim U, Kim HN, Lee H, et al.
Pathway Analysis Based on a Genome-Wide Association Study of Polycystic Ovary Syndrome.
PLoS One. 2015; 10(8):e0136609 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age, and it is affected by both environmental and genetic factors. Although the genetic component of PCOS is evident, studies aiming to identify susceptibility genes have shown controversial results. This study conducted a pathway-based analysis using a dataset obtained through a genome-wide association study (GWAS) to elucidate the biological pathways that contribute to PCOS susceptibility and the associated genes.
METHODS: We used GWAS data on 636,797 autosomal single nucleotide polymorphisms (SNPs) from 1,221 individuals (432 PCOS patients and 789 controls) for analysis. A pathway analysis was conducted using meta-analysis gene-set enrichment of variant associations (MAGENTA). Top-ranking pathways or gene sets associated with PCOS were identified, and significant genes within the pathways were analyzed.
RESULTS: The pathway analysis of the GWAS dataset identified significant pathways related to oocyte meiosis and the regulation of insulin secretion by acetylcholine and free fatty acids (all nominal gene-set enrichment analysis (GSEA) P-values < 0.05). In addition, INS, GNAQ, STXBP1, PLCB3, PLCB2, SMC3 and PLCZ1 were significant genes observed within the biological pathways (all gene P-values < 0.05).
CONCLUSIONS: By applying MAGENTA pathway analysis to PCOS GWAS data, we identified significant pathways and candidate genes involved in PCOS. Our findings may provide new leads for understanding the mechanisms underlying the development of PCOS.

Singh AD, Schoenfield LA, Bastian BC, et al.
Congenital uveal melanoma?
Surv Ophthalmol. 2016 Jan-Feb; 61(1):59-64 [PubMed] Related Publications
A 3-month-old infant with a white mother and Asian father presented with discoloration and prominence of the left eye since birth. Examination revealed a normal right eye. The left eye had hyperchromic heterochromia and an enlarged cornea (diameter, 13.0 mm) with intraocular pressure of 26 mm Hg. There were multiple areas of subconjunctival nodular pigmentation that extended posteriorly into the superior fornix. Fundus examination showed a large ciliochoroidal pigmented mass extending from 10:30 to 3:00 o'clock position involving the superior half of the choroid and adjacent ciliary body. The eye was enucleated, confirming the diagnosis of diffuse uveal melanoma with extraocular extension. Systemic surveillance (hepatic panel and ultrasonography of the liver) performed every 6 months for 5 years was has been negative for metastases. The tumor was investigated intensively for the panel of genes (BAP1, BRAF, NRAS12, NRAS61, GNAQ, Kit 9,11,13,17,18) implicated in pathogenesis of blue nevus, cutaneous melanoma, and mucosal melanomas with negative results. Moreover, germline BAP1 mutation could not be identified. This case possibly represents as yet unidentified uveal melanocytic proliferation rather than a true variant of uveal melanoma.

Yilmaz I, Gamsizkan M, Kucukodaci Z, et al.
BRAF, KIT, NRAS, GNAQ and GNA11 mutation analysis in cutaneous melanomas in Turkish population.
Indian J Pathol Microbiol. 2015 Jul-Sep; 58(3):279-84 [PubMed] Related Publications
BACKGROUND: KIT and mitogen-activated protein kinase cascade are important for melanomagenesis. In the present study, we analyzed the frequency of BRAF, NRAS, KIT, GNAQ and GNA11 gene mutations and investigated their association with clinicopathological features of melanomas in Turkish population.
MATERIALS AND METHODS: Forty-seven primary cutaneous melanomas were included in our study. Sanger sequencing method was used for mutation analysis in all cases.
RESULTS: Mean age was 62.1 (29-101) years. Female:male ratio was 17:30. Among 47 melanomas, 14 (29.8%) BRAF, 10 (21.3%) NRAS, 4 (8.5%) KIT and 1(2.1%) GNAQ gene mutations were detected. Two of the KIT mutations were found in acral lentiginous melanoma (ALM). In the head and neck region, mutation frequency was significantly lower than in other locations (P = 0.035). The only GNAQ gene mutation (p.Q209L) was detected in a melanoma arising from blue nevus located on the scalp. None of the melanomas harbored NRAS exon 2, KIT exon 13/17/18, GNAQ exon 4 and GNA11 exon 4/5 mutations. Overall mutation frequency did not show significant difference between metastatic (8/14, 57.1%) and nonmetastatic (18/33, 54.5%) patients. We did not observe any significant association between mutation status and gender or age of various patients.
CONCLUSIONS: Our results support that BRAF and NRAS gene mutations are common in cutaneous melanomas. The activating mutations of KIT gene are rare and especially seen in ALM. GNAQ and GNA11 mutations are infrequent in cutaneous melanomas and may be associated only with melanomas arising from blue nevus.

Tse JY, Walls BE, Pomerantz H, et al.
Melanoma arising in a nevus of Ito: novel genetic mutations and a review of the literature on cutaneous malignant transformation of dermal melanocytosis.
J Cutan Pathol. 2016; 43(1):57-63 [PubMed] Related Publications
Dermal melanocytosis refers to a spectrum of benign melanocytic proliferations that includes Mongolian spot, nevus of Ota and nevus of Ito. These lesions most commonly occur in persons of Asian or African descent and are often present at birth or develop during childhood. Very rarely, dermal melanocytoses undergo malignant transformation. There have been only 13 reports in the literature of primary cutaneous melanoma arising in dermal melanocytoses. We report a case of a Chinese woman with melanoma arising in a congenital nevus of Ito. We performed targeted next-generation sequencing of the tumor which revealed mutations of GNAQ and BAP1, suggesting that alterations in these two genes led to malignant transformation of the nevus of Ito. We also provide a summary of reports in the literature regarding primary cutaneous melanoma arising in the context of dermal melanocytosis.

Van Beek JG, Koopmans AE, Vaarwater J, et al.
Metastatic disease in uveal melanoma: importance of a genetic profile?
Melanoma Res. 2015; 25(5):447-9 [PubMed] Related Publications
Mutation of SF3B1 has been identified in low-grade uveal melanoma with a good prognosis. In this study, we compare chromosomal aberrations and gene mutations between a primary uveal melanoma and its multiple hepatic and peripancreatic metastases. DNA was isolated from a large primary uveal melanoma after fractionated stereotactic radiotherapy and three distinct metastases (two liver samples and one peripancreatic lymph node) to perform single-nucleotide polymorphism array and fluorescent in-situ hybridization. We analyzed mutations in uveal melanoma target genes BAP1, GNAQ, GNA11, SF3B1, and EIF1AX. The primary tumor showed no abnormalities in chromosome 3, whereas metastases showed deletion of at least 3q12.1-q24 and the BAP1 gene was not mutated. All samples indicated the following consistent chromosomal aberrations: loss of 1p, gain of 6p, and gain of 8q. Subsequently, heterozygous SF3B1 and heterozygous GNA11 mutations were observed. The metastases showed more genetic aberrations than the primary tumor and may therefore represent the genetic status of the tumor before irradiation, whereas the current primary tumor shows presumably irradiation artifacts. An early occurring mutation in GNA11 was observed in all samples. The SF3B1 mutation seems to predispose for late metastatic disease in the absence of a BAP1 mutation.

Wiesner T, Kiuru M, Scott SN, et al.
NF1 Mutations Are Common in Desmoplastic Melanoma.
Am J Surg Pathol. 2015; 39(10):1357-62 [PubMed] Free Access to Full Article Related Publications
Desmoplastic melanoma (DM) is a rare variant of melanoma with distinct clinical, histopathologic, and immunohistochemical features. Clinically, DM differs from conventional melanoma by a higher propensity for local recurrence and less frequent metastatic spread to regional lymph nodes. In its pure form, DM has a distinct appearance displaying a low density of fusiform melanocytes in a collagen-rich matrix. Whereas a number of mutations have been identified in primary melanoma, including BRAF, NRAS, GNAQ, GNA11, and KIT, and the occurrence of these mutations has been found to correlate to some extent with the histopathologic features, anatomic site, and/or mode of sun exposure, no distinct set of mutations has so far been reported for DM. To study the potential association of neurofibromin (NF1) mutations with DM, we examined 15 desmoplastic and 20 non-DMs by next-generation sequencing. Mutations of the NF1 gene were found in 14 of 15 (93%) DMs and 4 of 20 (20%) non-DMs. The high frequency of NF1 mutations in DMs suggests an important role for NF1 in the biology of this type of melanoma.

Rodrigues MJ, Stern MH
Genetic landscape of uveal melanoma.
J Fr Ophtalmol. 2015; 38(6):522-5 [PubMed] Related Publications
Uveal melanoma is genetically one of the simplest malignant tumors in adults. Initiation of these tumors is dependent of an oncogenic mutation in the GNAQ or GNA11 genes present in almost all cases. The nature of second mutational events is of major interest as it monosomy 3, gain of 8q and BAP1 inactivation are associated with unfavorable prognosis while SF3BI or EIF1AX are of good prognosis. Despite their common lineage, cutaneous and uveal melanomas are distinct diseases, implicating different oncogenic pathways and contrasting mutational landscapes. Even if uveal melanoma is a simple tumor, it is also one of the deadliest tumors in adults. There is a major clinical need for drugs targeting either the downstream pathways of Gαq and Gα11 or the biological cell functions dysregulated by BAP1 loss of function.

Liu H, Lei C, Long K, et al.
Mutant GNAQ promotes cell viability and migration of uveal melanoma cells through the activation of Notch signaling.
Oncol Rep. 2015; 34(1):295-301 [PubMed] Related Publications
The occurrence of guanine nucleotide binding protein (G protein), q polypeptide (GNAQ) mutations has been found to be high in the majority of uveal melanomas. However, the underlying molecular mechanism of GNAQ mutations in modulating uveal melanoma is poorly understood. The aim of the present study was to investigate the role and underlying mechanism of mutant GNAQ in the regulation of cell viability and migration of uveal melanoma cells. Uveal melanoma cells containing mutant GNAQ were transfected with scrambled or GNAQ small-interfering RNA. Compared with the control, GNAQ knockdown markedly inhibited cell viability and migration. However, tumor cells without GNAQ mutations exhibited enhanced viability and migration following transfection with HA-GαqQL. Additionally, GNAQ knockdown significantly downregulated the expression of Jag-1 (Notch ligand), Notch intracellular domain and Hes-1 (Notch target gene) in uveal melanoma cells. Conversely, the GNAQ overexpression promoted their expression. Cell viability and migration induced by GNAQ was significantly inhibited following treatment with 5 µmol/l MRK003, a Notch signaling inhibitor. Furthermore, the transfection of human influenza hemagglutinin A epitope (HA)-GαqQL into tumor cells caused Yes-associated protein (YAP) dephosphorylation and nuclear translocation, which stimulated the expression of Jag-1 and Hes-1. Positive correlations were observed between the GNAQ and Jag-1 mRNA levels and between the GNAQ and Hes-1 mRNA levels. However, no positive correlation was observed between the GNAQ and YAP mRNA levels. The results suggested that GNAQ mutation induced viability and migration of uveal melanoma cells via Notch signaling activation, which is mediated by YAP dephosphorylation and nuclear translocation.

Shin D, Sinha M, Kondziolka DS, et al.
Intermediate-grade meningeal melanocytoma associated with nevus of Ota: a case report and review of the literature.
Melanoma Res. 2015; 25(4):273-8 [PubMed] Related Publications
Meningeal melanocytomas are rare melanin-producing tumors that are often found to be benign. However, a small subset of these tumors can present as intermediate-grade melanocytomas (IGMs) that have histopathological features that are between those of benign melanocytomas and malignant melanomas. IGMs have the potential to recur and metastasize or progress to a more histologically high grade melanoma. Melanocytomas appear to differ from primary and metastatic melanoma by their prolonged clinical course and they appear to have different driver mutations (i.e. mutation of GNAQ gene). The association of a meningeal melanocytoma with nevus of Ota is extremely rare. To our knowledge, there have been only 10 reported cases of synchronous occurrence and only one of the cases involved an IGM. We report the second case of intermediate-grade meningeal melanocytoma that is associated with congenital nevus of Ota. Histopathological work-up confirmed the intermediate grade of the lesion and a driver GNAQ mutation was identified consistent with previous reports.

Jahn SW, Kashofer K, Halbwedl I, et al.
Mutational dichotomy in desmoplastic malignant melanoma corroborated by multigene panel analysis.
Mod Pathol. 2015; 28(7):895-903 [PubMed] Related Publications
Desmoplastic malignant melanoma is a distinct melanoma entity histologically subtyped into mixed and pure forms due to significantly reduced lymph node metastases in the pure form. Recent reports investigating common actionable driver mutations have demonstrated a lack of BRAF, NRAS, and KIT mutation in pure desmoplastic melanoma. In search for alternative driver mutations next generation amplicon sequencing for hotspot mutations in 50 genes cardinal to tumorigenesis was performed and in addition the RET G691S polymorphism was investigated. Data from 21 desmoplastic melanomas (12 pure and 9 mixed) were retrieved. Pure desmoplastic melanomas were either devoid of mutations (50%) or displayed mutations in tumor suppressor genes (TP53, CDKN2A, and SMAD4) singularly or in combination with the exception of a PIK3CA double-mutation lacking established biological relevance. Mixed desmoplastic melanomas on the contrary were frequently mutated (89%), and 67% exhibited activating mutations similar to common-type cutaneous malignant melanomas (BRAF, NRAS, FGFR2, and ERBB2). Separate analysis of morphologically heterogeneous tumor areas in four mixed desmoplastic malignant melanomas displayed no difference in mutation status and RET G691 status. GNAQ and GNA11, two oncogenes in BRAF and NRAS wild-type uveal melanomas, were not mutated in our cohort. The RET G691S polymorphism was found in 25% of pure and 38% of mixed desmoplastic melanomas. Apart from RET G691S our findings demonstrate absence of activating driver mutations in pure desmoplastic melanoma beyond previously investigated oncogenes (BRAF, NRAS, and KIT). The findings underline the therapeutic dichotomy of mixed versus pure desmoplastic melanoma with regard to activating mutations primarily of the mitogen-activated protein kinase pathway.

Versluis M, de Lange MJ, van Pelt SI, et al.
Digital PCR validates 8q dosage as prognostic tool in uveal melanoma.
PLoS One. 2015; 10(3):e0116371 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Uveal melanoma (UM) development and progression is correlated with specific molecular changes. Recurrent mutations in GNAQ and GNA11 initiate UM development while tumour progression is correlated with monosomy of chromosome 3 and gain of chromosome 8q. Hence, molecular analysis of UM is useful for diagnosis and prognosis. The aim of this study is to evaluate the use of digital PCR (dPCR) for molecular analysis of UM.
METHODS: A series of 66 UM was analysed with dPCR for three hotspot mutations in GNAQ/GNA11 with mutation specific probes. The status of chromosomes 3 and 8 were analysed with genomic probes. The results of dPCR analysis were cross-validated with Sanger sequencing, SNP array analysis, and karyotyping.
RESULTS: Using dPCR, we were able to reconstitute the molecular profile of 66 enucleated UM. With digital PCR, GNAQ/GNA11 mutations were detected in 60 of the 66 UM. Sanger sequencing revealed three rare variants, and, combined, these assays revealed GNAQ/GNA11 mutations in 95% of UM. Monosomy 3 was present in 43 and chromosome 8 aberrations in 52 of the 66 UM. Survival analysis showed that increasing 8q copy numbers were positively correlated with metastasis risk.
CONCLUSION: Molecular analysis with dPCR is fast and sensitive. Just like the recurrent genomic aberrations of chromosome 3 and 8, hotspot mutations in GNAQ and GNA11 are effectively detected in heterogeneous samples. Increased sensitivity contributes to the number of mutations and chromosomal aberrations detected. Moreover, quantification of copy number with dPCR validated 8q dosage as a sensitive prognostic tool in UM, of which implementation in disease prediction models will further improve prognostication.

Pappa KI, Vlachos GD, Roubelakis M, et al.
Low mutational burden of eight genes involved in the MAPK/ERK, PI3K/AKT, and GNAQ/11 pathways in female genital tract primary melanomas.
Biomed Res Int. 2015; 2015:303791 [PubMed] Free Access to Full Article Related Publications
Mucosal melanomas exhibit discrete genetic features compared to cutaneous melanoma. Limited studies on gynecological melanomas revealed significant heterogeneity and low mutational burden. To gain further insight into their genetics and DNA repair efficiency, we systematically investigated the status of eight genes whose products are critically involved in the MAPK/ERK, PI3K/AKT, and GNAQ/11 pathways, including BRAF, NRAS, HRAS, KRAS, c-KIT, PI3K, GNAQ, and GNA11, in a series of 16 primary gynecological melanomas, covering all anatomical locations, ranging from stages I to III. Analysis either by real-time PCR coupled with fluorescence melting curve analysis or by PCR followed by direct sequencing, along with studies for DNA mismatch repair status using immunohistochemistry, disclosed that 15 out of the 16 cases displayed wild-type genotypes, with a single case of vulvar primary melanoma, harboring the activating mutation BRAF(V600E). Investigations on whether this could reflect partly an efficient mismatch repair (MMR) mechanism were confirmed by normal expression of hMLH1 and hMSH2, suggesting that the lack of mutations could be explained by the operation of alternative pathogenetic mechanisms modulating downstream effectors of the signaling pathways. Our data suggest the presence of additional genetic components and provide the impetus for systematic approaches to reveal these yet unidentified genetic parameters.

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