A somatic GNA11 mutation is associated with extremity capillary malformation and overgrowth

Human iPSC and CRISPR targeted gene knock-in strategy for studying the somatic TIE2L914F mutation in endothelial cells

Induced pluripotent stem cell (iPSC) derived endothelial cells (iECs) have emerged as a promising tool for studying vascular biology and providing a platform for modelling various vascular diseases, including those with genetic origins. Currently, primary ECs are the main source for disease modelling in this field. However, they are difficult to edit and have a limited lifespan. To study the effects of targeted mutations on an endogenous level, we generated and characterized an iPSC derived model for venous malformations (VMs). CRISPR-Cas9 technology was used to generate a novel human iPSC line with an amino acid substitution L914F in the TIE2 receptor, known to cause VMs. This enabled us to study the differential effects of VM causative mutations in iECs in multiple in vitro models and assess their ability to form vessels in vivo. The analysis of TIE2 expression levels in TIE2L914F iECs showed a significantly lower expression of TIE2 on mRNA and protein level, which has not been observed before due to a lack of models with endogenous edited TIE2L914F and sparse patient data. Interestingly, the TIE2 pathway was still significantly upregulated and TIE2 showed high levels of phosphorylation. TIE2L914F iECs exhibited dysregulated angiogenesis markers and upregulated migration capability, while proliferation was not affected. Under shear stress TIE2L914F iECs showed reduced alignment in the flow direction and a larger cell area than TIE2WT iECs. In summary, we developed a novel TIE2L914F iPSC-derived iEC model and characterized it in multiple in vitro models. The model can be used in future work for drug screening for novel treatments for VMs.

Molecular Basis and Diagnostic Approach to Isolated and Syndromic Lateralized Overgrowth in Childhood

OBJECTIVE

To demonstrate a high-yield molecular diagnostic workflow for lateralized overgrowth (LO), a congenital condition with abnormal enlargement of body parts, and to classify it by molecular genetics.

STUDY DESIGN

We categorized 186 retrospective cases of LO diagnosed between 2003 and 2023 into suspected Beckwith-Wiedemann spectrum, PIK3CA-related overgrowth spectrum (PROS), vascular overgrowth, or isolated LO, based on initial clinical assessments, to determine the appropriate first-tier molecular tests and tissue for analysis. Patients underwent testing for 11p15 epigenetic abnormalities or somatic variants in genes related to PI3K/AKT/mTOR, vascular proliferation, and RAS-MAPK cascades using blood or skin DNA. For cases with negative initial tests, a sequential cascade molecular approach was employed to improve diagnostic yield.

RESULTS

This approach led to a molecular diagnosis in 54% of cases, 89% of cases consistent with initial clinical suspicions, and 11% reclassified. Beckwith-Wiedemann spectrum was the most common cause, with 43% of cases exhibiting 11p15 abnormalities. PIK3CA-related overgrowth spectrum had the highest confirmation rate, with 74% of clinically diagnosed patients showing a PIK3CA variant. Vascular overgrowth demonstrated significant clinical overlap with other syndromes. A molecular diagnosis of isolated LO proved challenging, with only 21% of cases classifiable into a specific condition.

CONCLUSIONS

LO is underdiagnosed from a molecular viewpoint and to date has had no diagnostic guidelines, which is crucial for addressing potential cancer predisposition, enabling precision medicine treatments, and guiding management. This study sheds light on the molecular etiology of LO, highlighting the importance of a tailored diagnostic approach and of selecting appropriate testing to achieve the highest diagnostic yield.

Congenital Vascular and Lymphatic Diseases

Over the past several centuries, the integration of contemporary medical techniques and innovative technologies, like genetic sequencing, have played a pivotal role in enhancing our comprehension of congenital vascular and lymphatic disorders. Nonetheless, the uncommon and complex characteristics of these disorders, especially considering their formation during the intrauterine stage, present significant obstacles in diagnosis and treatment. Here, we review the intricacies of these congenital abnormalities, offering an in-depth examination of key diagnostic approaches, genetic factors, and therapeutic methods.

Similarities and differences between brain and skin GNAQ p.R183Q driven capillary malformations

Capillary malformations (CM) are congenital vascular irregularities of capillary and venous blood vessels that appear in the skin, leptomeninges of the brain, and the choroid of the eye in the disorder known as Sturge Weber Syndrome (SWS). More common are non-syndromic CM found only in the skin, without brain or ocular involvement. A somatic activating mutation in GNAQ (p.R183Q) is found in ~90% of syndromic and non-syndromic CM specimens and is present in CD31pos endothelial cells isolated from brain and skin CM specimens. Endothelial expression of the GNAQ p.R183Q variant is sufficient to form CM-like vessels in mice. Given the distinct features and functions of blood vessels in the brain versus the skin, we examined the features of CM vessels in both tissues to gain insights into the pathogenesis of CM. Herein, we present morphologic characteristics of CM observed in specimen from brain and skin. The GNAQ p.R183Q variant allelic frequency in each specimen was determined by droplet digital PCR. Sections were stained for endothelial cells, tight junctions, mural cells, and macrophages to assess the endothelium as well as perivascular constituents. CM blood vessels in brain and skin were enlarged, exhibited fibrin leakage and reduced zona occludin-1, and were surrounded by MRC1pos/LYVE1pos macrophages. In contrast, the CMs from brain and skin differ in endothelial sprouting activity and localization of mural cells. These characteristics might be helpful in the development of targeted and/or tissue specific therapies to prevent or reverse non-syndromic and syndromic CM.

Characterization of Patient-Derived GNAQ Mutated Endothelial Cells from Capillary Malformations

Capillary malformations (CM) (port-wine stains) are congenital skin lesions that are characterized by dilated capillaries and postcapillary venules. CMs are caused by altered functioning of the vascular endothelium. Somatic genetic mutations have predominantly been identified in the endothelial cells of CMs, providing an opportunity for the development of targeted therapies. However, there is currently limited in-depth mechanistic insight into the pathophysiology and a lack of preclinical research approaches. In a monocenter exploratory study of 17 adult patients with CMs, we found somatic sequence variants in the GNAQ (p.R183Q, p.R183G, or p.Q209R) or GNA11 (p.R183C) genes. We applied an endothelial-selective cell isolation protocol to culture primary endothelial cells from skin biopsies from these patients. We successfully expanded patient-derived cells in culture in 3 of the 17 cases while maintaining endothelial specificity as demonstrated by vascular endothelial-cadherin immunostainings. In addition, we tested the angiogenic capacity of endothelial cells from a patient with a GNAQ (p.R183G) sequence substitution. These proof-of-principle results reveal that primary cells isolated from CMs may represent a functional research model to investigate the role of endothelial somatic mutations in the etiology of CMs, but improved isolation and culture methodologies are urgently needed to advance the field.

Capillary malformations

Capillary malformation (CM), or port wine birthmark, is a cutaneous congenital vascular anomaly that occurs in 0.1%-2% of newborns. Patients with a CM localized on the forehead have an increased risk of developing a neurocutaneous disorder called encephalotrigeminal angiomatosis or Sturge-Weber syndrome (SWS), with complications including seizure, developmental delay, glaucoma, and vision loss. In 2013, a groundbreaking study revealed causative activating somatic mutations in the gene (GNAQ) encoding guanine nucleotide-binding protein Q subunit α (Gαq) in CM and SWS patient tissues. In this Review, we discuss the disease phenotype, the causative GNAQ mutations, and their cellular origin. We also present the endothelial Gαq-related signaling pathways, the current animal models to study CM and its complications, and future options for therapeutic treatment. Further work remains to fully elucidate the cellular and molecular mechanisms underlying the formation and maintenance of the abnormal vessels.

Secondary Syphilis Presents as Palmoplantar Hyperpigmented Maculopapules: A Case Report

Syphilis is a worldwide chronic systemic sexually transmitted infection caused by the spirochete bacterium Treponema pallidum. Here, we report a 28-year-old homosexual male who presented to the dermatology clinic with a six-month history of asymptomatic persistent skin lesions. A review of systems revealed unintentional weight loss of about 40 kg within one year. Skin examination revealed multiple scaly and non-scaly hyperpigmented macules and patches on the palms and soles. Hair, nail, and mucus membrane examinations were normal. There was no lymphadenopathy. A skin biopsy revealed psoriasiform acanthosis, lichenoid infiltrates with moderately dense mononuclear lymphohistiocytic cells, few plasma cells, and eosinophils. Laboratory investigations revealed positive rapid plasma reagin (RPR) with a titer of 1:128. Treponema pallidum hemagglutination test (TPHA) was positive. The HIV test by western blot was positive. Based on the above clinicopathological and laboratory findings, a diagnosis of secondary syphilis was made in this patient, who also tested positive for HIV. He was given a single dose of penicillin G benzathine (2.4 units) intramuscularly. He was also started on Dolutegravir 50 mg tablet once daily and Tenofovir alafenamide fumarate + Emtricitabine tablet once daily. Three months after penicillin G benzathine treatment, the RPR test turned negative, and the skin lesions disappeared.

MRC1 and LYVE1 expressing macrophages in vascular beds of GNAQ p.R183Q driven capillary malformations in Sturge Weber syndrome

Sturge-Weber syndrome (SWS), a neurocutaneous disorder, is characterized by capillary malformations (CM) in the skin, brain, and eyes. Patients may suffer from seizures, strokes, and glaucoma, and only symptomatic treatment is available. CM are comprised of enlarged vessels with endothelial cells (ECs) and disorganized mural cells. Our recent finding indicated that the R183Q mutation in ECs leads to heightened signaling through phospholipase Cβ3 and protein kinase C, leading to increased angiopoietin-2 (ANGPT2). Furthermore, knockdown of ANGPT2, a crucial mediator of pro-angiogenic signaling, inflammation, and vascular remodeling, in EC-R183Q rescued the enlarged vessel phenotype in vivo. This prompted us to look closer at the microenvironment in CM-affected vascular beds. We analyzed multiple brain histological sections from patients with GNAQ-R183Q CM and found enlarged vessels devoid of mural cells along with increased macrophage-like cells co-expressing MRC1 (CD206, a mannose receptor), CD163 (a scavenger receptor and marker of the monocyte/macrophage lineage), CD68 (a pan macrophage marker), and LYVE1 (a lymphatic marker expressed by some macrophages). These macrophages were not found in non-SWS control brain sections. To investigate the mechanism of increased macrophages in the perivascular environment, we examined THP1 (monocytic/macrophage cell line) cell adhesion to EC-R183Q versus EC-WT under static and laminar flow conditions. First, we observed increased THP1 cell adhesion to EC-R183Q compared to EC-WT under static conditions. Next, using live cell imaging, we found THP1 cell adhesion to EC-R183Q was dramatically increased under laminar flow conditions and could be inhibited by anti-ICAM1. ICAM1, an endothelial cell adhesion molecule required for leukocyte adhesion, was strongly expressed in the endothelium in SWS brain histological sections, suggesting a mechanism for recruitment of macrophages. In conclusion, our findings demonstrate that macrophages are an important component of the perivascular environment in CM suggesting they may contribute to the CM formation and SWS disease progression.

Updates in Genetic Testing for Head and Neck Vascular Anomalies

Vascular anomalies include benign or malignant tumors or benign malformations of the arteries, veins, capillaries, or lymphatic vasculature. The genetic etiology of the lesion is essential to define the lesion and can help navigate choice of therapy. . In the United States, about 1.2% of the population has a vascular anomaly, which may be underestimating the true prevalence as genetic testing for these conditions continues to evolve.

A case report and literature review on reactive cutaneous capillary endothelial proliferation induced by camrelizumab in a nasopharyngeal carcinoma patient

Camrelizumab, a monoclonal antibody, blocks programmed cell death protein-1 from binding to T cells and programmed cell death ligand 1 on tumor cells, thereby ensuring sustained T cell activation and blocking immune escape of various types of cancer, including nasopharyngeal carcinoma. Reactive cutaneous capillary endothelial hyperplasia (RCCEP) is the most common immune-related adverse event in patients treated with camrelizumab. We report a case nasopharyngeal carcinoma in a patient with camrelizumab-induced RCCEP. A 68-year-old man diagnosed with nasopharyngeal carcinoma developed RCCEP at multiple locations after 3 months of camrelizumab treatment. RCCEP of the right lower eyelid affected closure of the right eye. In this report, we also reviewed previous literature on camrelizumab-induced RCCEP. In summary, the mechanism underlying camrelizumab-induced RCCEP remains unclear. RCCEP typically gradually subsides after discontinuing camrelizumab treatment. Larger nodules can be treated with lasers, ligation, or surgery. Although surgical excision is effective, RCCEP may recur in patients undergoing camrelizumab treatment. RCCEP management may not be required in the absence of adverse effects on the patient's daily life.

Targeted next-generation sequencing for detection of PIK3CA mutations in archival tissues from patients with Klippel-Trenaunay syndrome in an Asian population : List the full names and institutional addresses for all authors

BACKGROUND

Klippel-Trenaunay syndrome (KTS) is a rare slow-flow combined vascular malformation with limb hypertrophy. KTS is thought to lie on the PIK3CA-related overgrowth spectrum, but reports are limited. PIK3CA encodes p110α, a catalytic subunit of phosphatidylinositol 3-kinase (PI3K) that plays an essential role in the PI3K/AKT/mammalian target of rapamycin (mTOR) signaling pathway. We aimed to demonstrate the clinical utility of targeted next-generation sequencing (NGS) in identifying PIK3CA mosaicism in archival formalin-fixed paraffin-embedded (FFPE) tissues from patients with KTS.

RESULTS

Participants were 9 female and 5 male patients with KTS diagnosed as capillaro-venous malformation (CVM) or capillaro-lymphatico-venous malformation (CLVM). Median age at resection was 14 years (range, 5-57 years). Median archival period before DNA extraction from FFPE tissues was 5.4 years (range, 3-7 years). NGS-based sequencing of PIK3CA achieved an amplicon mean coverage of 119,000x. PIK3CA missense mutations were found in 12 of 14 patients (85.7%; 6/8 CVM and 6/6 CLVM), with 8 patients showing the hotspot variants E542K, E545K, H1047R, and H1047L. The non-hotspot PIK3CA variants C420R, Q546K, and Q546R were identified in 4 patients. Overall, the mean variant allele frequency for identified PIK3CA variants was 6.9% (range, 1.6-17.4%). All patients with geographic capillary malformation, histopathological lymphatic malformation or macrodactyly of the foot had PIK3CA variants. No genotype-phenotype association between hotspot and non-hotspot PIK3CA variants was found. Histologically, the vessels and adipose tissues of the lesions showed phosphorylation of the proteins in the PI3K/AKT/mTOR signaling pathway, including p-AKT, p-mTOR, and p-4EBP1.

CONCLUSIONS

The PI3K/AKT/mTOR pathway in mesenchymal tissues was activated in patients with KTS. Amplicon-based targeted NGS could identify low-level mosaicism from low-input DNA extracted from FFPE tissues, potentially providing a diagnostic option for personalized medicine with inhibitors of the PI3K/AKT/mTOR signaling pathway.

Somatic mutation spectrum of a Chinese cohort of pediatrics with vascular malformations

BACKGROUND

Somatic mutations of cancer driver genes are found to be responsible for vascular malformations with clinical manifestations ranging from cutaneous birthmarks to life-threatening systemic anomalies. Till now, only a limited number of cases and mutations were reported in Chinese population. The purpose of this study was to describe the somatic mutation spectrum of a cohort of Chinese pediatrics with vascular malformations.

METHODS

Pediatrics diagnosed with various vascular malformations were collected between May 2019 and October 2020 from Beijing Children's Hospital. Genomic DNA of skin lesion of each patient was extracted and sequenced by whole-exome sequencing to identify pathogenic somatic mutations. Mutations with variant allele frequency less than 5% were validated by ultra-deep sequencing.

RESULTS

A total of 67 pediatrics (33 males, 34 females, age range: 0.1-14.8 years) were analyzed. Exome sequencing identified somatic mutations of corresponding genes in 53 patients, yielding a molecular diagnosis rate of 79.1%. Among 29 PIK3CA mutations, 17 were well-known hotspot p.E542K, p.E545K and p.H1047R/L. Non-hotspot mutations were prevalent in patients with PIK3CA-related overgrowth spectrum, accounting for 50.0% (11/22) of detected mutations. The hotspot GNAQ p.R183Q and TEK p.L914F mutations were responsible for the majority of port-wine stain/Sturge-Weber syndrome and venous malformation, respectively. In addition, we identified a novel AKT1 p.Q79K mutation in Proteus syndrome and MAP3K3 p.E387D mutation in verrucous venous malformation.

CONCLUSIONS

The somatic mutation spectrum of vascular malformations in Chinese population is similar to that reported in other populations, but non-hotspot PIK3CA mutations may also be prevalent. Molecular diagnosis may help the clinical diagnosis, treatment and management of these pediatric patients with vascular malformations.

Genetic testing in the evaluation of individuals with clinical diagnosis of atypical Sturge-Weber syndrome

Sturge-Weber Syndrome (SWS) is a rare vascular malformation disorder characterized by abnormal blood vessels in the brain, skin, and eye. SWS is most commonly caused by a somatic mosaic GNAQ-p.Arg183Gln variant. In this series, 12 patients presented for clinical evaluation of SWS but were noted to have atypical features, and therefore germline and/or somatic genetic testing was performed. Atypical features included extensive capillary malformation on the body as well as the face, frontal bossing, macrocephaly, telangiectasia, overgrowth of extremities, absence of neurologic signs and symptoms, and family history of vascular malformations. Five patients had a somatic GNAQ or GNA11 pathogenic variant, one patient had a somatic mosaic likely-pathogenic variant in PIK3CA, and another one had a somatic mosaic deletion that disrupted PTPRD. The other five patients had germline variants in RASA1, EPHB4, or KIT. Our findings suggest that patients presenting for SWS evaluation who have atypical clinical characteristics may have pathogenic germline or somatic variants in genes other than GNAQ or GNA11. Broad germline and somatic genetic testing in these patients with atypical findings may have implications for medical care, prognosis, and trial eligibility.

When, where and which PIK3CA mutations are pathogenic in congenital disorders

PIK3CA encodes the class I PI3Kα isoform and is frequently mutated in cancer. Activating mutations in PIK3CA also cause a range of congenital disorders featuring asymmetric tissue overgrowth, known as the PIK3CA-related overgrowth spectrum (PROS), with frequent vascular involvement. In PROS, PIK3CA mutations arise postzygotically, during embryonic development, leading to a mosaic body pattern distribution resulting in a variety of phenotypic features. A clear skewed pattern of overgrowth favoring some mesoderm-derived and ectoderm-derived tissues is observed but not understood. Here, we summarize our current knowledge of the determinants of PIK3CA-related pathogenesis in PROS, including intrinsic factors such as cell lineage susceptibility and PIK3CA variant bias, and extrinsic factors, which refers to environmental modifiers. We also include a section on PIK3CA-related vascular malformations given that the vasculature is frequently affected in PROS. Increasing our biological understanding of PIK3CA mutations in PROS will contribute toward unraveling the onset and progression of these conditions and ultimately impact on their treatment. Given that PIK3CA mutations are similar in PROS and cancer, deeper insights into one will also inform about the other.

Anastomosing Haemangioma: Report of Three Cases With Molecular and Immunohistochemical Studies and Comparison With Well-Differentiated Angiosarcoma

Anastomosing haemangioma (AH) is a newly described distinct vascular neoplasm that histologically may confuse with well-differentiated angiosarcoma (AS) for those who are unfamiliar with this rare entity. We aimed to identify molecular genetic differences between AHs and ASs by carrying out immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and next-generation sequencing (NGS). Immunohistochemically, all six cases showed positivity for cyclinD1 and pERK. All cases of AH showed focal weak positive reaction for p53 and MIB-1, and the IHCs for HIF-1α were all negative for all three cases. Those three cases of angiosarcoma revealed strong, diffuse positivity for p53, 50%–70% MIB-1 labelling, and multifocal, moderate to strong HIF-1α expression. To further clarify the difference in p53 expression, we carried out a FISH which revealed 17p polysomy in all three ASs whereas copy number aberration was absent in the AH group. In one AH case, the GNA11 c.627G > T nucleotide variant was detected. Due to the rarity and overlapping morphological features, AH might be difficult to separate from other vascular tumours, in particular from well-differentiated AS also featured by mild hyperchromatic, hobnail-like endothelial cells. The potential molecular differences between these two entities presented here may be used in support of the correct diagnosis.

How we approach complex vascular anomalies and overgrowth syndromes

Vascular anomalies, both vascular tumors and vascular malformations, can occur in isolation or as part of syndromes including those which feature phenotypic overgrowth. To update what is known about vascular anomalies associated with overgrowth, PubMed was searched for "overgrowth syndromes and vascular anomalies or malformations." PubMed, OMIM, and the Rare Disease Database also were searched for specific diagnoses. We review individual overgrowth syndromes, provide a case-based approach to the clinical, radiographic, pathologic, and genetic basis for diagnosis, to complications of both the vascular anomalies and the overgrowth, and emphasize the need for a multidisciplinary approach to care.

Clinical and Molecular Spectrum of Sporadic Vascular Malformations: A Single-Center Study

Sporadic vascular malformations (VMs) are a large group of disorders of the blood and lymphatic vessels caused by somatic mutations in several genes—mainly regulating the RAS/MAPK/ERK and PI3K/AKT/mTOR pathways. We performed a cross-sectional study of 43 patients affected with sporadic VMs, who had received molecular diagnosis by high-depth targeted next-generation sequencing in our center. Clinical and imaging features were correlated with the sequence variants identified in lesional tissues. Six of nine patients with capillary malformation and overgrowth (CMO) carried the recurrent GNAQ somatic mutation p.Arg183Gln, while two had PIK3CA mutations. Unexpectedly, 8 of 11 cases of diffuse CM with overgrowth (DCMO) carried known PIK3CA mutations, and the remaining 3 had pathogenic GNA11 variants. Recurrent PIK3CA mutations were identified in the patients with megalencephaly–CM–polymicrogyria (MCAP), CLOVES, and Klippel–Trenaunay syndrome. Interestingly, PIK3CA somatic mutations were associated with hand/foot anomalies not only in MCAP and CLOVES, but also in CMO and DCMO. Two patients with blue rubber bleb nevus syndrome carried double somatic TEK mutations, two of which were previously undescribed. In addition, a novel sporadic case of Parkes Weber syndrome (PWS) due to an RASA1 mosaic pathogenic variant was described. Finally, a girl with a mild PWS and another diagnosed with CMO carried pathogenic KRAS somatic variants, showing the variability of phenotypic features associated with KRAS mutations. Overall, our findings expand the clinical and molecular spectrum of sporadic VMs, and show the relevance of genetic testing for accurate diagnosis and emerging targeted therapies.

GNA11-mutated Sturge-Weber Syndrome has distinct neurologic and dermatologic features

BACKGROUND

Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by clinical manifestations involving the brain, eye and skin. SWS is commonly caused by somatic mutations in G protein subunit Alpha Q (GNAQ). Subunit Alpha 11 (GNA11) mutations have been reported in 5 cases. It is not clear if their phenotypic features differ.

METHODS

Within two European multidisciplinary centers we looked for patients with clinical characteristics of SWS and a GNA11 mutation. Clinical and radiological data was collected retrospectively and prospectively.

RESULTS

We identified three patients with SWS associated with a somatic GNA11 mutation. They had disseminated capillary malformation (CM) and hyper- or hypotrophy of an extremity. At birth, the CMs of the face, trunk and limbs were pink and patchy, and slowly darkened with age evolving to purple color. Two of the patients had glaucoma. All had neurological symptoms and moderate brain atrophy at a lower degree of severity than classically associated with SWS. Susceptibility-Weighted Images (SWI) and contrast-enhanced (CE) Fluid Attenuated Inversion Recovery (FLAIR) MR views demonstrated best sensitivity to reveal the pial angiomas.

CONCLUSIONS

We differentiate two distinct clinical/radiological phenotypes of SWS; GNAQ- and GNA11-SWS. The classical GNAQ-SWS is characterized by a homogeneous dark-red CM commonly associated with underlying soft tissue hypertrophy. The CM in GNA11-SWS is more reticulate and darkens with time; neurological picture is milder. SWI and post contrast FLAIR sequences appear to be necessary to demonstrate the leptomeningeal angiomatosis. Yet, anti-epileptic medication or future targeted therapies may be useful, like in classic SWS.

Molecular Pathways and Possible Therapies for Head and Neck Vascular Anomalies

Vascular Anomalies are a heterogenous group of vascular lesions that can be divided, according to the International Society for the Study of Vascular Anomalies Classification, into two main groups : Vascular Tumors and Vascular Malformations. Vascular Malformations can be further subdivided into slow-flow and fast-flow malformations. This clinical and radiological classification allows for a better understanding of vascular anomalies and aims to offer a more precise final diagnosis. Correct diagnosis is essential to propose the best treatment, which traditionally consists of surgery, embolization or sclerotherapy. Since a few years, medical treatment has become an important part of multidisciplinary treatment. Genetic and molecular knowledge of vascular anomalies are increasing rapidly and opens the door for a molecular classification of vascular anomalies according to the underlying pathways involved. The main pathways seem to be: PI3K/AKT/mTOR (PIKopathies) and RAS/RAF/MEK/ERK (RASopathies). Knowing the underlying molecular cascades allows us to use targeted medical therapies. The first part of this article aims to review the vascular anomalies seen in the head and neck region and their underlying molecular causes and involved pathways. The second part will propose an overview of the available targeted therapies based on the affected molecular cascade. This article summarizes theragnostic treatments available in vascular anomalies.

The Genetics of Vascular Birthmarks

One in ten infants are born with a vascular birthmark each year. Some vascular birthmarks, such as infantile hemangiomas, are common, while vascular malformations, such as capillary, lymphatic, venous, and arteriovenous malformations, are less so. Diagnosing uncommon vascular birthmarks can be challenging, given the phenotypic heterogeneity and overlap amongst these lesions. Both sporadic and germline variants have been detected in various genes associated with vascular birthmarks. Identification of these genetic variants offers insight into both diagnosis and underlying molecular pathways and can be fundamental in the discovery of novel therapeutic approaches. The PIK3/AKT/mTOR and RAS/MEK/ERK signaling pathways, which mediate cell growth and angiogenesis, are activated secondary to genetic variations in vascular malformations. Somatic variants in TEK (TIE2) and PIK3CA cause venous malformations. Variants in PIK3CA also cause lymphatic malformations as well as a number of overgrowth syndromes associated with vascular anomalies. Variants in GNAQ and GNA11 have been identified in both so-called "congenital" hemangiomas and capillary malformations. RASA1 and EPHB4 variants are associated with capillary malformation-arteriovenous malformation syndrome. This review discusses the genetics of vascular birthmarks including the various phenotypes, genetic variants, pathogenesis, associated syndromes, and new diagnostic techniques.

Vascular lesions of the pediatric orbit: A radiological walkthrough

Vascular anomalies of the pediatric orbit represent a heterogeneous group that include both vascular tumors and vascular malformations. The disorder may initially be silent and then associated with symptoms and/or function damage, depending on the type of vascular anomaly and its extension. Vascular tumors include benign, locally aggressive (or borderline) and malignant forms while vascular malformations are divided into "simple", "combined" and syndromic, or "low flow" or "high flow". Both entities can arise in isolation or as part of syndromes. In this review, we describe the imaging findings of the vascular lesions of the orbit in the pediatric population, which are key to obtain a correct diagnosis and to guide the appropriate treatment in the light of the new genetic and molecular discoveries, and the role of the radiologist in their multidisciplinary management. We will also touch upon the main syndromes associated with orbital vascular abnormalities.

Endothelial GNAQ p.R183Q Increases ANGPT2 (Angiopoietin-2) and Drives Formation of Enlarged Blood Vessels

OBJECTIVE

Capillary malformation (CM) occurs sporadically and is associated with Sturge-Weber syndrome. The somatic mosaic mutation in GNAQ (c.548G>A, p.R183Q) is enriched in endothelial cells (ECs) in skin CM and Sturge-Weber syndrome brain CM. Our goal was to investigate how the mutant Gαq (G-protein αq subunit) alters EC signaling and disrupts capillary morphogenesis. Approach and Results: We used lentiviral constructs to express p.R183Q or wild-type GNAQ in normal human endothelial colony forming cells (EC-R183Q and EC-WT, respectively). EC-R183Q constitutively activated PLC (phospholipase C) β3, a downstream effector of Gαq. Activated PLCβ3 was also detected in human CM tissue sections. Bulk RNA sequencing analyses of mutant versus wild-type EC indicated constitutive activation of PKC (protein kinase C), NF-κB (nuclear factor kappa B) and calcineurin signaling in EC-R183Q. Increased expression of downstream targets in these pathways, ANGPT2 (angiopoietin-2) and DSCR (Down syndrome critical region protein) 1.4 were confirmed by quantitative PCR and immunostaining of human CM tissue sections. The Gαq inhibitor YM-254890 as well as siRNA targeted to PLCβ3 reduced mRNA expression levels of these targets in EC-R183Q while the pan-PKC inhibitor AEB071 reduced ANGPT2 but not DSCR1.4. EC-R183Q formed enlarged blood vessels in mice, reminiscent of those found in human CM. shRNA knockdown of ANGPT2 in EC-R183Q normalized the enlarged vessels to sizes comparable those formed by EC-WT.

CONCLUSIONS

Gαq-R183Q, when expressed in ECs, establishes constitutively active PLCβ3 signaling that leads to increased ANGPT2 and a proangiogenic, proinflammatory phenotype. EC-R183Q are sufficient to form enlarged CM-like vessels in mice, and suppression of ANGPT2 prevents the enlargement. Our study provides the first evidence that endothelial Gαq-R183Q is causative for CM and identifies ANGPT2 as a contributor to CM vascular phenotype.

Segmental undergrowth is associated with pathogenic variants in vascular malformation genes: A retrospective case-series study

Segmental overgrowth has been widely described in patients with congenital vascular anomalies. However, segmental undergrowth has been poorly characterized, and no large series of patients have been published. We present the clinical and molecular characteristics a cohort of 37 patients with vascular malformations and segmental undergrowth. True undergrowth was only considered when the musculoskeletal system was involved to avoid confusion with other causes of segmental reduction, as in lipodystrophy or the long-term osteopenia seen in patients with Servelle-Martorell syndrome. Deep high-throughput sequencing was performed in tissue samples from 20 patients using a custom panel. We identified three groups: undergrowth associated with (1) venous, (2) capillary-venous, and (3) lymphatic-capillary-venous malformations. Congenital or early childhood onset undergrowth can occur with or without associated overgrowth. Different likely pathogenic or pathogenic variants were detected in 13 of 20 (65%) tissue samples in the PIK3CA, TEK, GNAQ, or GNA11 genes. In conclusion, the eponymous Servelle-Martorell syndrome should not be used as a synonym for undergrowth. Segmental undergrowth should be considered a characteristic associated with vascular malformations. Patients with PIK3CA variants show all different combinations of overgrowth and undergrowth. Thus, the term PROS (PIK3CA-related overgrowth spectrum) does not cover the entire spectrum.

GNA14's interaction with RACK1 inhibits hepatocellular carcinoma progression through reducing MAPK/JNK and PI3K/AKT signaling pathway

Gαq subfamily proteins play critical roles in many biological functions including cardiovascular development, angiogenesis, and tumorigenesis of melanoma. However, the understanding of G Protein Subunit Alpha 14 (GNA14) in diseases, especially in cancers is limited. Here, we revealed that GNA14 was significantly low expression in Human hepatocellular carcinoma (HCC) samples. Low GNA14 expression was correlated with aggressive clinicopathological features. Moreover, the overall survival (OS) and disease-free survival (DFS) of high GNA14 expression HCC patients were much better than low GNA14 expression group. Lentivirus-mediated GNA14 knockdown significantly promoted the growth of liver cancer in vitro and in vivo. However, opposing results were observed when GNA14 is upregulated. Mechanistically, We identified receptor for activated C kinase 1 (RACK1) as a binding partner of GNA14 by co-immunoprecipitation and mass spectrometry (MS). Glutathione-S-transferase (GST) pull-down assay further verified the direct interaction between GNA14 and RACK1. RNA-Seq and loss- and gain-of-function assays also confirmed that GNA14 reduced the activity of both MAPK/JNK and PI3K/AKT signaling pathways through RACK1. GNA14 synergized with U73122 (PLC inhibitor) to enhance this effect. Further studies suggested that GNA14 potentially competed with protein kinase C (PKC) to bind with RACK1, consequently reducing the stability of PKC. Moreover, we also showed that GNA14’supression of p-AKT protein level depended on sufficient RACK1 expression. In conclusion, we indicated a different role of GNA14, which acted as a suppressor inhibiting liver cancer progression through MAPK/JNK and PI3K/AKT signaling pathways. Due to this, GNA14 served as a potentially valuable prognostic biomarker for liver cancer.

Identification and Evaluation of Autoantibody to a Novel Tumor-Associated Antigen GNA11 as a Biomarker in Esophageal Squamous Cell Carcinoma

The study aims to explore the diagnostic value of anti-GNA11 autoantibody in esophageal squamous cell carcinoma (ESCC) from multiple levels. Autoantibody against GNA11 with the highest diagnostic performance was screened out from the customized protein microarray. A total of 486 subjects including ESCC patients and matched normal controls were recruited in the verification and validation phases by using enzyme-linked immunosorbent assay (ELISA). Western blotting analysis was used to verify the ELISA results. Immunohistochemistry (IHC) was used to evaluate GNA11 expression in ESCC tissues and para-tumor tissues. In addition, a bioinformatics approach was adopted to investigate the mRNA expression of GNA11 in ESCC. Results indicated that the level of anti-GNA11 autoantibody in ESCC patients was significantly higher than that in the normal controls, and it can be used to distinguish ESCC patients from normal individuals in clinical subgroups (p < 0.05), as revealed by both ELISA and Western blotting. The receiver operating characteristic (ROC) curve analysis showed that anti-GNA11 autoantibody could distinguish ESCC patients from normal controls with an area under the ROC curve (AUC) of 0.653, sensitivity of 10.96%, and specificity of 98.63% in the verification cohort and with an AUC of 0.751, sensitivity of 38.24%, and specificity of 88.82% in the validation cohort. IHC manifested that the expression of GNA11 can differentiate ESCC tissues with para-tumor tissues (p < 0.05), but it cannot be used to differentiate different pathological grades and clinical stages (p > 0.05). The mRNA expression of GNA11 in ESCC patients and normal controls was different with a bioinformatics mining with The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data in Gene Expression Profiling Interactive Analysis (GEPIA). In summary, anti-GNA11 autoantibody has the potential to be a new serological marker in the diagnosis of ESCC.

Therapeutic Strategies for Untreated Capillary Malformations of the Head and Neck Region: A Systematic Review and Meta-Analyses

Background

Capillary malformations of the head and neck region often cause psychological and physical burden. As the effectiveness of modern laser and light therapies is still suboptimal, patients often seek different therapeutic strategies. Other recognized, but not routinely proposed therapies include cosmetic camouflage, surgery, and medical tattooing. Information on therapeutic outcomes is currently lacking for patients to adequately participate in the treatment decision-making process.

Objective

The objective of this systematic review was to review the effectiveness and safety of recognized therapies for untreated capillary malformations of the head and neck: laser and light treatment modalities, photodynamic therapy, cosmetic camouflage, medical tattooing, and surgery.

Methods

PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched up to 16 December, 2020 for observational and experimental studies examining recognized therapies for untreated capillary malformations of the head and neck. Two reviewers independently evaluated the risk of bias of included studies. Predefined treatment and safety outcomes of pooled data were scored using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Results

We included 48 observational and three randomized studies (totaling 3068 patients), evaluating nine different therapies. No studies on surgery or cosmetic camouflage matched our inclusion criteria. The pooled proportion of patients reaching a ≥75% clearance was 43% (95% confidence interval 24–64%; I² = 55%) for the pulsed dye laser after three to eight treatment sessions (GRADE score: very low). Other therapies were less effective. Hyperpigmentation was most frequently described after the pulsed dye laser (incidences up to 40%). Pain was most common after photodynamic therapy, yet the intensity was unreported. Substantial heterogeneity among studies as to patient characteristics and outcomes limited pooling and data comparisons.

Conclusions

The pulsed dye laser seems preferable for treatment-naive capillary malformations of the head and neck region, yet demonstrates greater hyperpigmentation rates compared with other therapies. Our results are, however, based on low-quality evidence. Future studies using uniform outcome measures and validated metrics are warranted for study comparability. Based on this systematic review, clinicians and patients should be aware of the limited evidence about the available options when making (shared) treatment decisions for capillary malformations.

Trial Registration

Review registration number PROSPERO database: CRD42020199445.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40257-021-00616-5.

Congenital vascular lesions, could MAPK and PI3K inhibitors pave the way to new therapies?

PURPOSE OF REVIEW

Superficial vascular anomalies are a heterogeneous group of malformative and tumoral lesions, developed from various types of abnormal lymphatic and/or blood vessels. They are mostly benign but their clinical evolution can lead to dramatic cosmetic concern, functional impairment and even life-threatening conditions. Until recently, treatments relied on invasive procedures such as embotherapy/sclerotherapy and/or surgery. Recent molecular findings pave the way of new medical therapies.

RECENT FINDINGS

Two main signaling pathways PI3K-AKT-mTOR and RAS-MAPK-ERK are now identified to encounter for the causative pathogenic genetic variants of most vascular anomalies. Involved genes are also responsible for several common neoplasms for which targeted therapies are already available or under development. Repurposing treatment strategy is considered for vascular anomalies treatment with promising results.

SUMMARY

The mTOR inhibitor sirolimus is the most used targeted therapy so far but new molecules are tested currently.

Genetic syndromes with vascular malformations - update on molecular background and diagnostics

Vascular malformations are present in a great variety of congenital syndromes, either as the predominant or additional feature. They pose a major challenge to the clinician: due to significant phenotype overlap, a precise diagnosis is often difficult to obtain, some of the malformations carry a risk of life threatening complications and, for many entities, treatment is not well established. To facilitate their recognition and aid in differentiation, we present a selection of notable congenital disorders of vascular system development, distinguishing between the heritable germinal and sporadic somatic mutations as their causes. Clinical features, genetic background and comprehensible description of molecular mechanisms is provided for each entity.

Research trends, hot spots and prospects for necroptosis in the field of neuroscience

There are two types of cell death-apoptosis and necrosis. Apoptosis is cell death regulated by cell signaling pathways, while necrosis has until recently been considered a passive mechanism of cell death caused by environmental pressures. However, recent studies show that necrosis can also be regulated by specific cell signaling pathways. This mode of death, termed necroptosis, has been found to be related to the occurrence and development of many diseases. We used bibliometrics to analyze the global output of literature on necroptosis in the field of neuroscience published in the period 2007–2019 to identify research hotspots and prospects. We included 145 necroptosis-related publications and 2239 references published in the Web of Science during 2007–2019. Visualization analysis revealed that the number of publications related to necroptosis has increased year by year, reaching a peak in 2019. China is the country with the largest number of publications. Key word and literature analyses demonstrated that mitochondrial function change, stroke, ischemia/reperfusion and neuroinflammation are likely the research hotspots and future directions of necroptosis research in the nervous system. The relationship between immune response-related factors, damage-associated molecular patterns, pathogen-associated molecular patterns and necroptosis may become a potential research hotspot in the future. Taken together, our findings suggest that although the inherent limitations of bibliometrics may affect the accuracy of the literature-based prediction of research hotspots, the results obtained from the included publications can provide a reference for the study of necroptosis in the field of neuroscience.

Genes and phenotypes in vascular malformations

Vascular malformations (VMs) are caused by localized defects of vascular development. Most VMs are due to sporadic, postzygotic mutations, while some are the result of autosomal dominant germline mutations. Genotype-phenotype correlation is influenced by many factors. Individual genes can induce different phenotypes (pleiotropy), and similar phenotypes can be due to different genes/mutations (redundancy). The phenotypic spectrum of somatic mutations is wide, and depends on variant allele frequency, timing during embryogenesis, cell type(s) involved and type of mutation. The phenotype of germline mutations is determined by penetrance and expressivity, and is influenced by epigenetic factors (DNA methylation, histone modification) or 'second-hit' somatic mutations. Except for disorders with pathognomonic phenotypes such as Proteus syndrome or a characteristic constellation of symptoms such as CLOVES [congenital lipomatous (fatty) overgrowth, vascular malformations, epidermal naevi and scoliosis/skeletal/spinal anomalies] or PIK3CA-related overgrowth spectrum syndrome, differential diagnosis of VM is therefore difficult. It will be greatly facilitated with increasing analytic sensitivity of sequencing techniques such as next-generation sequencing. High-sensitivity molecular techniques are a prerequisite for targeted pharmacotherapy, i.e. selective therapeutic inhibition of activating mutations underlying VM, which has shown promising results in preliminary studies.

[Classification of vascular tumours and vascular malformations. Contribution of the ISSVA 2014/2018 classification]

The study of vascular anomalies, "angiomas", vascular tumours and vascular malformations is made difficult by the great variety and confusion of the names used in the literature for these diseases, some of which are rare. The great merit of the classification proposed by the International Society for the Study of Vascular Anomalies (ISSVA), adopted in 2014 and modified in 2018, is to propose a unambiguous nomenclature and to try to group these lesions in a logical way, contrasting with the lists of the usual "classifications". This classification is based on the distinction between proliferative lesions (tumours and reactive lesions) and those which are due to a congenital anomaly of vascular morphogenesis (vascular malformations). It incorporates recent data on the molecular causes of these diseases. The major groups of lesions recognised in this classification will be presented and some lesions of interest briefly discussed. This classification aims to be usable by all medical specialties and applicable to all tissues and organs, even if efforts are still needed to integrate organ-specific names in order to unify the nomenclature and eliminate confusion. Even if it does not solve all the problems in this complex field, the unification of the nomenclature is a major contribution of this classification and pathologists are strongly encouraged to refer to it in daily practice.

Functional characterization of uveal melanoma oncogenes

Uveal melanoma (UM) is a currently untreatable form of melanoma with a 50% mortality rate. Characterization of the essential signaling pathways driving this cancer is critical to develop target therapies. Activating mutations in the Gαq signaling pathway at the level of GNAQ, GNA11, or rarely CYSLTR2 or PLCβ4 are considered alterations driving proliferation in UM and several other neoplastic disorders. Here, we systematically examined the oncogenic signaling output of various mutations recurrently identified in human tumors. We demonstrate that CYSLTR2 → GNAQ/11 → PLCβ act in a linear signaling cascade that, via protein kinase C (PKC), activates in parallel the MAP-kinase and FAK/Yes-associated protein pathways. Using genetic ablation and pharmacological inhibition, we show that the PKC/RasGRP3/MAPK signaling branch is the essential component that drives the proliferation of UM. Only inhibition of the MAPK branch but not the FAK branch synergizes with inhibition of the proximal cascade, providing a blueprint for combination therapy. All oncogenic signaling could be extinguished by the novel GNAQ/11 inhibitor YM-254890, in all UM cells with driver mutation in the Gαq subunit or the upstream receptor. Our findings highlight the GNAQ/11 → PLCβ → PKC → MAPK pathway as the central signaling axis to be suppressed pharmacologically to treat for neoplastic disorders with Gαq pathway mutations.

Skin-Related complications of Klippel-Trenaunay Syndrome: a retrospective review of 410 patients

BACKGROUND

Little is known about skin-related complications in Klippel-Trenaunay syndrome (KTS), a complex vascular anomaly defined by capillary malformation (CM), venous malformation (VM) ± lymphatic malformation (LM) and limb overgrowth. Reported skin-related complications of KTS include ulceration, vascular ectasias (blebs), bleeding and infection.

OBJECTIVE

To determine the spectrum, prevalence and predictors of skin-related complications in KTS.

METHODS

A retrospective review of 410 patients fulfilling KTS criteria was performed to assess for the presence of skin-related complications.

RESULTS

Skin-related complications were present in 45% of patients. Most prevalent were CM-related complications including blebs, bleeding, thickening (25%), cellulitis (22%) and ulceration (21%). Features positively associated with skin-related complications were presence of LM (OR 17.17; P < 0.001), VM on the buttocks/perineum/genitalia (OR 1.92; P = 0.009), CM on the feet (OR 1.77; P = 0.039) and male sex (OR 1.63; P = 0.034). Features negatively associated with skin-related complications were CM on the trunk (OR 0.59; P = 0.029) and tissue hypertrophy of the hands (OR 0.27; P = 0.025).

CONCLUSION

Skin-related complications affect nearly half of patients with KTS. Those with lymphatic involvement or malformation presence in the undergarment area or feet are most at risk.

Infantile and congenital hemangiomas

Infantile hemangiomas (IHs) are the most common benign tumors of infancy. They typically appear after birth and undergo a period of rapid growth, followed by a gradual period of involution. Although the majority of IHs do not requirement treatment, oral propranolol is the first-line therapy for lesions that are at risk for life-threatening complications, functional impairment, ulceration, or permanent disfigurement. Rarely, IHs can be associated with structural anomalies. Congenital hemangiomas (CHs) are a distinct clinical entity, caused by a point mutation in GNAQ or GNA11. These lesions are typically present at birth and display a wide spectrum of clinical presentations. CHs can be distinguished from IHs by their unique histologic and radiographic features. Given the high-flow vascularity of CHs, surgical excision may be indicated due to the high risk of bleeding.

Genetics of vascular anomalies

Vascular anomalies are developmental defects of the vasculature and encompass a variety of disorders. The identification of genes mutated in the different malformations provides insight into the etiopathogenic mechanisms and the specific roles the associated proteins play in vascular development and maintenance. A few familial forms of vascular anomalies exist, but most cases occur sporadically. It is becoming evident that somatic mosaicism plays a major role in the formation of vascular lesions. The use of Next Generating Sequencing for high throughput and "deep" screening of both blood and lesional DNA and RNA has been instrumental in detecting such low frequency somatic changes. The number of novel causative mutations identified for many vascular anomalies has soared within a 10-year period. The discovery of such genes aided in unraveling a holistic overview of the pathogenic mechanisms, by which in vitro and in vivo models could be generated, and opening the doors to development of more effective treatments that do not address just symptoms. Moreover, as many mutations and the implicated signaling pathways are shared with cancers, current oncological therapies could potentially be repurposed for the treatment of vascular anomalies.

Overgrowth syndromes and new therapies

Overgrowth syndromes represent a diverse group of disorders with overlapping features. Interdisciplinary management by a team of experts in vascular anomalies is crucial for establishing the correct diagnosis and optimizing outcomes for these patients. Unique management considerations include increased risk for thrombosis and in some cases, cancer. In recent years, research has demonstrated that these disorders are primarily caused by somatic mutations in growth pathways, particularly the PI3K-mTOR pathway. This improved understanding had led to promising new therapies for this group of patients.

Clinical and genetic evaluation of six children with diffuse capillary malformation and undergrowth

BACKGROUND

Diffuse capillary malformation with overgrowth (DCMO) has been well described. However, capillary malformation with undergrowth (CMU) has been less reported in the literature.

OBJECTIVES

We sought to describe the clinical features and determine associated somatic mutations in patients with CMU.

METHODS

We searched our multidisciplinary vascular anomalies clinic database for patients with CMU. Girth and length limb measurements were performed. In case of discrepancies in length, long leg radiograph studies were obtained. Whole-exome sequencing of blood and involved tissue DNA was carried out.

RESULTS

We included six patients with CM and soft-tissue and bone undergrowth. CMs were patchy, reticulated, segmental, poorly demarcated, pink-red stains affecting the lower limb (five patients) or the whole hemibody (one patient). In five patients, the stain was diffuse, affecting more than one anatomic region. Prominent superficial veins were observed in three patients. Five patients presented with lower limb girth discrepancy; in three of them, there was also lower limb length discrepancy. In the remaining patient, only lower limb length discrepancy was found. Whole-exome sequencing from DNA tissue/blood detected previously described pathogenic somatic mutations on DDR2 (c.314G > A; p.Arg105His), GRHL2 (c.791A > G; p.Glu264Gly), and PIK3CA (c.2740G > A; p.Gly914Arg) genes.

CONCLUSION

We propose the term "diffuse capillary malformation with undergrowth" for extensive reticular CMs associated with proportionate undergrowth. All our patients had a favorable outcome, and no genotype-phenotype association was found.

A somatic missense mutation in GNAQ causes capillary malformation

PURPOSE OF REVIEW

Capillary malformations, the most common type of vascular malformation, are caused by a somatic mosaic mutation in GNAQ, which encodes the Gαq subunit of heterotrimeric G-proteins. How the single amino acid change - predicted to activate Gαq - causes capillary malformations is not known but recent advances are helping to unravel the mechanisms.

RECENT FINDINGS

The GNAQ R183Q mutation is present not only in endothelial cells isolated from skin and brain capillary malformations but also in brain tissue underlying the capillary malformation, raising questions about the origin of capillary malformation-causing cells. Insights from computational analyses shed light on the mechanisms of constitutive activation and new basic science shows Gαq plays roles in sensing shear stress and in regulating cerebral blood flow.

SUMMARY

Several studies confirm the GNAQ R183Q mutation in 90% of nonsyndromic and Sturge-Weber syndrome (SWS) capillary malformations. The mutation is enriched in endothelial cells and blood vessels isolated from skin, brain, and choroidal capillary malformations, but whether the mutation resides in other cell types must be determined. Further, the mechanisms by which the R183Q mutation alters microvascular architecture and blood flow must be uncovered to develop new treatment strategies for SWS in particular, a devastating disease for which there is no cure.

The molecular pathophysiology of vascular anomalies: Genomic research

Vascular anomalies are congenital localized abnormalities that result from improper development and maintenance of the vasculature. The lesions of vascular anomalies vary in location, type, and clinical severity of the phenotype, and the current treatment options are often unsatisfactory. Most vascular anomalies are sporadic, but patterns of inheritance have been noted in some cases, making genetic analysis relevant. Developments in the field of genomics, including next-generation sequencing, have provided novel insights into the genetic and molecular pathophysiological mechanisms underlying vascular anomalies. These insights may pave the way for new approaches to molecular diagnosis and potential disease-specific therapies. This article provides an introduction to genetic testing for vascular anomalies and presents a brief summary of the etiology and genetics of vascular anomalies.

CD10 and CD34 as markers in vascular malformations with PIK3CA and TEK mutations

AIMS

Vascular malformations (vMs) encompass a wide range of diseases often associated with somatic or, more rarely, germinal genetic mutations. A mutation in the PIK3Ca/mTOR pathway is more often involved in various vMs. CD10 and CD34 are cellular markers that may play a role in mesenchymal differentiation and proliferation. The aim of our study was to find a possible link between the immunohistochemical expression of CD10 and CD34 in vMs and their relationship with mutations in the PIK3CA/mTOR signaling pathway.

METHODS AND RESULTS

Our study on 58 samples of vMs showed that in endothelial cells, CD10 was significantly expressed in PIK3CA-mutated samples compared with samples without any mutation (p < 0.05), especially and even more consistently when compared with samples with mutation in other pathways (p < 0.0001). Conversely, in the same PIK3CA-mutated samples, CD34 expression in endothelial cells was significantly reduced compared with samples either without any mutation or mutations in other pathways (p < 0.05 and p < 0.0005). Compared with samples with mutations in other pathways, a significant overexpression of endothelial CD10 was also found in samples with TEK/TIE2 mutation, a gene linked to the PIK3CA/mTOR pathway (p < 0.01). However, CD34 expression was not altered. In samples with PIK3CA mutation, the CD10 expression was significantly increased in the stroma compared with samples with TEK/TIE2 gene or other gene mutations (p < 0.05).

CONCLUSION

Therefore, the CD10 and CD34 immunohistochemical profile could suggest/support the presence of mutations in the PIK3CA/mTOR pathway in samples of vMs.