Von Hippel-Lindau Disease: A Genetic and Clinical Review

[Stereotactic irradiation for optic nerve hemangioblastoma associated with Von Hippel-Lindau disease: a case report and literature review]

Hemangioblastoma is a benign tumor of the central nervous system arising sporadically or as a component of Von Hippel-Lindau disease. Von Hippel-Lindau disease is a rare autosomal dominant hereditary syndrome with various phenotypes caused by VHL gene variants. To date, only about 40 cases of optic nerve hemangioblastoma have been described in the literature. Stereotactic irradiation may be effective for supratentorial hemangioblastomas including lesions of optic nerves. The authors describe a rare case of stereotactic irradiation of intraorbital hemangioblastoma of the optic nerve in a patient with Von Hippel-Lindau disease.

Characterization of Microscopic Multicellular Foci in Grossly Normal Renal Parenchyma of Von Hippel-Lindau Kidney

Background and Objectives: This study aims to describe the earliest renal lesions in patients with von Hippel-Lindau (VHL) disease, especially the multicellular microscopic pathologic events, to get information into the genesis of renal neoplasms in this condition. Materials and Methods: Multicellular events were identified, and 3dimensional reconstruction was performed in grossly normal kidney parenchyma from VHL disease patients by using H&E-stained slides previously prepared. Results: The lesions were measured and the volume of clusters was calculated. Immunohistochemistry was performed for downstream HIF-target protein carbonic anhydrase 9 (CAIX) as well as CD34 for assessment of angiogenesis. We divided lesions into four types according to lesion height/size. The number of lesions was markedly decreased from lesion 1 (smallest) to lesion 2, then from lesions 2 to 3, and again from lesion 3 to 4. Distribution was highly consistent in the four cases, and the same decrement pattern was seen in all blocks studied. The volumes of clusters were measured and divided into three categories according to their volume. The most frequent pathologic event in VHL kidneys was category 1 (smallest volume), then category 2, and then category 3. Conclusion: We demonstrate that tracking histologic and morphologic changes in 3 dimensions of multicellular microscopic pathologic events enabled us to confirm a protracted sequence of events from smaller to larger cellular amplification events in VHL kidney.

Von Hipple-Lindau disease complicated with central retinal vein occlusion: a case report

BACKGROUND

Central Retinal Vein Occlusion (CRVO) is a rare complication of von Hipple-Lindau (VHL) disease. This report presents the first case of VHL disease complicated with CRVO caused by VHL c.208G > A mutation.

CASE PRESENTATION

A 20 s man whose left eye visual acuity gradually declined for half a year. The visual acuity of the left eye is counting fingers. Fundus examination revealed that retinal hemangioblastoma was also found in addition to typical CRVO signs such as tortuous expansion of retinal veins and flame-shaped hemorrhage of the retina. Liver tumor, cerebral infarction and erythrocytosis were found during systemic examination, and the diagnosis of polycythemia was confirmed by bone marrow smear. Furthermore, both family history and genetic analysis indicated that the patient had VHL disease caused by VHL c.208G > A. In this patient, a large number of bone marrow erythrocytes proliferated due to VHL disease, which led to the increase of blood viscosity and erythrocyte vascular adhesion, resulting in the obstruction of central retinal vein blood flow, and finally CRVO. For CRVO and its pathogenic factor polycythemia, patient received laser retinal photocoagulation and phlebotomies. After a 1-year follow-up, the vision in the left eye improved to 0.2 logMAR.

CONCLUSIONS

This is a rare case of polycythemia complicated by CRVO in patient with VHL disease. It reminds us that the systemic disease factors should be fully considered in the diagnosis of young patients with CRVO, and that treatment requires a coordinated effort of physicians.

A meta-analysis of different von Hippel Lindau mutations: are they related to retinal capillary hemangioblastoma?

Retinal capillary hemangioblastomas (RCH) is a benign tumor that represents the initial manifestation in roughly half of Von Hippel Lindau (VHL) patients. They may also occur sporadically without systemic involvement. A first meta-analysis study was investigated to estimate the prevalence of Retinal capillary hemangioblastoma (RCH) in Von Hippel Lindau (VHL) syndrome, and its relation to type and location of mutations in VHL gene. The electronic databases of PubMed, Scopus, Embase, and Google Scholar were utilized to find eligible papers published up to May 2020. Lastly, after the different prevalence of RCH in Europe compared to other continents was noted, we decided to consider European and non-European patients separately. The Random effect model was used to evaluate the relation between developing RCH and types of mutations. The overall prevalence of RCH among VHL patients is about 47%. The prevalence of RCH was significantly higher in Europe in comparison with non-Europeans (p value < 0.001). Overall, the differences between the prevalence of RCH among different mutation types were not statistically significant. However, in Europe, the prevalence of RCH was significantly higher in patients with truncation mutation (p value = 0.007). In Europe, the RCH in VHL patients who had a mutation in exon 2 was significantly lower in comparison with exon 1 (p value = 0.001); but in non-Europeans, the prevalence of RCH in VHL patients that involved exon 2 was significantly higher in comparison with VHL patients with a mutation in exon1 (p value = 0.012). The highest risk of developing RCH was reported among Europeans. Overall, this study showed that the prevalence of RCH in VHL syndrome is not related to type or location of mutations and difference of RCH prevalence is probably depends on other genetic or environmental factor that should be considered in subsequent studies.

Combined therapy guided by multimodal imaging of fifteen retinal capillary hemangioblastomas in a monocular Von Hippel- Lindau syndrome case report

Background

To report the multimodal imaging and treatment of fifteen retinal capillary hemangioblastomas (RCHs) associated with Von Hippel-Lindau syndrome in a monocular patient during a long-term following-up, which supply high-resolution exquisite SS-OCTA images (VG200; SVision Imaging, Ltd., Luoyang, China) and management experience about multiple RCHs.

Case presentation

A 34-year-old monocular male patient complained decreased visual acuity (20/100) without pain and redness in the left eye five years ago. Von Hippel-Lindau syndrome were diagnosed with genetic testing. He, his son and daughter all carried a heterozygosity missense variant c.499C > T (p. Arg167Trp) in the Hg19 gene, a VHL gene located in Chr3:10,191,506. Fifteen RCHs were identified by the application of multimodal imaging, which including fundus photo, fundus autofluorescence (FAF), B-scan ultrasonography (US), fluorescein fundus angiography (FFA), indocyanine green angiography (ICGA) and swept-source optical coherence tomography angiography (SS-OCTA). Transscleral cryotherapy and laser photocoagulation were performed to destroy the largest RCH with the size of 4 PD in diameter. Laser photocoagulation was conducted to seal the middle or tiny RCHs (< 1.5 PD) and their nourishing vessels. The retinal edema and exudative macular detachment were successfully relieved by intraocular injection of bevacizumab for 5 times. The RCHs in the left eye responded well to these treatments and best corrected visual acuity was 20/25 for three years. Three-month recall visits were recommended for him.

Conclusion

For multiple retinal capillary hemangioblastomas in monocular patients, precise combined therapy guided by multimodal imaging has a profound impact on the management of new and recurrent RCHs.

The Role of Propranolol as a Repurposed Drug in Rare Vascular Diseases

Rare Diseases (RD) are defined by their prevalence in less than 5 in 10,000 of the general population. Considered individually, each RD may seem insignificant, but together they add up to more than 7000 different diseases. Research in RD is not attractive for pharmaceutical companies since it is unlikely to recover development costs for medicines aimed to small numbers of patients. Since most of these diseases are life threatening, this fact underscores the urgent need for treatments. Drug repurposing consists of identifying new uses for approved drugs outside the scope of the original medical indication. It is an alternative option in drug development and represents a viable and risk-managed strategy to develop for RDs. In 2008, the “off label” therapeutic benefits of propranolol were described in the benign tumor Infantile Hemangioma. Propranolol, initially prescribed for high blood pressure, irregular heart rate, essential tremor, and anxiety, has, in the last decade, shown increasing evidence of its antiangiogenic, pro-apoptotic, vasoconstrictor and anti-inflammatory properties in different RDs, including vascular or oncological pathologies. This review highlights the finished and ongoing trials in which propranolol has arisen as a good repurposing drug for improving the health condition in RDs.

Case Report of a Hemangioblastoma With Large Blood Vessels and Rare Vascular Anomalies: Is It Fibromuscular Dysplasia or Arteriovenous Malformation Association?

Hemangioblastoma is considered a benign neoplasm characterized by abnormal vasculature and stromal cells; several pathophysiological mechanisms have been proposed, such as genetic predisposition, hormonal factors, and arterial wall ischemia. Fibromuscular dysplasia is characterized by hyperplasia or thinning of the smooth muscle, elastic fibre destruction, fibrous tissue proliferation, and arterial wall disorganization. We present a cerebellar hemangioblastoma case not associated with Von Hippel Lindau syndrome. Histologically we evidenced big vessels with anomalies of the vascular walls corresponding to fibromuscular dysplasia, and those changes have not been described in these types of tumors. In this light, rare findings could be called vascular malformations or degenerative vascular changes, fibromuscular dysplasia or vascular anomalies. Arterio-venous malformation and hemangioblastoma pathology are rarely presented together. Notwithstanding, we could say that it is a stromal stem cell tumor in a varied stage of differentiation.

Efficacy and safety of current treatment options for peripheral retinal haemangioblastomas: a systematic review

IMPORTANCE

Approximately twenty per cent of Von Hippel-Lindau patients with retinal haemangioblastomas (RH) suffer from visual impairment. Various treatment options are available for peripheral RH. However, management of peripheral RH is complex due to multifocality and bilaterality.

OBJECTIVE

To summarize published evidence on efficacy and safety of different interventions for peripheral RH and to provide treatment recommendations for specialists.

EVIDENCE REVIEW

Comprehensive searches were performed using Medline, Embase, Web of Science and Google Scholar database on 4 March 2020. English publications that described outcomes related to efficacy or complications in at least two patients with peripheral RH were included. Efficacy and safety were estimated by complete tumour eradication rate, pretherapeutic and treatment-related complication rate. Odds ratios (OR) with 95% confidence intervals (CI) were calculated to calculate the risk estimate of complications between treatment options.

FINDINGS

Twenty-seven articles were included in this review describing nine different treatment options for peripheral RH: laser photocoagulation (n = 230), cryotherapy (n = 50), plaque radiotherapy (n = 27), vitreoretinal surgery (n = 88), photodynamic therapy (PDT; n = 14), transpupillary thermotherapy (TTT; n = 10), external beam radiotherapy (n = 3), systemic treatment (n = 7) and intravitreal anti-VEGF (n = 2). Complete tumour eradication was achieved in 86.7% (95% CI: 83.5-89.9%) of all eyes. For the different treatments, this was after laser photocoagulation 89.9% (86.1-93.7%), cryotherapy 70.2% (57.0-83.4%), plaque radiotherapy 96.3% (89.1-100.0%), vitreoretinal surgery (100.0%), PDT 64.3% (38.3-90.3%) and TTT 80.0% (53.8-100.0%). No complete tumour eradication was achieved after systemic therapy, external beam radiotherapy or intravitreal anti-VEGF. Photodynamic therapy and vitreoretinal surgery showed the highest complication rate after treatment compared to the other treatments (OR 10.5 [95% CI: 2.9-38.4]) and (OR 5.9 [95% CI: 3.4-9.9]), respectively. Cases that had pretherapeutic complications showed a higher treatment-related complication rate (OR 14.8 [95% CI: 7.3-30.0]) than cases without complications before treatment.

CONCLUSIONS AND RELEVANCE

These findings suggest that laser photocoagulation is the safest and most effective treatment method for peripheral RH up to 1.5 mm in diameter. Vitreoretinal surgery has the highest success rate for complete tumour eradication and may be the most suitable treatment option in the presence of pretherapeutic complications and for larger tumours.

Hemangioblastoma of the Peripheral Nervous System: A Critical Analysis of Its Rarity in Von Hippel-Lindau Disease

Von Hippel-Lindau (VHL) disease is a multisystem disease cause by germline mutations of the VHL tumor suppressor gene. Hemangioblastomas are the most common manifestation of VHL disease and can occur in the central nervous system in up to 90% of these patients. By contrast, we found only one true case of a peripheral nervous system (PNS) hemangioblastoma in the setting of VHL. We explore the possible reasons behind the lack of PNS hemangioblastomas in VHL disease.

Ophthalmological Aspects of von-Hippel-Lindau Syndrome

Background: von Hippel-Lindau (VHL) syndrome is a multisystem neoplastic disorder involving eyes, central nervous system, kidneys, spine, and other tissues. A retinal capillary hemangioma (RCH) is the earliest manifestation of the VHL disease in most cases.Areas covered:This paper aims to provide an up-to-date review of the current literature about von Hippel-Lindau syndrome. Molecular background, systemic and ocular features of the diseases as well as the utility of newer imaging modalities in diagnosis and monitoring of ocular VHL disease have been described. Besides, we have discussed newer treatment modalities and therapeutic targets.Conclusion: Modern imaging technologies like optical coherence tomography and optical coherence tomography angiography are tools of the trade, in making an appropriate diagnosis and monitoring disease activity and response to treatment. Peripheral RCH may be treated using laser photocoagulation in tumors up to 3000 µm. Vascular endothelial growth factor suppression can help in reducing tumor activity and stabilize the tumor size; however, it does not regress the RCH.

The Genotype-Phenotype Association of Von Hipple Lindau Disease Based on Mutation Locations: A Retrospective Study of 577 Cases in a Chinese Population

Purpose

Von Hippel-Lindau (VHL) disease is a hereditary kidney cancer syndrome, with which patients are more likely to get affected by renal cell carcinoma (RCC), pancreatic cyst or tumor (PCT), central nervous system hemangioblastoma (CHB), retinal angiomas (RA), and pheochromocytoma (PHEO). Mutations of VHL gene located in 3p25 may impair the function of the VHL protein and lead to the disease. It's unclear why obvious phenotype varieties exist among VHL patients. Here we aimed to ascertain whether the mutation types and locations affect the phenotype.

Methods

We enrolled 577 Chinese VHL patients from 211 families and divided them into three groups and six subgroups according to their mutation types and locations. Cox survival analysis and Kaplan-Meier analysis were used to compare intergroup age-related tumor risks.

Results

Patients with nonsense or frameshift mutations that were located before residues 117 of VHL protein (NoF1 subgroup) hold lower age-related risks of VHL associated tumors (HR = 0.638, 95%CI 0.461-0.883, p = 0.007), CHB (HR = 0.596, 95%CI 0.409-0.868, p = 0.007) or PCT (HR = 0.595, 95%CI 0.368-0.961, p = 0.034) than patients whose mutations were located after residues 117 (NoF2 subgroup). Patients in NoF1 subgroup still had lower age-related risks of CHB (HR = 0.652, 95%CI 0.476-0.893, p = 0.008) and PCT (HR = 0.605, 95%CI 0.398-0.918, p = 0.018) compared with those in combined NoF2 subgroup and other truncating mutation patients. NoF1 subgroup correspondingly had a longer estimated median lifespan (64 vs. 55 year, p = 0.037) than NoF2 subgroup. Among patients with missense mutations of VHL, only a small minority (23 of 286 missense mutations carriers) carried mutations involving neither HIF-α binding region nor elongin C binding region, who were grouped in MO subgroup. MO subgroup seemed to have a higher age-related risk of PHEO. In the whole cohort (n = 577), PHEO was an independent protective factor for CHB (p = 0.001) and survival (p = 0.005). RA and CHB failed to predict the age-related risk of each other.

Conclusion

The mutation types and locations of VHL gene are associated with phenotypes. Genetic counselors could predict phenotypes more accurately based on more detailed genotype-phenotype correlations. Further genotype-phenotype studies should focus on the prediction of tumor recurrence, progression, and metastasis. The deep molecular mechanism of genotype-phenotype correlation is worth further exploring.

Retinal haemangioblastomas in von Hippel-Lindau germline mutation carriers: progression, complications and treatment outcome

PURPOSE

Evaluation of phenotype and treatment outcome of retinal haemangioblastomas (RH) in von Hippel-Lindau (VHL) disease and correlation of these features with the genotype of VHL germline mutation carriers.

METHODS

Retrospective analysis of a longitudinal cohort of 21 VHL germline mutation carriers and RH. Clinical and genetic data were obtained to analyse the correlation of genotype with phenotype and treatment outcomes.

RESULTS

All patients were categorized in two genotypic categories: missense mutations (MM) and truncating mutations (TM). Mean follow-up duration was 16.3 years and did not differ significantly between mutation groups (p = 0.383). Missense mutations (MM) carriers (n = 6) developed more progression-related complications compared to TM carriers (n = 15) (p = 0.046). Vitreoretinal surgery was more often applied in MM carriers (p = 0.036). Moderate (visual acuity (VA)20/80 to 20/200) to severe (VA < 20/200) visual impairment was observed in 53.3% of the eyes of MM carriers and 28.1% of the eyes of TM carriers at last recorded visit.

CONCLUSION

Missense mutations in VHL patients seem to have a higher prevalence of progression-related complications. Missense mutations (MM) carriers required therefore more often vitreoretinal surgical treatment with a worse treatment outcome. Genetic analysis may play a role in determining a pro-active treatment strategy and prognosis for RH.

Insights into retinal hemangioblastoma using ultra widefield imaging

Purpose:

Retinal hemangioblastomas (RHs) are characteristic of von Hippel-Lindau (VHL) disease. Early diagnosis of retinal lesions may aid in systemic diagnosis. Early identification of VHL is life-saving and also prevents vision loss. Fundus fluorescein angiography (FFA) is a useful tool in the diagnosis and management of RHs. The aim of this study is to report FFA features of RH using ultra-widefield (UWF) imaging.

Methods:

A retrospective cross-sectional study of consecutive patients of RH who underwent UWF FFA at a tertiary eye care center. Images were analyzed and assessed by authors. The main outcome measures were (a) the number and size of RH in each eye and (b) vascular characteristics of the retina. UWF-FFA characteristics in each eye were tabulated. The number of clock hours involved by these characteristics and their correlation with the number and size of RH were analyzed.

Results:

The study evaluated 24 eyes of 13 patients. The mean age was 28.4 years. The median number of RHs in an eye was 3.5 (range 1–16), and the size of RHs varied from 0.1 to 4 disc diameters. Novel UWF-FFA findings noted in this study were the presence of abnormal capillary network in 22 of 24 eyes (91.7%), capillary leakage in 15 of 24 eyes (62.5%), and capillary telangiectasia in 7 of 24 eyes (29.2%). In addition, feeder arterioles and venules showed bulbous projections in 8 of 24 eyes (33.3%).

Conclusion:

The UWF-FFA characteristics of RH, which have not been described before, were identified. These add to our understanding of the pathogenesis of the disease and may pave the way for future therapeutic targets.

Phenotypic delineation of the retinal arterial macroaneurysms with supravalvular pulmonic stenosis syndrome

Retinal arterial macroaneurysms with supravalvular pulmonic stenosis (RAMSVPS), also known as Familial Retinal Arterial Macroaneurysms (FRAM) syndrome, is a very rare multisystem disorder. Here, we present a case series comprising ophthalmologic and systemic evaluation of patients homozygous for RAMSVPS syndrome causative IGFBP7 variant. New clinical details on 22 previously published and 8 previously unpublished patients are described. Age at first presentation ranged from 1 to 34 years. The classical feature of macroaneurysms and vascular beading involving the retinal arteries was universal. Follow up extending up to 14 years after initial diagnosis revealed recurrent episodes of bleeding and leakage from macroaneurysms in 55% and 59% of patients, respectively. The majority of patients who underwent echocardiography (18/23) showed evidence of heart involvement, most characteristically pulmonary (valvular or supravalvular) stenosis, often requiring surgical correction (12/18). Four patients died in the course of the study from complications of pulmonary stenosis, cerebral hemorrhage, and cardiac complications. Liver involvement (usually cirrhosis) was observed in eight patients. Cerebral vascular involvement was observed in one patient, and stroke was observed in two. We conclude that RAMSVPS is a recognizable syndrome characterized by a high burden of ocular and systemic morbidity, and risk of premature death. Recommendations are proposed for early detection and management of these complications.

Retinal capillary hemangioblastoma and hemiretinal vein occlusion in a patient with primary congenital glaucoma: A case report

The presence of retinal capillary hemangioblastoma and cerebellar hemangioblastoma in the context of Von Hippel-Lindau syndrome (VHL) is not characteristically associated with other ophthalmologic conditions. Here, we report the case of a 22-yearold female with a history of bilateral primary congenital glaucoma who presented with a right juxtapapillary retinal capillary hemangioblastoma and an old hemiretinal vein occlusion in which the retinal capillary hemangioblastoma was likely the contributing factor. Her systemic work up was positive for VHL syndrome and revealed the presence of a fatal large brainstem hemangioblastoma. To our knowledge, the association of VHL and congenital glaucoma and/or retinal venous occlusion has not been reported.

Downregulation of miR-21 inhibits the malignant phenotype of pancreatic cancer cells by targeting VHL

Background

MicroRNA (miR)-21 is overexpressed in numerous types of malignancy and participates in the development of cancer. However, the basic mechanism of the influence of miR-21 on the malignant phenotype of pancreatic cancer remains unclear.

Purpose

The present study aimed to investigate the role of miR-21 in pancreatic cancer development and explore its molecular mechanism.

Patients and methods

The tissue samples were collected at the Second Hospital of Tianjin Medical University (Tianjin, China) between January 2013 and December 2015. The expression of VHL in tissue samples was evaluated by IHC staining. The expression of miR-21 was measured by quantitative real-time polymerase chain reaction (qRT-PCR). MiR-21 target gene was detected by real-time PCR, Western blot and the luciferase reporter assay. Cell viability, cell proliferation, cell migration and invasion were evaluated by the MTT assays, the colony formation assays and the transwell assays. The nude mouse tumor xenograft model was performed to detect the effect of miR-21 on tumor growth in vivo.

Results

Von Hippel-Lindau tumor suppressor (VHL) was downregulated in pancreatic cancer tissues compared with pancreatic non-tumor tissues. VHL was identified as a novel direct target of miR-21, by which it is negatively regulated. In PANC-1 cells, inhibition of miR-21 and upregulation of VHL significantly suppressed cell proliferation, migration and invasion. Knockdown of miR-21 inhibited the hypoxia-inducible factor (HIF)-1α/vascular endothelial growth factor (VEGF) pathway, while inhibiting the expression of matrix metallopeptidase (MMP)-2 and MMP-9. Silencing of miR-21 inhibited tumor growth in vivo.

Conclusion

Knockdown miR-21 increased the expression of VHL, and thus modulated the HIF-1α/VEGF pathway and the expression of MMP-2 and MMP-9, which led to the inhibition of the proliferation, migration and invasion of pancreatic cancer cells. All of these results suggest that the miR-21/VHL interaction may be a novel potential target for pancreatic cancer prevention and therapy.

The β2-adrenergic receptor antagonist ICI-118,551 blocks the constitutively activated HIF signalling in hemangioblastomas from von Hippel-Lindau disease

One of the major consequences of the lack of a functional VHL protein in von Hippel-Lindau disease, a rare cancer, is the constitutive activation of the HIF pathway. This activation ends up in the generation of Central Nervous System (CNS) Hemangioblastomas among other tumours along the lifespan of the patient. Nowadays, only surgery has been proven efficient as therapy since the systemic attempts have failed. Propranolol, a non-specific β1-and β2-adrenergic receptor antagonist, was recently designated as the first therapeutic (orphan) drug for VHL disease. Nevertheless, its β1 affinity provokes the decrease in blood pressure, being not recommended for low or regular blood pressure VHL patients. In order to overcome the β1-drawback, the properties of a high specific β2-adrenergic receptor blocker named ICI-118,551 have been studied. ICI-118,551 was able to decrease Hemangioblastomas cell viability in a specific manner, by triggering apoptosis. Moreover, ICI-118,551 also impaired the nuclear internalization of HIF-1α in Hemangioblastomas and hypoxic primary endothelial cells, reducing significantly the activation of HIF-target genes and halting the tumour-related angiogenic processes. In this work, we demonstrate the therapeutical properties of ICI-118,551 in VHL-derived CNS-Hemangioblastoma primary cultures, becoming a promising drug for VHL disease and other HIF-related diseases.

Optimization of Next-Generation Sequencing Technologies for von Hippel Lindau (VHL) Mosaic Mutation Detection and Development of Confirmation Methods

Von Hippel-Lindau disease (VHL) is a monogenic disorder characterized by the development of tumors affecting the central nervous system, kidney, pancreas, or adrenal glands, and due to germline mutations in the VHL tumor suppressor gene. About 5% of patients with a typical VHL phenotype have no mutation detected by conventional techniques, so a postzygotic VHL mosaicism can be suspected. The aim of this study was therefore to implement a next-generation sequencing (NGS) strategy for VHL mosaic mutation detection, including an optimization of the original Personal Genome Machine design by enrichment with oligonucleotides corresponding to amplicons with insufficient depth of coverage. Two complementary strategies were developed for the confirmation of mosaic mutations identified by NGS, SNaPshot for variants present at an allelic ratio greater than 5%, and droplet digital PCR for allelic ratio above 1%. VHL mutant plasmids were generated to assess VHL mosaic mutation detection in different exons and to set up an internal quality control that could be included in each run or regularly to validate the assay. This strategy was applied to 47 patients with a suggestive or clinical VHL disease, and mosaic mutations were identified in 8.5% of patients. In conclusion, NGS technologies combined with SNaPshot or droplet digital PCR allow the detection and confirmation of mosaic mutations in a clinical laboratory setting.

Vasculogenesis and angiogenesis initiation under normoxic conditions through Wnt/β-catenin pathway in gliomas

The canonical Wnt/β-catenin pathway is up-regulated in gliomas and involved in proliferation, invasion, apoptosis, vasculogenesis and angiogenesis. Nuclear β-catenin accumulation correlates with malignancy. Hypoxia activates hypoxia-inducible factor (HIF)-1α by inhibiting HIF-1α prolyl hydroxylation, which promotes glycolytic energy metabolism, vasculogenesis and angiogenesis, whereas HIF-1α is degraded by the HIF prolyl hydroxylase under normoxic conditions. We focus this review on the links between the activated Wnt/β-catenin pathway and the mechanisms underlying vasculogenesis and angiogenesis through HIF-1α under normoxic conditions in gliomas. Wnt-induced epidermal growth factor receptor/phosphatidylinositol 3-kinase (PI3K)/Akt signaling, Wnt-induced signal transducers and activators of transcription 3 (STAT3) signaling, and Wnt/β-catenin target gene transduction (c-Myc) can activate HIF-1α in a hypoxia-independent manner. The PI3K/Akt/mammalian target of rapamycin pathway activates HIF-1α through eukaryotic translation initiation factor 4E-binding protein 1 and STAT3. The β-catenin/T-cell factor 4 complex directly binds to STAT3 and activates HIF-1α, which up-regulates the Wnt/β-catenin target genes cyclin D1 and c-Myc in a positive feedback loop. Phosphorylated STAT3 by interleukin-6 or leukemia inhibitory factor activates HIF-1α even under normoxic conditions. The activation of the Wnt/β-catenin pathway induces, via the Wnt target genes c-Myc and cyclin D1 or via HIF-1α, gene transactivation encoding aerobic glycolysis enzymes, such as glucose transporter, hexokinase 2, pyruvate kinase M2, pyruvate dehydrogenase kinase 1 and lactate dehydrogenase-A, leading to lactate production, as the primary alternative of ATP, at all oxygen levels, even in normoxic conditions. Lactate released by glioma cells via the monocarboxylate lactate transporter-1 up-regulated by HIF-1α and lactate anion activates HIF-1α in normoxic endothelial cells by inhibiting HIF-1α prolyl hydroxylation and preventing HIF labeling by the von Hippel-Lindau protein. Increased lactate with acid environment and HIF-1α overexpression induce the vascular endothelial growth factor (VEGF) pathway of vasculogenesis and angiogenesis under normoxic conditions. Hypoxia and acidic pH have no synergistic effect on VEGF transcription.

VHL-Associated Optic Nerve Hemangioblastoma Treated with Stereotactic Radiosurgery

Central nervous system hemangioblastomas are generally restricted to the cerebellum, spinal cord, and brainstem. Supratentorial hemangioblastomas are uncommon, and optic nerve hemangioblastomas are extremely rare, with fewer than 25 reports including this case. In this report, we present the case of a 36-year-old woman with von Hippel–Lindau (VHL) disease who presented with progressive diminution of vision in the left eye due to a retrobulbar optic nerve hemangioblastoma. The patient had a history of cerebellar/spinal hemangioblastomas and pancreatic cysts, and her father and brother were patients with VHL disease. Gadolinium-enhanced magnetic resonance imaging showed intraorbital retrobulbar–enhanced mass on the left optic nerve. The optic nerve hemangioblastoma was treated with fractionated stereotactic radiosurgery using Novalis. Eighteen months after the stereotactic radiosurgery, the tumor volume decreased although the patient lost vision. This report presents an extremely rare case of optic nerve hemangioblastoma, which is the first case treated with stereotactic radiosurgery.

Extraneuraxial Hemangioblastoma: Clinicopathologic Features and Review of the Literature

Extraneuraxial hemangioblastoma occurs in nervous paraneuraxial structures, somatic tissues, and visceral organs, as part of von Hippel-Lindau disease (VHLD) or in sporadic cases. The VHL gene plausibly plays a key role in the initiation and tumorigenesis of both central nervous system and extraneuraxial hemangioblastoma, therefore, the underlying molecular and genetic mechanisms of the tumor growth are initially reviewed. The clinical criteria for the diagnosis of VHLD are summarized, with emphasis on the distinction of sporadic hemangioblastoma from the form fruste of VHLD (eg, hemangioblastoma-only VHLD). The world literature on the topic of extraneuraxial hemangioblastomas has been comprehensively reviewed with ∼200 cases reported to date: up to 140 paraneuraxial, mostly of proximal spinal nerve roots, and 65 peripheral, 15 of soft tissue, 6 peripheral nerve, 5 bone, and 39 of internal viscera, including 26 renal and 13 nonrenal. A handful of possible yet uncertain cases from older literature are not included in this review. The clinicopathologic features of extraneuraxial hemangioblastoma are selectively presented by anatomic site of origin, and the differential diagnosis is emphasized in these subsets. Reference is made also to 10 of the authors' personal cases of extraneuraxial hemangioblastomas, which include 4 paraneuraxial and 6 peripheral (2 soft tissue hemangioblastoma and 4 renal).

Deletion of the von Hippel-Lindau Gene in Hemangioblasts Causes Hemangioblastoma-like Lesions in Murine Retina

von Hippel-Lindau (VHL) disease is an autosomal-dominant tumor predisposition syndrome characterized by the development of highly vascularized tumors and cysts. LOH of the VHL gene results in aberrant upregulation of hypoxia-inducible factors (HIF) and has been associated with tumor formation. Hemangioblastomas of the central nervous system and retina represent the most prevalent VHL-associated tumors, but no VHL animal model has reproduced retinal capillary hemangioblastomas (RCH), the hallmark lesion of ocular VHL. Here we report our work in developing a murine model of VHL-associated RCH by conditionally inactivating Vhl in a hemangioblast population using a Scl-Cre-ERT2 transgenic mouse line. In transgenic mice carrying the conditional allele and the Scl-Cre-ERT2 allele, 64% exhibited various retinal vascular anomalies following tamoxifen induction. Affected Vhl-mutant mice demonstrated retinal vascular lesions associated with prominent vasculature, anomalous capillary networks, hemorrhage, exudates, and localized fibrosis. Histologic analyses showed RCH-like lesions characterized by tortuous, dilated vasculature surrounded by "tumorlet" cell cluster and isolated foamy stromal cells, which are typically associated with RCH. Fluorescein angiography suggested increased vascular permeability of the irregular retinal vasculature and hemangioblastoma-like lesions. Vhl deletion was detected in "tumorlet" cells via microdissection. Our findings provide a phenotypic recapitulation of VHL-associated RCH in a murine model that may be useful to study RCH pathogenesis and therapeutics aimed at treating ocular VHL.Significance: This study describes a model that phenotypically recapitulates a form of retinal pathogenesis that is driven by genetic loss of the VHL tumor suppressor, providing a useful tool for its study and therapeutic intervention. Cancer Res; 78(5); 1266-74. ©2018 AACR.

Update on wide- and ultra-widefield retinal imaging

The peripheral retina is the site of pathology in many ocular diseases and ultra-widefield (UWF) imaging is one of the new technologies available to ophthalmologists to manage some of these diseases. Currently, there are several imaging systems used in practice for the purpose of diagnostic, monitoring disease progression or response to therapy, and telemedicine. These include modalities for both adults and pediatric patients. The current systems are capable of producing wide- and UWF color fundus photographs, fluorescein and indocyanine green angiograms, and autofluorescence images. Using this technology, important clinical observations have been made in diseases such as diabetic retinopathy, uveitides, retinal vascular occlusions and tumors, intraocular tumors, retinopathy of prematurity, and age-related macular degeneration. Widefield imaging offers excellent postoperative documentation of retinal detachment surgery. New applications will soon be available to integrate this technology into large volume routine clinical practice.

Neurological Management of Von Hippel-Lindau Disease

Von Hippel-Lindau disease is a genetic condition due to mutation of the Von Hippel-Lindau gene, which leads to an increased risk in the development of hemangioblastomas of the brain and spinal cord. The pathophysiology of disease and its clinical manifestations, as they pertain to the general neurologist, are discussed. Therapeutic management of central nervous system hemangioblastomas ranging from neurosurgical resection, radiation therapy, and systemic therapies is reviewed.

Infiltrating bone marrow mesenchymal stem cells (BM-MSCs) increase prostate cancer cell invasion via altering the CCL5/HIF2α/androgen receptor signals

Several infiltrating cells in the tumor microenvironment could influence the cancer progression via secreting various cytokines. Here, we found the CCL5 secreted from BM-MSCs suppressed androgen receptor (AR) signals via enhancing the expression of hypoxia inducible factor 2α (HIF2α) in prostate cancer (PCa) cells. Mechanism dissection revealed that the increased HIF2α might alter the AR-HSP90 interaction to suppress the AR transactivation, and inhibition of HIF2α reversed the BM-MSCs-increased PCa stem cell population and PCa cells invasion. Importantly, CCL5 could suppress the prolyl hydroxylases (PHDs) expression, which might then lead to suppress VHL-mediated HIF2α ubiquitination. Together, these results demonstrated that the CCL5 signals from infiltrating BM-MSC cells to HIF2α signals within PCa cells might play a key role to increase PCa stem cell population and PCa metastasis via altering the AR signals. Targeting this newly identified CCL5/HIF2α/AR axis signal axis may allow us to develop a novel way to suppress PCa metastasis.

Vitrectomy for Tractional Retinal Detachment with Twin Retinal Capillary Hemangiomas in a Patient with Von Hippel-Lindau Disease: A Case Report

Purpose

The purpose of this study was to report a case of Von Hippel-Lindau disease (VHL) with twin retinal capillary hemangiomas that was successfully treated by vitreous surgery for tractional retinal detachment following laser photocoagulation.

Case

A 44-year-old male presented at our university hospital after noticing decreased visual acuity in his right eye. The patient had previously undergone multiple operations for cerebellar, thoracic, and lumbar spine hemangioblastomas when he was approximately 19 years old. Upon initial examination, ocular findings revealed twin connected retinal capillary hemangiomas around the temporal upper area of the patient's right eye. The patient was subsequently diagnosed with VHL based on his medical history and current observations of the ocular fundus. Tractional retinal detachment had occurred as the result of the formation of proliferative membranes following laser photocoagulation. The patient underwent vitreous surgery to treat the tractional retinal detachment, resulting in a successful postoperative outcome.

Conclusion

The findings of this study show the possibility that proliferative changes and tractional retinal detachment can arise following photocoagulation for retinal capillary hemangiomas in patients with VHL.

An Update on the Ophthalmologic Features in the Phakomatoses

Neurofibromatosis type 1, tuberous sclerosis complex, and Von Hippel-Lindau disease, historically classified as the phakomatoses, are hereditary multisystem disorders characterized by the presence of hamartoma, which carry the risk of malignant transformation. The alteration of tumor suppressor genes seems to be at the basis of their pathophysiogenetic mechanism. Lisch and choroidal nodules in neurofibromatosis type 1, retinal astrocytomas in tuberous sclerosis complex, and retinal capillary hemangioma in Von Hippel-Lindau disease are the principal ophthalmic hamartomatous manifestations. The advent of novel imaging techniques such as near infrared reflectance and optical coherence tomography has provided unprecedented insight on the choroidal and retinal features of these diseases. These methods have improved early diagnosis and the ongoing surveillance in these conditions. Among an array of treatment modalities, antivascular endothelial growth factor therapy has been used in the management of retinal hamartomas but results have been varied. This review is an update on the pathophysiogenetic mechanisms, ophthalmic manifestations, and novel treatment strategies in the phakomatoses with emphasis on the role of imaging techniques.

ARNT2 Regulates Tumoral Growth in Oral Squamous Cell Carcinoma

Aryl hydrocarbon receptor nuclear translocator (ARNT) 2 is a transcriptional factor related to adaptive responses against cellular stress from a xenobiotic substance. Recent evidence indicates ARNT is involved in carcinogenesis and cancer progression; however, little is known about the relevance of ARNT2 in the behavior of oral squamous cell carcinoma (OSCC). In the current study, we evaluated the ARNT2 mRNA and protein expression levels in OSCC in vitro and in vivo and the clinical relationship between ARNT2 expression levels in primary OSCCs and their clinicopathologic status by quantitative reverse transcriptase-polymerase chain reaction, immunoblotting, and immunohistochemistry. Using ARNT2 overexpression models, we performed functional analyses to investigate the critical roles of ARNT2 in OSCC. ARNT2 mRNA and protein were down-regulated significantly (P < 0.05 for both comparisons) in nine OSCC-derived cells and primary OSCC (n=100 patients) compared with normal counterparts. In addition to the data from exogenous experiments that ARNT2-overexpressed cells showed decreased cellular proliferation, ARNT2-positive OSCC cases were correlated significantly (P < 0.05) with tumoral size. Since von Hippel-Lindau tumor suppressor, E3 ubiquitin protein ligase, a negative regulator of hypoxia-inducible factor (HIF1)-α, is a downstream molecule of ARNT2, we speculated that HIF1-α and its downstream molecules would have key functions in cellular growth. Consistent with our hypothesis, overexpressed ARNT2 cells showed down-regulation of HIF1-α, which causes hypofunctioning of glucose transporter 1, leading to decreased cellular growth. Our results proposed for the first time that the ARNT2 level is an indicator of cellular proliferation in OSCCs. Therefore, ARNT2 may be a potential therapeutic target against progression of OSCCs.

The Impact of Hypoxia and Mesenchymal Transition on Glioblastoma Pathogenesis and Cancer Stem Cells Regulation

Glioblastoma (GBM) is an aggressive primary brain tumor with potential for wide dissemination and resistance to standard treatments. Although GBM represents a single histopathologic diagnosis under current World Health Organization criteria, data from multiplatform molecular profiling efforts, including The Cancer Genome Atlas, indicate that multiple subgroups with distinct markers and biology exist. It remains unclear whether treatment resistance differs based on subgroup. Recent evidence suggests that hypoxia, or absence of normal tissue oxygenation, is important in generating tumor resistance through a signaling cascade driven by hypoxia-inducible factors and vascular endothelial growth factor. Hypoxia can result in isolation of tumor cells from therapeutic agents and activation of downstream tumor protective mechanisms. In addition, there are links between hypoxia and the phenomenon of mesenchymal transition in gliomas. Mesenchymal transformation in gliomas resembles at many levels the epithelial-mesenchymal transition that has been described in other solid tumors in which epithelial cells lose their epithelial characteristics and take on a more mesenchymal phenotype, but the mesenchymal transition in brain tumors is also distinct, perhaps related to the unique cell types and cellular organization in the brain and brain tumors. Cancer stem cells, which are specific cell populations involved in self-renewal, differentiation, and GBM pathophysiology, are also importantly regulated by hypoxia signaling pathways. In this review, we discuss the interplay of hypoxia and mesenchymal signaling in GBM including the key pathway regulators and downstream genes, the effect of these processes in regulation of the tumor microenvironment and cancer stem cells, and their role in treatment resistance.

Propranolol reduces viability and induces apoptosis in hemangioblastoma cells from von Hippel-Lindau patients

BACKGROUND

Von Hippel-Lindau (VHL) disease is a rare oncological disease with an incidence of 1:36,000, and is characterized by the growth of different types of tumors: hemangioblastomas in the central nervous system (CNS) and retina, renal carcinoma, pheochromocytomas, pancreatic serous cystadenoma, and endolymphatic sac tumors. These tumors do not express VHL protein (pVHL). pVHL ubiquitinates hypoxia inducible factor (HIF) protein for degradation by the proteasome; in the absence of VHL, HIF translocates to the nucleus to activate the expression of its target genes. Targeting VHL-derived tumors with drugs that have reduced side effects is urgent to avoid repeat CNS surgeries. Recent reports have shown that propranolol, a β-blocker used for the treatment of hypertension and other cardiac and neurological diseases, is the best option for infantile hemangioma (IH). Propranolol could be an efficient treatment to control hemangioblastoma growth in VHL disease because of its antiangiogenic effects demonstrated in IH and the hypothetical impact on HIF levels.

METHODS

HeLa 9X (HRE) hypoxia responsive element cell line and primary hemangioblastoma-derived cells were subjected to propranolol treatment and cell viability and apoptosis were evaluated. HIF1-α and Hif-2α expression after propranolol treatment was analyzed by western blotting. Quantitative PCR was performed to study the mRNA expression of HIF target genes. Vascular endothelial growth factor (VEGF) was measured in culture supernatants by immunoassay.

RESULTS

Propranolol downregulated HIF-dependent transcription in HeLa 9XHRE cells. Under hypoxic conditions, propranolol decreased the expression of HIF target genes in hemangioblastoma cells, which stopped proliferating and died following long-term treatment. These results suggests that propranolol treatment promoted reduced HIF protein expression and corresponding downregulation of HIF target genes, and inhibited cell proliferation in parallel with induction of cell death by apoptosis.

CONCLUSIONS

Our results suggest that propranolol could reduce the growth of HIF-dependent tumors and may thus be a promising treatment to delay surgery in VHL patients.

The genetic basis of intradural spinal tumors and its impact on clinical treatment

Genetic alterations in the cells of intradural spinal tumors can have a significant impact on the treatment options, counseling, and prognosis for patients. Although surgery is the primary therapy for most intradural tumors, radiochemothera-peutic modalities and targeted interventions play an ever-evolving role in treating aggressive cancers and in addressing cancer recurrence in long-term survivors. Recent studies have helped delineate specific genetic and molecular differences between intradural spinal tumors and their intracranial counterparts and have also identified significant variation in therapeutic effects on these tumors. This review discusses the genetic and molecular alterations in the most common intradural spinal tumors in both adult and pediatrie patients, including nerve sheath tumors (that is, neurofibroma and schwannoma), meningioma, ependymoma, astrocytoma (that is, low-grade glioma, anaplastic astrocytoma, and glioblastoma), hemangioblastoma, and medulloblastoma. It also examines the genetics of metastatic tumors to the spinal cord, arising either from the CNS or from systemic sources. Importantly, the impact of this knowledge on therapeutic options and its application to clinical practice are discussed.

pVHL Negatively Regulates Antiviral Signaling by Targeting MAVS for Proteasomal Degradation

The von Hippel-Lindau (VHL) gene is a well-defined tumor suppressor linked to human heredity cancer syndromes. As a component of the VHL-elongin B/C E3 ligase complex, pVHL performs its tumor function by targeting proteins for proteasomal degradation. It is largely unknown whether pVHL functions in antiviral immunity. In this article, we identify that pVHL negatively regulates innate antiviral immunity, which acts mainly by inducing degradation of mitochondrial antiviral-signaling protein (MAVS, also known as Cardif, IPS-1, or VISA). Overexpression of pVHL abrogated the cellular response to viral infection, whereas knockdown of pVHL exerted the opposite effect. pVHL targeted the K420 residue of MAVS to catalyze the formation of K48-linked polyubiquitin chains, leading to proteasomal degradation of MAVS. After viral infection, Mavs levels remained low in wild type zebrafish embryos but became much higher in vhl-deficient (vhl(-/-)) zebrafish embryos. Higher MAVS levels correlated with a greatly exaggerated antiviral response. In this work, we demonstrate that pVHL exhibits a previously unknown role in innate antiviral immunity.

The genetic classification of pancreatic neoplasia

Cancer is caused by the accumulation of inherited and/or acquired alterations in specific genes. The recent decline in the cost of DNA sequencing has allowed tumor sequencing to be conducted on a large scale, which, in turn, has led to an unprecedented understanding of the genetic events that drive neoplasia. This understanding, when integrated with meticulous histologic analyses and with clinical findings, has direct clinical implications. The recent sequencing of all of the major types of cystic and noncystic neoplasms of the pancreas has revealed opportunities for molecular diagnoses and for personalized treatment. This review summarizes the results from these recent studies focusing on the clinical relevance of genomic data.

Hemangioblastoma of the optic nerve producing bilateral optic tract edema in a patient with von Hippel-Lindau disease

BACKGROUND

The authors present a novel case of a hemangioblastoma of the optic nerve producing bilateral optic tract edema in a patient with von Hippel-Lindau disease (VHL). This is the only case in the literature documenting optic tract edema secondary to a hemangioblastoma of the optic nerve.

CASE DESCRIPTION

The patient was a 34-year-old female in whom this lesion was causing retro-orbital pain and proptosis. She had previously lost vision in the symptomatic eye secondary to a retinal hemangioblastoma. The optic nerve lesion was excised by sectioning the optic nerve both proximally and distally to the lesion. There were no complications and patient's symptoms resolved postoperatively. A follow-up magnetic resonance imaging (MRI) scan revealed complete excision of the mass and resolution of the optic tract edema.

CONCLUSION

Optic nerve hemangioblastomas in patients with VHL are rare, but are manageable with meticulous microneurosurgery and with appropriate patient expectations. This is the first known case of an optic nerve hemangioblastoma producing bilateral optic tract edema, which resolved after resection of the prechiasmal tumor. Hemangioblastoma should remain in the differential diagnosis of optic nerve tumors, especially in the setting of VHL.