GNAQ Mutations Research Articles

Next-Generation Sequencing of Uveal Melanoma for Detection of Genetic Alterations Predicting Metastasis.

PurposeTo clinically use the UCSF500, a pancancer, next-generation sequencing assay in uveal melanoma (UM) and to correlate results with gene expression profiling (GEP) and predictive factors for metastasis.MethodsCohort study. Tumor samples of adult UM patients were analyzed with the UCSF500 and GEP. Main outcomes were copy number changes in chromosomes 1, 3, 6, and 8 and mutations in GNAQ, GNA11, SF3B1, EIF1AX, BAP1, SRSF2, U2AF1, and PLCB4. Chromosome 3 loss (a metastasis predictor) was tested for correlation with GEP class, tumor characteristics (largest basal diameter, thickness, ciliary body involvement, and extraocular extension), and histology (presence of epithelioid cells, closed loops, and mitotic count).ResultsThe 62 patients had a mean age of 59 years (range, 24–89 years). Chromosome 3 loss was detected in 30 patients and was associated with larger basal tumor diameter (Wilcoxon rank sum test, P = 0.015), greater thickness (Wilcoxon rank sum test, P = 0.016) and tumor, node, metastasis stage (Fisher test, P = 0.006), epithelioid cytology (Fisher test, P < 0.001), BAP1 mutation (Fisher test, P < 0.001), and chromosome 8q gain (Fisher test, P < 0.001). Class 2 tumors were much more likely to have chromosome 3 loss than class 1 (odds ratio, 121; P < 0.001). Eleven patients developed metastatic UM, of which five died during the study. All metastatic cases had chromosome 3 loss, 8 gain, BAP1 mutation, and class 2 GEP. Five class 1 tumors had chromosome 3 loss.ConclusionsUCSF500 detects chromosomal copy number changes and missense mutations that correlate strongly with metastasis predictors, including GEP.Translational RelevanceNext-generation sequencing of UM should enhance survival prognostication.

29. Clinical use of a rapid and targeted NRAS-BRAF mutation test for melanoma samples; when and if to reflex to next generation sequencing

Melanoma is the fifth most common cancer and understanding the molecular mechanisms behind this type of cancer is key for treatment. Next generation sequencing (NGS) has become a standard for identifying mutations but has high turnaround time (TAT) and cost. The Idylla™ NRAS-BRAF mutation test from Biocartis is a real-time PCR-based assay with a TAT of <24 h that identifies 23 mutations in the NRAS-BRAF genes. However not all clinically significant NRAS or BRAF mutations are covered by Idylla™ and the assay does not identify mutations in KIT, CTNNB1 or GNAQ. To determine if NGS should still be used regardless of Idylla™ result, only following a negative Idylla™ result, or not at all, we did a retrospective study on 310 melanoma specimens sequenced by the Ion AmpliSeq Cancer Hotspot Panel v2 from 2013-2019 at DHMC. A total of 181 melanomas (58.39%) had a mutation in NRAS and/or BRAF that would be identified by Idylla™. Of the 129 cases that would have a negative result by Idylla™, 24 (18.60%) had a reportable mutation in KIT, CTNNB1, NRAS, or BRAF yet only 7/24 could be considered clinically actionable. Seven additional cases had a mutation in NRAS or BRAF that would be identified by Idylla™ and had a reportable KIT or CTNNB1 mutation, however none of these were clinically actionable. In conclusion, the Idylla™ NRAS-BRAF mutation test covers the vast majority of clinically actionable mutations for melanomas and reflexing to NGS only when the Idylla™ results are negative is likely the best approach.

Distinct Genomic Patterns in Pigmented Epithelioid Melanocytoma: A Molecular and Histologic Analysis of 16 Cases.

Pigmented epithelioid melanocytoma (PEM) is considered an intermediate grade melanocytic lesion that is histologically indistinguishable from epithelioid blue nevi associated with Carney complex. PEM are characterized by an intradermal population of heavily pigmented epithelioid-shaped melanocytes along with some spindled and dendritic melanocytes with frequent melanophages. These melanocytic tumors occasionally involve regional lymph nodes but only rarely result in distant metastases. Recent studies have demonstrated a variable but limited number of specific genomic aberrations including protein kinase A regulatory subunit alpha (PRKAR1A), BRAF, GNAQ, and MAP2K1 mutations as well as protein kinase C alpha isoform (PRKCA) fusions. We performed an 8-year retrospective review of our database and identified 16 cases of PEM. Using targeted DNA sequencing and RNA-seq to assess 1714 cancer-related genes, we detected gene fusions involving PRKCA in 31% of cases (5/16) with 5' partners SCARB1(12q24) in 2 cases, CD63 (12q13) in 1 case, ATP2B4 (1q32) in 1 case, and MAP3K3 (17q23) in 1 case. Additional fusions were identified in TPR-NTRK1 (1/16), ALK (1/16), and MYO5A-NTRK3 (1/16). PRKCA fusion lesions tended to occur in younger-aged patients and histologic examination demonstrated sheets of monomorphic epithelioid-shaped melanocytes, moderate to high-grade nuclear atypia, and higher mitotic activity (P=0.037). Our gene panel also identified previously described mutations in PRKAR1A, GNAQ, MAP2K1, BRAF, NF1. To our knowledge, this is the largest and most comprehensive study of PEM integrating molecular data with histologic features that can be utilized in future studies for improved subclassification and prognostication of heavily pigmented melanocytic neoplasms.

Extracutaneous manifestations in phacomatosis cesioflammea and cesiomarmorata: Case series and literature review

Phacomatosis pigmentovascularis (PPV) comprises a family of rare conditions that feature vascular abnormalities and melanocytic lesions that can be solely cutaneous or multisystem in nature. Recently published work has demonstrated that both vascular and melanocytic abnormalities in PPV of the cesioflammea and cesiomarmorata subtypes can result from identical somatic mosaic activating mutations in the genes GNAQ and GNA11. Here, we present three new cases of PPV with features of the cesioflammea and/or cesiomarmorata subtypes and mosaic mutations in GNAQ or GNA11. To better understand the risk of potentially occult complications faced by such patients we additionally reviewed 176 cases published in the literature. We report the frequency of clinical findings, their patterns of co-occurrence as well as published recommendations for surveillance after diagnosis. Features assessed include: capillary malformation; dermal and ocular melanocytosis; glaucoma; limb asymmetry; venous malformations; and central nervous system (CNS) anomalies, such as ventriculomegaly and calcifications. We found that ocular findings are common in patients with phacomatosis cesioflammea and cesiomarmorata. Facial vascular involvement correlates with a higher risk of seizures (p = .0066). Our genetic results confirm the role of mosaic somatic mutations in GNAQ and GNA11 in phacomatosis cesioflammea and cesiomarmorata. Their clinical and molecular findings place these conditions on a clinical spectrum encompassing other GNAQ and GNA11 related disorders and inform recommendations for their management.

Direct targeting of Gαq and Gα11 oncoproteins in cancer cells.

Somatic gain-of-function mutations of GNAQ and GNA11, which encode α subunits of heterotrimeric Gαq/11 proteins, occur in about 85% of cases of uveal melanoma (UM), the most common cancer of the adult eye. Molecular therapies to directly target these oncoproteins are lacking, and current treatment options rely on radiation, surgery, or inhibition of effector molecules downstream of these G proteins. A hallmark feature of oncogenic Gαq/11 proteins is their reduced intrinsic rate of hydrolysis of guanosine triphosphate (GTP), which results in their accumulation in the GTP-bound, active state. Here, we report that the cyclic depsipeptide FR900359 (FR) directly interacted with GTPase-deficient Gαq/11 proteins and preferentially inhibited mitogenic ERK signaling rather than canonical phospholipase Cβ (PLCβ) signaling driven by these oncogenes. Thereby, FR suppressed the proliferation of melanoma cells in culture and inhibited the growth of Gαq-driven UM mouse xenografts in vivo. In contrast, FR did not affect tumor growth when xenografts carried mutated B-RafV600E as the oncogenic driver. Because FR enabled suppression of malignant traits in cancer cells that are driven by activating mutations at codon 209 in Gαq/11 proteins, we envision that similar approaches could be taken to blunt the signaling of non-Gαq/11 G proteins.

Pathologic Features of Tumor Activity and Stability in Uveal Melanoma Specimens after Fractionated CyberKnife Radiosurgery.

To evaluate uveal melanoma cell activity and pathologic features after stereotactic CyberKnife radiosurgery in specimens from five patients. Specimens from five patients treated by CyberKnife radiosurgery in three fractions were included in this study. Because of persistent retinal detachment in 3 patients, tumour endoresection was performed at four, seven and ten month after CyberKnife radiosurgery. At nine and twelve months after treatment, enucleation of the eye globe was performed in 2 patients because of secondary tumour bleeding and missing regression. After histomorphological analysis and determination of Ki67-proliferation index, DNA cytophotometry, fluorescence in-situ hybridization evaluation for chromosome 3 loss, GNA11and GNAQ mutation analysis were performed. Four of the five tumours included in this study showed variable radiation-induced morphologic changes in the form of enlargement of cells and nuclei, cytoplasmic vacuolisation and nuclear fragmentation. The DNA content of a large fraction of tumour cells was hypoploid. On the other hand, single strikingly hyperchromatic melanoma cells showed marked aneuploidy. The proliferation fraction in the three endoresected tumours was very low (<1%), but it was elevated in the enucleation cases. Monosomy 3 was detected in two of the endoresection cases, but none of the enucleation cases. None of the patients experienced a local tumour recurrence, but two of the patients developed liver metastasis. Many melanoma cells seemed to be vital within the first 6months after CyberKnife radiosurgery, but obvious radiation-induced morphologic changes, including tumour necrosis, hypoploid DNA content plus low Ki-67 index could indicate sublethal cell damage.

Cherry Angiomas—Further Expanding the Phenotype With Somatic GNAQ and GNA11 Mutations

Cherry Angiomas—Further Expanding the Phenotype With Somatic GNAQ and GNA11 Mutations

Genetic Profiling of Primary Orbital Melanoma: An Analysis of 6 Cases with Clinicopathologic Correlation

To analyze the genetic profile of 6 cases of primary orbital melanoma with clinicopathologic correlation. Retrospective noninterventional study to analyze the genetic profile of 6 cases of primary orbital melanoma and to correlate the genetic findings with prognosis and clinicopathologic features. Inclusion criteria were patients with primary orbital melanoma with no evidence of primary eyelid skin, conjunctival, uveal, or remote melanoma at extraocular sites. The study involved 6 primary orbital melanomas from 6 patients. Four patients were exenterated and 2 had incisional biopsies performed. Clinical notes and radiologic records were assessed to ascertain clinical tumor behavior. Sections were stained with hematoxylin-eosin and exposed to immunohistochemistry for S100, MelA, HMB45, Sox10, and BAP1. Melanoma DNA was exposed to array comparative genomic hybridization to assess gross chromosomal copy number changes. Point mutation assessment and Sanger sequencing were performed for GNAQ, GNA11, BRAF, NRAS, pTERT, SF3B1, and EIF1AX. These were the presence of gross chromosomal copy number changes and the presence of mutations in GNAQ, GNA11, BRAF, NRAS, pTERT, SF3B1, and EIF1AX; the presence of metastases and time period between diagnosis and death from melanoma; and correlation between the tumor genetic profile and the clinical behavior of the tumor. One of the 6 cases was clinically associated with oculodermal melanocytosis. Of the 6 patients, 3 died of melanoma metastases and 1 of unrelated causes; 2 remain alive at last review. Three of the 6 cases were histologically associated with a benign precursor lesion. All melanomas expressed S100, MelA, HMB45, and Sox10. One patient showed loss of BAP1 nuclear staining. The most frequent chromosomal gains across the 6 cases, in order of frequency, were 6p, 8q, 17q, 6q, and 20p. The most frequently lost regions were 1p, 9p, 16q, and 17p. One patient showed monsomy 3 and gain of 8q (and showed the BAP1 loss). Mutations were found in GNAQ (1 case), GNA11 (1 case), SF3B1 (2 cases), NRAS (2 cases), and pTERT (2 cases). The data point to 2 genetic groups for primary orbital conjunctiva melanoma-like and a uveal melanoma-like group. A larger study would help confirm this suggestion.

Physical and Family History Variables Associated With Neurological and Cognitive Development in Sturge-Weber Syndrome

BackgroundSturge-Weber syndrome (SWS) is caused by a somatic mutation in GNAQ leading to capillary venous malformations in the brain presenting with various neurological, ophthalmic, and cognitive symptoms of variable severity. This clinical variability makes accurate prognosis difficult. We hypothesized that the greater extent of physical factors (extent of skin, eye, and brain involvement), presence of possible genetic factors (gender and family history), and age of seizure onset may be associated with greater symptom severity and need for surgery in patients with SWS. MethodsThe questionnaire was collected from 277 participants (age: two months to 66 years) with SWS brain involvement at seven US sites. ResultsBilateral brain involvement was associated with both learning disorder and intellectual disability, whereas port-wine birthmark extent was associated with epilepsy and an increased likelihood of glaucoma surgery. Subjects with family history of vascular birthmarks were also more likely to report symptomatic strokes, and family history of seizures was associated with earlier seizure onset. Learning disorder, intellectual disability, strokelike episodes, symptomatic stroke, hemiparesis, visual field deficit, and brain surgery were all significantly associated with earlier onset of seizures. ConclusionThe extent of brain and skin involvement in SWS, as well as the age of seizure onset, affect prognosis. Other genetic factors, particularly variants involved in vascular development and epilepsy, may also contribute to neurological prognosis, and further study is needed.

GNAQ Mutations in Diffuse and Solitary Choroidal Hemangiomas

GNAQ mutations have been identified in port wine stains (both syndromic and nonsyndromic) and melanocytic ocular neoplasms. This study investigates the presence of GNAQ mutations in diffuse (those associated with Sturge-Weber syndrome [SWS]) and solitary choroidal hemangiomas. Tissue from 11 patients with the following diagnoses: port wine stain (n= 3), diffuse choroidal hemangioma (n= 1), solitary choroidal hemangioma (n= 6), and choroidal nevus (n= 1). Ten specimens were interrogated with Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets, a hybridization capture-based next-generation sequencing assay for targeted deep sequencing of all exons and selected introns of 468 key cancer genes in formalin-fixed, paraffin-embedded tumors. Digital polymerase chain reaction was used to detect GNAQ Q209 mutation in 1 specimen. Detection of GNAQ codon-specific mutation. Activating somatic GNAQ mutations (c.547C > T; p.Arg183Cys) were found in 100% (3 of 3) of the port wine stain and in the diffuse choroidal hemangioma. Somatic GNAQ mutations (c.626A > T; p.Gln209Leu) were found in 100% (6 of 6) of the solitary choroidal hemangiomas and (c.626A > C; p.Gln209Pro) in the choroidal nevus. GNAQ mutations occur in both diffuse and solitary hemangiomas, although at distinct codons. An R183 codon is mutant in diffuse choroidal hemangiomas, consistent with other Sturge-Weber vascular malformations. By contrast, solitary choroidal hemangiomas have mutations in the Q209 codon, similar to other intraocular melanocytic neoplasms.

Detection of mutations in SF3B1, EIF1AX and GNAQ in primary orbital melanoma by candidate gene analysis

BackgroundOcular melanoma is a rare but often deadly malignancy that arises in the uvea (commonest primary site), conjunctiva or the orbit. Primary orbital melanoma (POM) is exceedingly rare, with approximately 60 cases reported to date. Despite recent advances in our understanding of the genetics of primary uveal and conjunctival melanomas, this information is lacking for POM.MethodsDNA was extracted from 12 POM tissues, with matched germline DNA (where available). MLPA was conducted to detect chromosomal alterations and Sanger sequencing used to identify point mutations in candidate melanoma driver genes (BRAF, NRAS, KRAS, GNA11, GNAQ), and other genes implicated in melanoma prognosis (EIF1AX, SF3B1). Immunohistochemistry was performed to analyse BAP1 nuclear expression.ResultsMLPA detected copy number alterations in chromosomes 1p, 3, 6 and 8. Sequencing of melanoma driver genes revealed GNAQ (p.Q209L) mutations in two samples; although it is possible that these samples represent extraocular spread of an occult uveal melanoma. A recurrent mutation in SF3B1 (p.R625H) was observed in indolent, but not aggressive, tumours; a mutation in EIF1AX (p.N4S) was detected in one patient with non-aggressive disease.ConclusionsEIF1AX and SF3B1 mutations appear have a role in determining the clinical course of POM and detection of these changes could have clinical significance. Further in depth analysis of this rare group using differing ‘omic technologies will provide novel insights into tumour pathogenesis.

Atypical activation of the G protein Gαq by the oncogenic mutation Q209P

The causative role of G protein-coupled receptor (GPCR) pathway mutations in uveal melanoma (UM) has been well-established. Nearly all UMs bear an activating mutation in a GPCR pathway mediated by G proteins of the Gq/11 family, driving tumor initiation and possibly metastatic progression. Thus, targeting this pathway holds therapeutic promise for managing UM. However, direct targeting of oncogenic Gαq/11 mutants, present in ∼90% of UMs, is complicated by the belief that these mutants structurally resemble active Gαq/11 WT. This notion is solidly founded on previous studies characterizing Gα mutants in which a conserved catalytic glutamine (Gln-209 in Gαq) is replaced by leucine, which leads to GTPase function deficiency and constitutive activation. Whereas Q209L accounts for approximately half of GNAQ mutations in UM, Q209P is as frequent as Q209L and also promotes oncogenesis, but has not been characterized at the molecular level. Here, we characterized the biochemical and signaling properties of Gαq Q209P and found that it is also GTPase-deficient and activates downstream signaling as efficiently as Gαq Q209L. However, Gαq Q209P had distinct molecular and functional features, including in the switch II region of Gαq Q209P, which adopted a conformation different from that of Gαq Q209L or active WT Gαq, resulting in altered binding to effectors, Gβγ, and regulators of G-protein signaling (RGS) proteins. Our findings reveal that the molecular properties of Gαq Q209P are fundamentally different from those in other active Gαq proteins and could be leveraged as a specific vulnerability for the ∼20% of UMs bearing this mutation.

Molecular and genetic diversity in melanoma of eye

Background. Ocular melanoma is the most common cancer of adult eye and is represented by two main subtypes of uveal (UM) and conjunctival (CM) melanoma with distinct clinical (frequency, localization, histology) and genomic features. The objective is to compare molecular and genetic characteristics of tumors in patients with melanoma of the eye. Materials and methods. In this study molecular profiling of 78 tumors including 73 UM (choroidea, ciliar body and iris) and 5 СM, was evaluated. DNA was isolated from tumor cells collected by macrodissection of FEPE sections of tumor biopsies using proteinase K. The following genes were studied by Sanger sequencing: GNAQ, GNA11, KIT, BRAF, NRAS. Results. Mutations in GNAQ and GNA11 were found in 81 % (59/73) of UM, in 42 % (31/73) and 38 % (28/73) of cases correspondently. GNAQ mutations were more frequent in primary UM (63 %), while GNA11 mutations dominated in metastatic UM (42 %). There was а correlation between frequency of GNAQ/GNA11 mutations and histologic type of UM. GNAQ mutations were identified in 55 % of spindle cell UM, while GNA11 mutations were more frequent in epithelioid cell UM (42 %). There were no differences in frequency of GNAQ/GNA11 mutations in UM of patients of different age (younger and elder 50 years). There was no statistically difference in UM patient outcome with GNAQ or GNA11 mutations. We also detected 3 UM with KIT mutations and 2 UM with BRAF mutations. There was no big difference in frequency of «driver mutations» in UM of choroidea, ciliar body and iris. Molecular profiling of conjunctival melanoma (CM) resembles that of cutaneous melanoma of skin: in 3 (60 %) CM BRAF V600E was identified and in 1 (20 %) – NRAS Q61K. Conclusion. Genetic analysis reveals wide diversity of melanoma of eye and is important for it characterization and treatment.

GNAQ mutation in port-wine macrocheilia

Capillary malformations (CMs), also called port‐wine stains, are a type of birthmark which affect about 3 to 5 out of every 1000 newborn babies. Port‐wine macrocheilia (PWM) are CMs that also cause the lips to enlarge. It is known that port wine stains are caused by a mutation in a protein called GNAQ and this study by researchers in P.R. China aimed to figure out how often this mutation occurs in different tissues of PWM, such as skin, mucosa (e.g. the tissue inside the mouth and nose), gland, and muscle. The authors found that the mutation, called GNAQ(R183Q) mutation, was not present in gland samples, but it was detected in 90%, 95% and 95% of the skin, mucosa and muscle samples, respectively. The study also found a positive correlation between the GNAQ mutation frequency and clinical characteristics, meaning that the mutation was linked to symptoms, especially in mucosa. Thus, the authors hypothesize that GNAQ mutation in mucosa of the lips, with or without underlying port wine stain in the skin, may be used as a predictor for early‐stage PWM. The authors suggest that performing a biopsy of mucosa (testing a small skin sample) if doctors think the patient might have underlying port wine stain, could help detect PWM earlier and allow for earlier treatment. Biopsies are practical, convenient, heal rapidly and don't cause scarring.

Frequent GNAQ and GNA14 Mutations in Hepatic Small Vessel Neoplasm.

Hepatic small vessel neoplasm (HSVN) is a recently described infiltrative vascular neoplasm of the liver, composed of small vessels. Although the infiltrative nature can mimic angiosarcoma, HSVN are thought to be benign or low-grade neoplasms because they lack cytologic atypia and increased proliferation. To characterize the molecular pathogenesis of HSVN, we performed both targeted panel sequencing and exome sequencing on 18 benign or low-grade vascular neoplasms in the liver including 8 HSVN, 6 classic cavernous hemangioma (CH), and 4 variant lesions (VL) with overlapping features between HSVN and CH. All 18 lesions had simple genomes without copy number alterations. In total, 75% (6/8) of HSVN demonstrated known activating hotspot mutations in GNAQ (2/8, p.Q209H) or GNA14 (4/8, p.Q205L), and the remaining 2 had the same missense mutation in GNAQ, p.G48L, which has not been previously described. 25% (1/4) of VL had a hotspot GNAQ p.Q209H mutation and another VL had a GNAQ p.G48L mutation. Known pathogenic mutations were not identified in any of the 6 CH. These data suggest that HSVN share a similar molecular biology to several other vascular lesions (congenital hemangioma, tufted angioma, anastomosing hemangioma, lobular capillary hemangioma, and kaposiform hemangioendothelioma) recently reported to have GNAQ, GNA11, or GNA14 mutations.

LB1539 Genotype-first phenotyping of 32 patients with post-zygotic GNAQ or GNA11 mutations

LB1539 Genotype-first phenotyping of 32 patients with post-zygotic GNAQ or GNA11 mutations

Somatic GNAQ mutation in different structures of port-wine macrocheilia.

Port-wine macrocheilia (PWM) involves a congenital, progressive capillary malformation that results in soft-tissue hypertrophy in the lips. Its aetiology has not yet been fully elucidated. To investigate frequencies of GNAQ mutation in different tissues from patients with PWM, including skin, mucosa, gland and muscle, using samples obtained during cheiloplasty. Targeted next-generation sequencing of GNAQ was designed and performed to assess DNA extracted from 80 different affected tissues from 20 patients with PWM. The GNAQ R183Q mutation was not detected in gland samples but was found in 90%, 95% and 95% of the skin, mucosal and muscle samples, respectively. The lowest levels of mutations were found in the glands (P < 0·001 vs. skin, mucosa and muscle), and levels were second lowest in the skin (P = 0·023 vs. mucosa; P = 0·012 vs. muscle). The mutation frequencies in mucosa and muscle were the highest and showed no statistically significant difference (P = 0·92). In patients with PWM, GNAQ was mutated in all tissues except for glands. PWM is congenital, and all tissue layers exhibit primary hypertrophy rather than acquired or partially related hypertrophy. Given the advantages of mucosal biopsy, including practicality, lack of scarring and rapid healing, GNAQ mutation in the lip mucosa may be a useful predictor for early-stage PWM in patients with port-wine stains affecting the lips.

Chromosomal rearrangements in uveal melanoma: Chromothripsis.

Uveal melanoma (UM) is the most common primary intraocular malignancy in the Western world. Recurrent mutations in GNAQ, GNA11, CYSLTR2, PLCB4, BAP1, EIF1AX, and SF3B1 are described as well as non‐random chromosomal aberrations. Chromothripsis is a rare event in which chromosomes are shattered and rearranged and has been reported in a variety of cancers including UM. SNP arrays of 249 UM from patients who underwent enucleation, biopsy or endoresection were reviewed for the presence of chromothripsis. Chromothripsis was defined as ten or more breakpoints per chromosome involved. Genetic analysis of GNAQ, GNA11, BAP1, SF3B1, and EIF1AX was conducted using Sanger and next‐generation sequencing. In addition, immunohistochemistry for BAP1 was performed. Chromothripsis was detected in 7 out of 249 tumors and the affected chromosomes were chromosomes 3, 5, 6, 8, 12, and 13. The mean total of fragments per chromosome was 39.8 (range 12‐116). In 1 UM, chromothripsis was present in 2 different chromosomes. GNAQ, GNA11 or CYSLTR2 mutations were present in 6 of these tumors and 5 tumors harbored a BAP1 mutation and/or lacked BAP1 protein expression by immunohistochemistry. Four of these tumors metastasized and for the fifth only short follow‐up data are available. One of these metastatic tumors harbored an SF3B1 mutation. No EIF1AX mutations were detected in any of the tumors. To conclude, chromothripsis is a rare event in UM, occurring in 2.8% of samples and without significant association with mutations in any of the common UM driver genes.

An insight into the molecular genetics of a uveal melanoma patient cohort

Uveal melanoma (UM) is a highly aggressive malignancy and presents a clinically significant unmet need in cancer therapeutics. The aim of this study was to identify previously unreported mutations in UM among an Irish cohort of patients which may have potential clinical relevance. DNA was extracted from 36 intraocular melanoma patient samples and 4 metastatic melanoma samples among the patient cohort by microdissection from formalin-fixed paraffin embedded tissue blocks and underwent genotyping to test for known single nucleotide polymorphisms in 42 cancer associated genes. These mutations were analysed using a custom-designed sequenom panel. Using high-throughput genotyping, mutually exclusive GNAQ and GNA11 mutations were detected in 31 of 34 UM patients together with a number of non-synonymous changes in established cancer driver genes, PHLPP2, MET, PIK3R1 and IDH-1, variants which have not been previously associated with UM. Given the lack of knowledge regarding the clinical relevance of the variants identified in this UM cohort and their likely pathogenic nature in other cancers, further studies of the functional impact of these variant mutations are warranted to establish possible previously, undescribed roles in UM pathogenesis, which may provide additional targets for future therapies.

Abstract 968: Targeting FAK inhibits YAP-dependent tumor growth in uveal melanoma

Abstract Activating mutations in GNAQ and GNA11 (known as GNAQ oncogenes), which encode constitutively active Gαq proteins, occur in ~90% of uveal melanoma (UM) and 4% of skin cutaneous melanoma (SKCM) respectively. UM is the most common primary cancer of the eye in adults, diagnosed in about 2,500 adults in the US every year. Approximately 50% of UM patients develop liver metastasis within 5-10 years after diagnosis, independently of the successful treatment of the primary lesions. There are effective therapeutic strategies for primary UM lesions, but UM metastatic disease is refractory to current chemotherapies and immune checkpoint inhibitors, and most patients with UM metastasis die within a year. The MEK inhibitor selumetinib has been recently approved for UM treatment, but MEK inhibition has nearly no impact on UM patient overall survival. To date, there are no effective treatment options for metastatic UM. We used bioinformatics approaches to identify systems vulnerabilities that can be exploited for UM treatment. Using the TCGA UM dataset (N=80) and SKCM samples that do not harbor Gαq genomic alterations (N=209) as control, (i) we first identified genes that are highly overexpressed in UM. We validated this approach by confirming that the genes over- and under-expressed in UM and Gαq-altered SKCM are highly overlapping (hyper-geometric p&amp;lt;1E-198 and p&amp;lt;1E-232 respectively). ii) We then filtered the genes for those whose inactivation leads to better patient survival in UM based on TCGA survival data. (iii) We finally used large datasets of gene essentiality and drug response screens in cancer cells to identify genes that are predicted to reduce cell viability when targeted in Gαq-expressing tumors. By filtering these genes for those that can be targeted by approved and experimental drugs (N=756), we identified 7 candidate druggable genes. Among them, the top was PTK2, which encodes a non- receptor tyrosine kinase known as FAK (focal adhesion kinase). By dissecting the Gαq signaling pathway, we found that Gαq actives FAK (p379-FAK) through a Trio-RhoA signaling pathway, independent of PLC-β regulated second messenger systems. RNA-seq of UM cells treated with a FAK inhibitor (FAKi, VS-4718) revealed that YAP gene-expression signatures were highly sensitive to FAKi. Of interest, YAP is a key regulator of cancer growth, and we have shown that YAP is highly activated by Gαq in UM, contributing to tumor growth (Cancer Cell. 2014). We found FAK regulates YAP activation by Gαq through a mechanism that involves YAP tyrosine phosphorylation on Y357. Interestingly, CRISPR-Cas9 KO of FAK and clinically relevant FAKi showed strong inhibition of UM growth in vitro and in vivo, concomitant with repression of YAP-regulated gene programs. Overall, our computational biology approach revealed that FAK may represent a novel precision therapeutic target human diseases initiated by aberrant Gαq signaling, including UM, the first identified Gαq-driven human malignancy. Citation Format: Xiaodong Feng, Damiano Rigiracciolo, Joo-Sang Lee, Huwate Yeerna, Nadia Arang, Simone Lubrano, David D. Schlaepfer, Pablo Tamayo, Eytan Ruppin, J. Silvio Gutkind. Targeting FAK inhibits YAP-dependent tumor growth in uveal melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 968.