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Intracellular proteins continuously turn over by degradation and synthesis in all organ tissues. Owing to its irreversible nature, protein degradation is a highly selective process to avoid irreparable breakdown of cellular constituents, thereby disrupting cellular stability, integrity and signalling. The majority of intracellular proteins are degraded by the ubiquitin-proteasome system (UPS), a multi-enzyme process that involves the covalent conjugation of ubiquitin to a substrate protein and its recognition and degradation by the core multicomponent proteolytic complex of the UPS, the proteasome. In addition to labelling misfolded, damaged, aggregation-prone and intact but unneeded proteins for proteasomal degradation, ubiquitylation regulates a multitude of cellular processes, such as transcription, translation, endocytosis, and receptor activity and subcellular localization. In addition, the proteasome generates peptides for antigen presentation in the immune system and for further degradation by peptidases to provide amino acids for protein biosynthesis and gluconeogenesis. Alterations of the UPS or of protein substrates that render them more or less susceptible to degradation are responsible for disorders associated with renal cell dysfunction. In this Review, we provide insight into the elegant and complex nature of UPS-mediated proteostasis and focus on its established and potential roles in renal cell physiology and pathophysiology.

The phakomatoses, encephalotrigeminal angiomatosis (ETA; Sturge-Weber Syndrome), neurofibromatosis type 1 (NF1 or von Recklinghausen disease), Von Hippel-Lindau (VHL) disease, tuberous sclerosis (TSC), oculodermal melanocytosis (ODM), and phakomatosis pigmentovascularis are a group of neurocutaneous disorders that have characteristic systemic and ocular manifestations. Through many different mechanisms, they may cause glaucomatous damage of the optic nerve and subsequent vision loss varying from mild to severe. Glaucoma commonly affects patients with ETA (43-72%), orbito-facial NF1 (23-50%), and ODM (10%). Rarely, it may present as neovascular glaucoma in VHL and TSC. In ETA, glaucoma typically occurs ipsilateral to the port-wine stain, which is caused by a mutation in the GNAQ gene. Specifically, mechanical malformation of the anterior chamber angle and elevated episcleral venous pressure has been implicated as causes of glaucoma in ETA. In NF1, which is caused by a mutation in the NF1 tumor suppressor gene, glaucoma commonly occurs ipsilateral to lid plexiform neurofibromas. Histological studies of eyes with NF1 have revealed direct anterior chamber infiltration by neurofibromas, secondary angle closure, fibrovascularization, and developmental angle abnormalities as mechanisms of glaucoma. Lastly, phakomatosis pigmentovascularis is a rare combination of ODM and port-wine stain. Affected patients are at very high risk of developing glaucoma. Despite the many different mechanisms of glaucomatous damage, management follows similar principles as that for congenital glaucoma and primary open angle glaucoma. First-line therapy is topical intraocular pressure-lowering eye drops. Surgical management, including goniotomy, trabeculotomy, trabeculectomy, and tube shunt placement may be required for more severe cases., (© 2018 Wiley Periodicals, Inc.)

A 45-year old woman who underwent several surgeries for tumors associated with von Hippel-Lindau disease (VHL) was referred to our hospital due to a pancreatic tumor and liver tumors. She was diagnosed with pancreatic neuroendocrine tumor (NET) with a Ki67 index of 40% based on the examination of a biopsy specimen of the liver tumors. She was treated with everolimus for 6 months and sunitinib for 6 weeks as first- and second-line therapies. She survived for 13 months. At autopsy the diagnosis of pancreatic neuroendocrine tumor (NET)-G3 was confirmed. We herein report an aggressive clinical course of VHL-related NET G3. The further accumulation of cases is required to reach a consensus on treatment for this disease.

Phakomatoses (phakoma = birthmark) are a group of diseases or syndromes that have hamartomas (tumorous malformations composed of tissues normally present at the location where they develop) of the skin, brain, and eye (oculoneurocutaneous syndromes).

The autosomal dominant von Hippel-Lindau disease (vHL) is associated with a lifelong risk of tumor development, especially retinal and CNS hemangioblastomas, pheochromocytoma, and renal cell carcinoma. Knowledge of paediatric vHL development is limited, and current surveillance guidelines are based on expert opinions. We aimed to describe the course of vHL development in children and adolescents, focusing on age at first manifestation, manifestation frequencies, and types. The prevalence of vHL diagnosis as well as manifestations in childhood were evaluated based on 99 patients, who had started surveillance before 18 years: 37 Danish patients from the national vHL research database and 62 international patients reported in 15 articles. Overall, 70% (69 of 99) developed manifestations before 18 years (median age at first manifestation: 12 years (range: 6-17 years)). Thirty per cent (30 of 99) had developed more than one manifestation type; the most frequent were retinal (34%) and CNS (30%) hemangioblastomas. Among the 37 Danish patients, 85% (97 of 116) of their tumors were asymptomatic. Vision outcome is significantly improved in hemangioblastomas that are treated while still asymptomatic. We agree with current guidelines that retinal surveillance be performed from birth. The patients had their first CNS hemangioblastomas at the median ages of 13-14 years (range: 6-17 years). Further, 11% (4 of 37) of the Danish patients had CNS surgery in their teenage years. Although the cohort is too small to make definite conclusions about specific initiation ages, regular CNS surveillance from vHL patients' teenage years seems clinically relevant., (© 2017 Wiley Periodicals, Inc.)

Rationale: Von Hippel-Lindau (VHL) disease is a rare inherited, autosomal-dominant syndrome caused by heterozygous germline mutations in the VHL gene. VHL patients are prone to develop benign and malignant tumors and cysts in multiple organ systems involving kidneys, pancreas and central nervous system (CNS). The varied and complex clinical manifestations and radiological findings of VHL are of interest., Patient Concerns: We report a 38-year-old woman with a ten-year history of VHL disease involving both pancreas and biliary system. To the best of our knowledge, direct involvement of the biliary system in VHL disease has never been reported., Diagnoses: The diagnosis was established via computed tomography scan and was confirmed by genetic testing., Interventions: The patient chose to receive conservative treatment and was followed up by magnetic resonance cholangiopancreatography and magnetic resonance imaging examination., Outcomes: Renal angiomas and cysts were found during follow-up and there were no evidence of malignant change of the pancreas and biliary system., Lessons: We described the first case of VHL-associated choledochal cysts and may present new visceral manifestations of VHL disease. Gastroenterologists should be aware of the clinical presentations of this rare disease for early detection of its life-threatening manifestations., Competing Interests: The authors have no conflicts of interest to disclose.

von Hippel-Lindau (VHL) disease is an inherited syndrome manifesting with benign and malignant tumors. Deficiency of carnitine palmitoyltransferase type II (CPT2) is a disorder of lipid metabolism that, in the muscle form, manifests with recurrent attacks of myalgias often associated with myoglobinuria. Rhabdomyolytic episodes may be complicated by life-threatening events, including acute renal failure (ARF). We report on a male patient who was tested, at 10 years of age, for VHL disease because of family history of VHL. He was diagnosed with VHL but without VHL-related manifestation at the time of diagnosis. During childhood, the patient was hospitalized several times for diffuse muscular pain, muscle weakness, and dark urine. These recurrent attacks of rhabdomyolysis were never accompanied by ARF. The patient was found to be homozygous for the mutation p.S113L of the CPT2 gene. To the best of our knowledge, this is the first report of the coexistence of VHL disease and CPT2 deficiency in the same individual. Based on findings from animal models, the case illustrates that mutations in the VHL gene might protect against renal damage caused by CPT2 gene mutations., Competing Interests: relevant to this article was not reported.

Purpose: Terson's syndrome is a condition where a preretinal hemorrhage forms as a result of increased intracranial pressure. The elevated intracranial pressure is thought to be transmitted through the veins and the optic nerve sheath to the optic disc and retina, causing the thin capillary walls to rupture. The authors present a unique case of Terson's syndrome in a patient who underwent recent surgical management for cerebellar hemangioblastomas related to von Hippel-Lindau disease., Case Report: A 17-year-old African American female patient with a history of von Hippel-Lindau disease presented with pain in her right eye. She had recently undergone surgery to remove cerebellar hemangioblastomas. Preliminary fundus imaging was performed, but before formal ophthalmic testing could be conducted, the patient seized and was taken directly to the emergency room. When the patient returned for a formal evaluation 3 weeks later, a new preretinal "boat-shaped" hemorrhage was now present. Additionally, reports from the emergency room suggested that she had bled into the cavity where the previous cerebellar resection had taken place. This hemorrhage likely led to an increase in intracranial pressure, causing a Terson's-like event., Conclusions: A Terson's event may be caused by high intracranial pressure secondary to the surgical removal of von Hippel-Lindau syndrome-associated cerebellar tumors and should be included as a possible complication of surgical management.

Purpose: To investigate spectrum of patients with Von Hippel-Lindau disease (VHL) that required pars plana vitrectomy and evaluate anatomical and functional outcomes of surgery., Methods: Twenty-three patients who underwent surgery for advanced VHL eye disease were assessed by genetic tests, diagnostic tests for systemic lesions, and clinical eye examination. The vitrectomized eyes were divided into two groups: with or without retinotomy (group R vs. NR). Functional and anatomical outcome was analyzed and compared between the groups., Results: All patients had central nervous system hemangioblastomas and 57% had other systemic tumors. Point germline mutations, large partial deletions, and complete vhl gene deletions were found in 64%, 27%, and 9% of patients, accordingly. Destruction of hemangioblastomas by retinotomy, laser, or cryotherapy and anatomical attachment of the retina were achieved in all eyes. Preoperative mean distance best-corrected visual acuity was logarithm of the minimum angle of resolution 2.66 (20/9,140) in group R and 1.76 (20/1,150) in group NR (P < 0.05). At 6 months postoperatively, distance best-corrected visual acuity improved in 20 eyes (83%). After over 24 months postoperatively, distance best-corrected visual acuity remained better than preoperatively in 36% in the R group and in 70% in the NR group of eyes. During 24 months postoperatively in 17 eyes, new retinal capillary hemangiomas developed. The mean number of new retinal capillary hemangiomas per eye was higher in group R than in group NR (3.14 vs. 0.70; P < 0.01). In group R, number of new retinal capillary hemangioblastoma was higher in retinal segments where retinotomy was performed (n = 29) than in other areas (n = 13) (P < 0.01)., Conclusion: Advanced VHL eye disease correlates with occurrence of central nervous system and systemic lesions. Spectrum of vhl gene mutation in the patients corresponds to that of the general VHL population. Pars plana vitrectomy in advanced VHL eye disease can improve or preserve visual function, but postoperative progression of ocular VHL disease can be accelerated in cases where retinotomy is performed.

Patients with a germline mutation in von Hippel-Lindau (VHL) develop renal cell cancers and hypervascular tumors of the brain, adrenal glands, and pancreas as well as erythrocytosis. These phenotypes are driven by aberrant expression of HIF2α, which induces expression of genes involved in cell proliferation, angiogenesis, and red blood cell production. Currently, there are no effective treatments available for VHL disease. Here, using an animal model of VHL, we report a marked improvement of VHL-associated phenotypes following treatment with HIF2α inhibitors. Inactivation of vhl in zebrafish led to constitutive activation of HIF2α orthologs and modeled several aspects of the human disease, including erythrocytosis, pathologic angiogenesis in the brain and retina, and aberrant kidney and liver proliferation. Treatment of vhl(-/-) mutant embryos with HIF2α-specific inhibitors downregulated Hif target gene expression in a dose-dependent manner, improved abnormal hematopoiesis, and substantially suppressed erythrocytosis and angiogenic sprouting. Moreover, pharmacologic inhibition of HIF2α reversed the compromised cardiac contractility of vhl(-/-) embryos and partially rescued early lethality. This study demonstrates that small-molecule targeting of HIF2α improves VHL-related phenotypes in a vertebrate animal model and supports further exploration of this strategy for treating VHL disease.

Purpose of Review: Cystic kidney diseases are common renal disorders characterized by the formation of fluid-filled epithelial cysts in the kidneys. The progressive growth and expansion of the renal cysts replace existing renal tissue within the renal parenchyma, leading to reduced renal function. While several genes have been identified in association with inherited causes of cystic kidney disease, the molecular mechanisms that regulate these genes in the context of post-transcriptional regulation are still poorly understood. There is increasing evidence that microRNA (miRNA) dysregulation is associated with the pathogenesis of cystic kidney disease., Recent Findings: In this review, recent studies that implicate dysregulation of miRNA expression in cystogenesis will be discussed. The relationship of specific miRNAs, such as the miR-17∼92 cluster and cystic kidney disease, miR-92a and von Hippel-Lindau syndrome, and alterations in LIN28-LET7 expression in Wilms tumor will be explored., Summary: At present, there are no specific treatments available for patients with cystic kidney disease. Understanding and identifying specific miRNAs involved in the pathogenesis of these disorders may have the potential to lead to the development of novel therapies and biomarkers.

Von Hippel-Lindau disease is a rare genetic disorder which gives rise to a range of tumours including central nervous system haemangioblastomas. We report a case of caesarean section in a patient with symptomatic cerebellar haemangioblastomas associated with von Hippel-Lindau disease. An intracranial pressure monitor was inserted before surgery, which enabled intracranial pressure to be monitored throughout. The anaesthetic implications of von Hippel-Lindau disease are discussed and clinical options explored., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Hemangioblastoma is a rare benign neoplasm, accounting for less than 2% of all primitive brain tumors. It may arise sporadically in a solitary form, or associated with Von Hippel-Lindau (VHL) disease with multiple tumors. Surgery is the mainstay treatment, but management is challenging in case of recurrent and/or multiple tumors. VHL protein is defective in both forms of hemangioblastoma, leading to the accumulation of hypoxia-inducible factor, stimulating angiogenesis via VEGF and PDGF mainly. Here, we report a 37-year-old woman's case with recurrent and rapidly progressive VHL-associated hemangioblastomas, causing severe disability. She was treated 24 months with pazopanib, a multityrosine kinase inhibitor (TKI) targeting VEGF and PDGF-β pathways. Despite moderate radiological changes, progressive improvement in her clinical condition persisting over 3 years was observed. Inhibiting angiogenesis is a therapeutic option that may improve the quality of life and the autonomy of VHL patients disabled with multiple hemangioblastomas.

Purpose: To investigate genotype-phenotype correlation and to analyze functional and structural changes in the retina of patients with von Hippel-Lindau (VHL) disease., Methods: Thirteen patients from four families (A, B, C and D) with known VHL disease and known mutations in the VHL gene were examined. All patients underwent clinical examination and optical coherence tomography (OCT). Full-field electroretinography (full-field ERG) was performed in twelve patients., Results: Family A, with deletion of exon 3 in the VHL gene, and family B, with the missense mutation p.R79P, exhibited type 1 VHL characterized by the absence of pheochromocytoma and a high incidence of central nervous system hemangioblastomas. One member of family B exhibited Goldenhar syndrome. A novel missense mutation (p.L198P) was identified in the VHL gene in the patient from family C. This p.L198P mutation caused a phenotype with early onset of a neuroendocrine tumor of the pancreas, bilateral pheochromocytomas, and optic nerve hemangioblastoma. Full-field ERG showed significantly prolonged implicit times of the b-wave and maximal combined a-wave in VHL patients, compared to controls. Examination of the retinal structure in all patients with VHL, using OCT, showed a significant decrease in retinal thickness in VHL patients without ocular hemangioblastomas, compared to controls., Conclusions: Our findings support previously established genotype-phenotype correlations. However, we here describe an unusual phenotype with a novel missense mutation, p.L198P, and report the finding that VHL disease can be associated with Goldenhar syndrome. Electrophysiological and structural findings suggest that VHL disease is a progressive, neurodegenerative disease of the retina.

von Hippel-Lindau (VHL) disease is an autosomal-dominant familial cancer syndrome associated with mutations of the VHL tumor suppressor gene (3p25-26). Its estimated incidence ranges from 1 in 36,000 to 1 in 53,000 with a penetrance of up to 95% by age 60. Genotype-phenotype correlation divides VHL into two broad clinical subtypes. Type 1 VHL is predominantly associated with large deletion or truncation mutations which result in an encoded protein with very little or no activity. It is associated with retinal and CNS hemangioblastoma and renal cell carcinoma but not pheochromocytoma. Type 2 is usually associated with missense mutations encoding a protein with limited activity and includes pheochromocytoma. It is further classified into three other subtypes (2A, 2B, 2C) based on the presence of hemangioblastoma and renal cell carcinoma. Visceral cysts in the kidney, pancreas and epididymis, nonfunctioning pancreatic neuroendocrine tumors which often show distinctive clear cell cytology, endolymphatic sac tumors and head and neck paragangliomas are well recognized but less common presenting features. Surveillance of carriers can reduce the burden of disease and is best performed in specialist referral centers with due consideration given to both the complex molecular pathogenesis and psychosocial aspects of the disease., (Copyright © 2013 S. Karger AG, Basel.)

Dilated cardiomyopathy resulting from pheochromocytoma-mediated catecholamine excess poses a unique challenge to heart failure management. Although early screening of patients with familial neoplastic syndromes at risk for pheochromocytoma may facilitate early resection, the resultant manifestations of prolonged catecholamine excess among patients with undiagnosed pheochromocytoma may lead to myocardial fibrosis with both systolic and diastolic dysfunction. Furthermore, the hemodynamic effects of catecholamine excess exacerbate the risks of perioperative hemodynamic instability in the setting of such myocardial depression. This report describes an approach to the perioperative care of a child who had pheochromocytoma and catecholamine-induced cardiomyopathy with ventricular dysfunction refractory to medical management.

Objective: Characterization of the structural and functional progression of ocular von Hippel-Lindau (VHL) disease and analysis of patient factors influencing disease progression., Design: Retrospective analysis of a case series from a longitudinal, observational study., Participants: Two hundred forty-nine participants with clinically defined systemic VHL disease and more than 2 years of ophthalmic follow-up., Methods: Standardized scoring of ocular phenotype and systemic characteristics was performed at each study visit and was analyzed longitudinally to determine progression of ocular VHL disease., Main Outcome Measures: Measures evaluated include: visual acuity, features of ocular VHL disease (presence, location, number, and extent of retinal capillary hemangioblastomas [RCHs]), germline mutation in the VHL gene, demographics (age, gender, age at onset of ocular disease), and patient characteristics (smoking status, body mass index)., Results: Most participants demonstrated relative anatomic and functional stability in ocular VHL disease status over a mean follow-up of 8.2 ± 4.0 years. Approximately three quarters (73%) of participants without ocular VHL disease at baseline remained disease free at the end of follow-up. Among eyes with ocular VHL disease at baseline, 88% did not demonstrate RCHs in a new retinal location, 70% remained stable in RCH number, and 79% remained stable in the extent of RCH involvement. Mean visual acuity for all study eyes (n = 498) decreased by 5.1 ± 0.6 letters across follow-up, with 16.1% of study eyes decreasing by more than 10 letters in visual acuity. Among eyes affected at baseline, greater vision loss was associated with the presence of juxtapapillary RCHs, development of RCH in a new location, and increase in peripheral RCH number and extent. Younger baseline age, younger age at onset of ocular VHL disease, involvement of the fellow eye with ocular VHL disease, and missense or protein-truncating germline mutations were associated significantly with increased anatomic involvement and functional deterioration., Conclusions: Patients with ocular VHL disease maintain relative anatomic and functional stability, with only a minority demonstrating marked anatomic progression and vision loss. Systemic and ocular risk factors for anatomic progression and vision loss can help practitioners identify patients with a higher risk profile for counseling, closer follow-up, and proactive treatment., Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article., (Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

The von Hippel-Lindau tumor suppressor gene (VHL) is best known as an E3 ubiquitin ligase that negatively regulates the hypoxia inducible factor (HIF). VHL mutations are the genetic defects underlying several human diseases including polycythemia, familial VHL tumor syndrome and sporadic renal cell carcinoma. VHL mutations can lead to cell-autonomous phenotypes in the tumor cells. However, non-tumor cell-autonomous functions of VHL have also been noted. VHL tumor-derived cytokines can promote inflammation and induce mobilization of endothelial progenitor cells. Up-regulation of HIF caused by VHL loss-of-function mutants, including heterozygotes, has been shown to increase the activities of hematopoietic stem cells, endothelial cells and myeloid cells. As such, systemic functions of VHL likely play important roles in the development of VHL disease., (Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)

Context: Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome in which patients are at risk of developing multiple tumors in different organs. 6-L-¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-FDOPA) positron emission tomography (PET) is a relatively new metabolic imaging tracer proposed for the use of localizing sites of neuroendocrine tumors. There are limited data on the clinical utility of using ¹⁸F-FDOPA PET for identifying neuroendocrine tumors in a high-risk population such as VHL., Objective: The aim of this prospective study was to evaluate the clinical utility of ¹⁸F-FDOPA PET in patients with VHL-related tumors., Design: Radiological findings were prospectively collected from four imaging modalities: computed tomography, magnetic resonance imaging (MRI), ¹⁸F-fluorodeoxyglucose PET, and ¹⁸F-FDOPA PET. ¹⁸F-FDOPA PET findings were compared with those from other imaging modalities, as well as with clinical and laboratory data, and pathology findings if patients underwent an operation., Results: In 52 patients with VHL, 390 lesions were identified by computed tomography (n = 139), MRI (n = 117), ¹⁸F-fluorodeoxyglucose PET (n = 94), and ¹⁸F-FDOPA PET (n = 40). ¹⁸F-FDOPA PET identified 20 pancreatic and 20 extrapancreatic tumors, including lesions in the adrenal gland (n = 11), kidney (n = 3), liver (n = 4), lung (n = 1), and cervical paraganglioma (n = 1). These tumor sites were not seen by conventional imaging studies in 9.6% of patients and 4.4% of lesions. Seven of eight patients who had an ¹⁸F-FDOPA PET-positive lesion underwent resection, and pathology showed a neuroendocrine tumor. Four of 10 patients with positive adrenal uptake had elevated catecholamine levels, and six of 10 patients had a discrete mass on axial imaging., Conclusions: ¹⁸F-FDOPA PET is a useful complementary imaging study to detect neuroendocrine tumors in patients with VHL undergoing surveillance, especially in those suspected to have adrenal pheochromocytoma or unusual ectopic locations.

Purpose: : Up to 16% of patients with the hereditary von Hippel-Lindau disease develop endolymphatic sac tumors of the inner ear. Early diagnosis and treatment of endolymphatic sac tumors can prevent audiovestibular morbidity, but optimal endolymphatic sac tumor surveillance strategy has yet to be determined. We aimed to evaluate endolymphatic sac tumor surveillance to determine the best surveillance strategy., Methods: : In a national prospective study, 40 VHL mutation carriers were interviewed about audiovestibular symptoms and had audiological examinations and magnetic resonance imaging of the inner ear. Further, we performed a meta-analysis including all reported endolymphatic sac tumor von Hippel-Lindau disease cases in the literature (N = 140 with 156 endolymphatic sac tumors)., Results: : In the prospective study, endolymphatic sac tumors were suspected based on audiovestibular symptoms, audiometry, and magnetic resonance imaging in 34%, 30%, and 12.5% of subjects, respectively. In total, more than 90% of radiologically diagnosed endolymphatic sac tumors were associated with abnormal audiometric findings. No endolymphatic sac tumor genotype-phenotype correlations were found., Conclusion: : We recommend annual audiometry as a first-line endolymphatic sac tumor screening tool, and in countries where periodic surveillance magnetic resonance imaging of the central nervous system is performed, specific images of the inner ear should be included. Audiometric abnormalities in patients with von Hippel-Lindau disease without magnetic resonance imaging-visible endolymphatic sac tumors could be due to microscopic endolymphatic sac tumors. Determination of audiometric endolymphatic sac tumor characteristics could further target screening and improve endolymphatic sac tumor diagnosis.

In many kidney diseases, the original insult primarily involves the glomerulus and may then pass onto the tubulointerstitium. Several hypotheses link glomerular disease to tubular injury; perhaps the foremost hypothesis involves chronic tubular hypoxia. The reported effects of hypoxia and consecutive stabilization of hypoxia-inducible factors (HIFs), however, are controversial. Hypoxia induces interstitial fibrosis but also has beneficial effects on renal disease progression when HIF is activated pharmacologically. To analyze the impact of HIF on tubulointerstitial disease development in primary glomerular disease, transgenic von Hippel Lindau (VHL)-knockout mice were generated and null expression was induced before the onset of autoimmune IgG-mediated anti-glomerular basement membrane glomerulonephritis (GN). Tubular VHL knockout and, thus, local HIF-α stabilization increased renal production of vascular endothelial growth factor, tumor growth factor-β(1), and platelet-derived growth factor-B, resulting in augmented formation of capillaries and interstitial matrix, and conversion of fibroblasts to myofibroblasts. Within the glomerular disease, VHL knockout reduced the glomerular damage and attenuated tubulointerstitial injury. Likewise, proteinuria, plasma urea concentration, and tubulointerstitial matrix were decreased in VHL knockout with GN. These findings shown that tubular HIF-α stabilization in glomerular disease is beneficial for disease outcome. In comparison with VHL knockout alone, GN is a much stronger activator of fibrosis such that stimuli other than hypoxia may be considered important for renal disease progression., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Background: Animal models are instrumental in understanding disease pathophysiology and mechanisms of therapy action and resistance in vivo., Objective: To establish and characterize a panel of mouse models of renal cell carcinoma (RCC) derived from patients undergoing radical nephrectomy., Design, Setting, and Participants: In vivo and in vitro animal experiments., Measurements: Tumor tissues obtained during surgery were implanted into the subcutaneous space of female BALB/c nude mice and serially passaged into new mice. Tumors were characterized by histology, short tandem repeat (STR) fingerprinting, von Hippel-Lindau (VHL) gene sequencing, and single nucleotide polymorphism (SNP) analysis. Tumor-bearing mice were treated with sunitinib or everolimus. Primary cell cultures were derived from patient tumors and transfected with a lentivirus carrying the luciferase gene. Four subcutaneous xenograft mouse models were developed, representing papillary type 1, papillary type 2, clear cell, and clear cell with sarcomatoid features RCC., Results and Limitations: RCC mouse models were established from four patients with distinct histologies of RCC. Tumor growth was dependent on histologic type, the size of the implanted tumor chip, and the passage number. Mouse tumors accurately represented their respective original patient tumors, as STR fingerprints were matching, histology was comparable, and SNP profiles and VHL mutation status were conserved with multiple passages. Bioluminescence imaging results were commensurate with subcutaneous xenograft growth patterns. Mice treated with sunitinib and everolimus exhibited an initial response, followed by a later stage of resistance to these agents, which mimics the clinical observations in patients with RCC., Conclusions: We developed four mouse xenograft models of RCC with clear-cell and papillary histologies, with stable histologic and molecular characteristics. These models can be used to understand the basic biology of RCC as well as response and resistance to therapy., (Copyright © 2010 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Von Hippel-Lindau disease is an inherited syndrome predisposing to a variety of benign and malignant neoplasms of the central nervous system and viscera that requires comprehensive screening and follow-up of individuals and their families. As such, it is important for the neurosurgeon to be aware of its clinical features and management issues. In this article we review the clinical aspects, management and surveillance of von Hippel-Lindau disease for neurosurgical practice., (Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.)

β-cells sense glucose and secrete appropriate amounts of insulin by coupling glucose uptake and glycolysis with quantitative ATP production via mitochondrial oxidative pathways. Therefore, oxidative phosphorylation is essential for normal β-cell function. Multiple cell types adapt to hypoxia by inducing a transcriptional programme coordinated by the transcription factor hypoxia-inducible factor (HIF). HIF activity is regulated by the von Hippel-Lindau (Vhl) protein, which targets the HIFα subunit for proteasomal degradation in the presence of oxygen. Several recent studies have shown that Vhl deletion in β-cells results in Hif1α activation, impaired glucose-stimulated insulin secretion (GSIS) and glucose intolerance. This was found to be because of alterations in β-cell gene expression inducing a switch from aerobic glucose metabolism to anaerobic glycolysis, thus disrupting the GSIS triggering pathway. Situations in which islets may become hypoxic are discussed, in particular islet transplantation which has been reported to cause islet hypoxia because of an inadequate blood supply post-transplant. Aside from this principal role for HIF in negatively regulating β-cell glucose sensing, other aspects of hypoxia signalling are discussed including β-cell differentiation, development and vascularization. In conclusion, recent studies clearly show that hypoxia response mechanisms can negatively impact on glucose sensing mechanisms in the β-cell and this has the potential to impair β-cell function in a number of physiological and clinical situations., (© 2010 Blackwell Publishing Ltd.)

Renal cystic diseases in adults are a heterogeneous group of disorders characterized by the presence of multiple cysts in the kidneys. These diseases may be categorized as hereditary, acquired, or developmental on the basis of their pathogenesis. Hereditary conditions include autosomal dominant polycystic kidney disease, medullary cystic kidney disease, von Hippel-Lindau disease, and tuberous sclerosis. Acquired conditions include cystic kidney disease, which develops in patients with end-stage renal disease. Developmental cystic diseases of the adult kidney include localized renal cystic disease, multicystic dysplastic kidney, and medullary sponge kidney. In recent years, many molecular and cellular mechanisms involved in the pathogenesis of renal cystic diseases have been identified. Hereditary renal cystic diseases are characterized by genetic mutations that lead to defects in the structure and function of the primary cilia of renal tubular epithelial cells, abnormal proliferation of tubular epithelium, and increased fluid secretion, all of which ultimately result in the development of renal cysts. A better understanding of these pathophysiologic mechanisms is now providing the basis for the development of more targeted therapeutic drugs for some of these disorders. Cross-sectional imaging provides useful information for diagnosis, surveillance, prognostication, and evaluation of treatment response in renal cystic diseases., (© RSNA, 2010.)

Background: Supratentorial hemangioblastomas are rare lesions, occurring either sporadically or in von Hippel-Lindau disease., Objective: Following recent advances in our understanding of the natural history of von Hippel-Lindau-associated cerebellar and spinal hemangioblastomas, we conducted a study of the natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease., Methods: We reviewed a series of 18 supratentorial hemangioblastomas in 13 patients with von Hippel-Lindau disease. Clinical, genetic, and serial imaging data and operative records were analyzed., Results: Hemangioblastomas were most commonly seen in the temporal lobe. Only 6 tumors had a cyst at diagnosis or during follow-up, and only 6 patients had associated symptoms at presentation or during follow-up. The most frequent clinical presentations were intracranial hypertension and visual loss. Of 14 tumors with documented serial imaging, 13 demonstrated tumor growth. Rates and patterns of tumor growth were unique to each patient. The mechanism of cyst formation described in other locations was also demonstrated in the supratentorial region. Patterns of peritumoral edema and rate of cyst formation seemed to be influenced by the presence of anatomic barriers. Germline VHL mutation was identified in all patients, but no specific genotype-phenotype correlation was found, although a familial predisposition is suggested., Conclusion: This series illustrates the wide variation in tumor locations, patterns of growth, and edema progression seen in supratentorial hemangioblastomas and adds to our knowledge of the natural history of hemangioblastomas.

Background: Spinal hemangioblastomas (SH) are definitively treated by en bloc microsurgical resection. Although benign, their highly vascular nature makes resection challenging. A major difficulty involves intraoperative differentiation of vessels supplying the tumor from those supplying the spinal cord., Methods: Twenty patients with SH treated surgically at a single institution were reviewed. Median age was 49 years (range 24 to 70 years). Eleven patients had von Hippel-Lindau syndrome. Six underwent preoperative angiography, of which five underwent embolization. All tumors were posterior and resected through a laminectomy approach. Temporary arterial occlusion (TAO) by aneurysm clip placement with concurrent neuromonitoring was used at the tumor edge to differentiate arteries supplying the tumor from those supplying the healthy spinal cord. Arteries were assumed to not supply important regions of the cord and divided at the tumor surface if there was no change in evoked potentials after 4 minutes of occlusion., Results: Of the 20 patients, 5 improved, 13 remained stable, and 2 worsened. Of the five treated with TAO, two improved, three remained stable, and none worsened. Median McCormick's functional grade of patients treated with TAO was II and improved to I after the operation, whereas that of those not treated with TAO remained unchanged at II (Wilcoxon rank-sum, P = .35)., Conclusions: Temporary arterial occlusion with neuromonitoring is a safe, effective, and simple method of differentiating arteries supplying the tumor only from those that supply the functionally normal spinal cord in the operative management of difficult SH., (Copyright © 2010. Published by Elsevier Inc.)

This study was done to analyze the clinical characteristics of renal cell carcinoma (RCC) in Korean patients with von Hippel-Lindau (VHL) disease. Between January 1996 and July 2008, 1,514 patients were diagnosed with RCC and 24 patients were diagnosed with VHL disease at our institute. We analyzed the clinical characteristics of the 24 patients diagnosed with VHL. The mean age of patients with VHL was 39.2+/-12.6 yr; the mean age of patients with both VHL and RCC was 42.5+/-10.3 yr. Among the 24 patients with VHL, 7 patients had retinal angiomas, 11 had RCC, 16 had renal lesions, 18 had pancreatic lesions and 21 had cerebellar hemangioblastomas. There was no significant difference between survival rates of patients with VHL alone and those with VHL and RCC. However, cancer-specific survival rates were significantly different between patients with both VHL and RCC and patients with sporadic bilateral or multifocal RCC. In our Korean study, the incidence of RCC in patients with VHL disease is 45.8% and the incidence of VHL disease in patients with RCC is 0.73%. Due to the low overall incidence of VHL in Korea, extended multi-institutional studies are needed to establish the true characteristics of VHL disease.

The majority of tumors of the nervous system are sporadic. However, a subset of patients with tumors and their families are predisposed to developing cancers of the central nervous system and other organs because of a germline mutation. In the last decade, many of the genes responsible for these typically autosomal dominant familial tumor syndromes have been identified. Additionally, our understanding of the mechanisms of carcinogenesis in these syndromes has increased, allowing for more targeted therapies for these patients as well as those with sporadic cancers. Because these patients present a unique set of issues regarding diagnosis and neurooncological management, the most common familial cancer syndromes involving the nervous system are reviewed: neurofibromatosis type 1 and 2; tuberous sclerosis complex; von Hippel Lindau, Li-Fraumeni, Gorlin, and Turcot syndrome.

pVHL (von Hippel-Lindau tumor suppressor protein) is the substrate recognition subunit of the CBC(VHL) ubiquitin ligase complex promoting the degradation of hypoxia-inducible factor subunits, HIF-1/2alpha. Mutational inactivation of pVHL causes the hereditary von Hippel-Lindau tumor syndrome, which predisposes affected individuals to hemangioblastomas, renal cell carcinomas, and pheochromocytomas. Whereas the development of hemangioblastomas and renal cell carcinomas has been attributed to impaired HIF-1/2alpha down-regulation by pVHL mutant proteins, the molecular defects underlying the development of pheochromocytomas are still unknown. Here, we present a detailed biochemical analysis of pVHL mutant proteins linked to type 2C (pheochromocytoma only) von Hippel-Lindau disease. Type 2C-associated mutations caused extensive structural perturbations of pVHL, as revealed by the reduced stability, increased proteolytic susceptibility, and dramatically altered NMR spectrum of recombinant, mutant pVHL-ElonginC-ElonginB complexes in vitro. In human cell lines, type 2C-linked mutations destabilized the CBC(VHL) ubiquitin ligase complex and resulted in reduced cellular pVHL levels. Together, our data reveal unexpectedly strong structural defects of type 2C-associated pVHL mutant proteins that are likely to affect both HIF-1/2alpha-related and -unrelated pVHL functions in the pathogenesis of pheochromocytomas.

Objective: To report clinical findings of rare retrobulbar optic nerve hemangioblastomas associated with von Hippel-Lindau disease (VHL)., Design: Retrospective observational case series., Participants: Nine patients with VHL., Methods: The clinical course and magnetic resonance imaging findings of patients with VHL and hemangioblastomas affecting the anterior visual pathway from the intraorbital optic nerve to the optic chiasm are reviewed., Main Outcome Measure: Clinical course of retrobulbar optic nerve hemangioblastomas., Results: The mean age of VHL diagnosis was 24+/-14 years, and mean follow-up was 5+/-4 years. All had other CNS lesions and retinal hemangioblastomas. Approximately 50% (5/9) had a previous enucleation or had visual acuity loss (4/9), some due to other VHL ocular complications. Four patients underwent surgical resection of an intracranial hemangioblastoma. Growth patterns and pathology are similar to those of other hemangioblastomas in the CNS., Conclusions: Although these lesions are rare, patients with VHL who present with signs of optic neuropathy should be evaluated for anterior visual pathway hemangioblastomas impinging on the optic nerve from the orbit to the chiasm. On neuroimaging, the hemangioblastomas may demonstrate chiasmal or optic tract edema, associated cysts, and T(2) flow voids. Lesions may remain radiologically and clinically stable, evolve radiographically with no visual or neurological progression, or progress clinically and radiographically. Patients at risk for visual loss should be considered for surgical resection. Close coordination among neuroradiology, neurosurgery, and ophthalmology patient care teams is advised for optimal management of these patients.

Renal cell carcinoma may be sporadic or occur in the setting of an inherited cancer syndrome, such as von Hippel-Lindau or Birt-Hogg-Dube syndrome. Although the clinical spectrum of heritable renal cancer syndromes varies significantly, commonalities include the often young age of presentation, multifocal and bilateral nature of renal lesions, and autosomal dominant pattern of inheritance. Molecular studies have recently begun to elucidate the genetic abnormalities and subsequent alterations in downstream intracellular signaling cascades that underlie the development of these syndromes. This review will highlight the clinicopathologic and molecular features associated with the diverse array of heritable renal cancer syndromes and emphasize the potential cellular pathways that may be utilized to develop novel treatment strategies for patients with these syndromes.

Purpose of Review: The recent contributions to renal cell carcinoma in the fields of molecular biology and the expanded use of molecularly targeted agents will be reviewed. This study is intended to update prognostic and therapeutic decision-making data and provide perspective on advances in understanding the molecular biology of this disease., Recent Findings: Updates to the currently used prognostic algorithms for renal cell carcinoma are needed, and recently verified prognostic nomograms will be discussed. This comes in the wake of numerous advances in the use of molecularly targeted drugs, which will be reviewed. Finally, advancements in understanding the biology of renal cell carcinoma include the discovery of von Hippel-Lindau associated mechanisms involved in renal cyst formation and renewed appreciation for the influence of this pathway on the tumor cell glucose utilization profile., Summary: Renal cell carcinoma continues to evolve swiftly with the approval of new agents and the maturation of clinical trials to provide relevant structure to treatment decisions. This study will give an overview of the latest concepts in the epidemiology and biology of renal cell carcinoma and provide current surgical and systemic updates for managing renal cell carcinoma.

Object: Despite the frequency of cerebellar hemangioblastomas in von Hippel-Lindau (VHL) disease, their optimum contemporary management has not been defined, and is made complex because of the multiple, progressive, and protean nature of the tumors found in patients with this disorder. To examine modern management and outcomes of cerebellar hemangioblastomas in VHL disease, the authors reviewed findings in patients with this disease who underwent resection of cerebellar hemangioblastomas., Methods: Consecutive patients with VHL disease who underwent surgery for cerebellar hemangioblastoma(s) at the National Institutes of Health were included. Eighty consecutive patients (44 female and 36 male patients) underwent 126 operations for removal of 164 cerebellar hemangioblastomas (age at surgery 37.8+/-10.3 years, follow-up duration 96.0+/-60.3 months). Serial clinical examinations, imaging studies, and operative records were analyzed., Results: Symptoms and signs included headache (94 operations; 75%), ataxia (55%), dysmetria (29%), and hydrocephalus (28%). Although the primary objective of surgery was resection of the hemangioblastoma considered responsible for symptoms (136 of the hemangioblastomas [83%]), 28 additional hemangioblastomas (17%) were removed during the same surgeries. Tumors associated with symptoms were larger (diameter 1.8+/-1.9 cm; volume 2.8+/-3.4 cm3; p<0.05) and more likely to be associated with peritumoral edema or peritumoral cysts (100% associated with edema and/or cyst; p<0.05) than asymptomatic tumors (diameter 1.1+/-0.9 cm; volume 0.7+/-0.4 cm3; 18%). More tumors were located in the posterior (74%) compared with the anterior (26%) half of the cerebellum (p<0.05). Three months after resection, symptom improvement/stabilization had occurred following 124 of the operations (98%). Preoperative hydrocephalus resolved after tumor removal in 33 cases (94%) and did not require cerebrospinal fluid diversion. Long-term imaging follow-up (61.5+/-15.0 months) revealed no recurrences., Conclusions: Symptoms and signs caused by cerebellar hemangioblastomas in VHL disease are associated with edema and peritumoral cyst formation/propagation and are treated safely and effectively with resection. Cerebrospinal fluid diversion is rarely necessary after complete tumor removal in patients with preoperative hydrocephalus. Cerebellar hemangioblastomas are preferentially distributed in the posterior half of the cerebellum, as they are in the brainstem and spinal cord. Tumor recurrence is avoided by meticulous extracapsular resection.

We report a three year follow up of a 35-year-old Indian gentleman who presented with sudden, painless blurring of left (L) eye vision with initial visual acuity (VA) of 6/60. Fundoscopy revealed (L) vitreous haemorrhage and subsequently confirmed a (L) inferotemporal capillary haemangioma. The adjacent area of capillary haemangioma was treated with barricade argon laser photocoagulation to prevent progression of exudative retinal detachment inferiorly. Subsequent follow up showed mild regression of capillary haemangioma with maintenance of (L) eye vision at 6/9.

Hereditary central nervous tumor syndromes are a varied group of conditions that include neurofibromatosis type 1 and 2, tuberous sclerosis, Von Hippel-Lindau disease, and Cowden, Turcot, and Gorlin syndromes. The responsible genes have been identified in most of these disorders. These genes typically act as tumor suppressor genes, maintain normal cellular function and homeostasis, and regulate cell growth and differentiation. Familial central nervous system tumors are mostly inherited as autosomal dominant traits and involve germline mutations. Neoplastic development occurs when a somatic mutation inactivates the second allele. These patients also present unique challenges for their management. This review highlights the clinical manifestations, molecular genetics, pathophysiology, and current treatment options of these disorders with a focus on neuro-oncologic manifestations of the diseases.

The physiologic response to changes in cellular oxygen tension is ultimately governed by a heterodimeric transcription factor called hypoxia-inducible factor (HIF), which, in adaptation to compromised oxygen availability, transactivates a myriad of genes, including those responsible for de novo vascularization, production of oxygen-carrying red blood cells, and anaerobic metabolism. Accumulation of HIF is observed in most types of solid tumors and is frequently associated with poor prognosis and disease progression, underscoring the importance and relevance of HIF in cancer. The protein stability and, thereby, the activity of HIF are principally regulated by the von Hippel-Lindau (VHL) tumor suppressor-containing E3 ubiquitin ligase complex (ECV) that targets the catalytic subunit HIFalpha for oxygen-dependent ubiquitin-mediated destruction. Individuals who inherit germline VHL mutation develop VHL disease, which is characterized by the development of hypervascular tumors in multiple yet specific organs. This review will examine recent progress in our understanding of the molecular mechanisms governing the function of ECV and the significance of consequential regulation of HIF in oncogenesis.

Maintenance of oxygen homeostasis is critical for the survival of multicellular organs. As a result, both invertebrates and vertebrates have developed highly specialized mechanisms to sense changes in oxygen levels and to mount adequate cellular and systemic responses to these changes. Hypoxia, or low oxygen tension, occurs in physiological situations such as during embryonic development, as well as in pathological conditions such as ischemia, wound healing, and cancer. A primary effector of the adaptive response to hypoxia in mammals is the hypoxia-inducible factor (HIF) family of transcription regulators. These proteins activate the expression of a broad range of genes that mediate many of the responses to decreased oxygen concentration, including enhanced glucose uptake, increased red blood cell production, and the formation of new blood vessels via angiogenesis. This latter process is dynamic and results in the establishment of a mature vascular system that is indispensable for proper delivery of oxygen and nutrients to all cells in both normal tissue and hypoxic regions. Angiogenesis is essential for normal development and neoplastic disease as tumors must develop mechanisms to stimulate vascularization to meet increasing metabolic demands. The link between hypoxia and the regulation of angiogenesis is an area of intense research and the molecular details of this connection are still being elaborated. This chapter will provide an overview of current knowledge and highlight new insights into the importance of HIF and hypoxia in angiogenesis in both physiological and pathophysiological conditions.

Visceral manifestations of von Hippel-Lindau disease (VHLD) are generally asymptomatic and their early detection is of considerable help in the management. This communication documents the usefulness of imaging studies in detecting visceral manifestations in two cases of VHLD.

Biallelic inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is a common event in hereditary (von Hippel- Lindau disease) and sporadic hemangioblastomas and clear-cell renal carcinomas. Germ-line VHL mutations are also linked to some hereditary pheochromocytoma families. The VHL gene product, pVHL, interacts with a number of cellular proteins and is implicated in the control of angiogenesis, extracellular matrix formation, cell metabolism, and mitogenesis. The best understood function of pVHL relates to its role as the substrate recognition unit of an E3 ligase that targets the heterodimeric transcription factor HIF (hypoxia-inducible factor) for destruction in the presence of oxygen. Down-regulation of HIF appears to be both necessary and sufficient for renal tumor suppression by pVHL, and HIF is strongly suspected of contributing to hemangioblastoma development as well. Recent work suggests that pVHL's role in pheochromocytoma is not related to HIF but rather to the ability of pVHL to regulate neuronal apoptosis, which is mediated by c-Jun, when growth factors such as NGF become limiting. Loss of pVHL leads to up-regulation of JunB, which antagonizes c-Jun and blunts apoptosis.

This review focuses on CNS hemangioblastomas in von Hippel-Lindau (VHL) disease. The pathogenesis of these lesions remains unclear to date; however, biallelic inactivation of the VHL tumor suppressor gene is thought to be an important step. These benign tumors occur frequently in patients with VHL disease and produce symptoms by mass effect either by the tumor itself or an accompanying cyst or edema. Furthermore, cases of spontaneous hemorrhage have been described. Genetic testing for VHL germline mutations is recommended in all patients with hemangioblastoma and yearly screening, including MRI of the brain and spine, is recommended for all VHL disease patients. Treatment of these tumors is mainly surgical. In general, surgery is indicated in symptomatic hemangioblastomas and eventually also in asymptomatic tumors that exhibit radiographic progression. However, since most VHL disease patients harbor multiple lesions, a careful individual decision must be made in each case. The tumors can usually be completely removed by dissection in the plane between tumor and CNS tissue and coagulating and cutting of the numerous feeding vessels with low power. As long as consequent yearly surveillance is performed and lesions are adequately treated in time, the prognosis of CNS hemangioblastomas in VHL disease is good. Preoperative neurological deficit, however, will not improve after surgery in most patients. Local tumor recurrences are rare.

Pheochromocytoma are tumors derived from chromaffin cells that secrete catecholamines. These catecholamines may lead to increased blood pressure and even death. Historically, pheochromocytoma have been described as 10 tumor, i.e. about 10 were believed to be malignant, 10 were found to be extra-adrenal, and 10 were meant to be bilateral. Also, about 10 were considered to be hereditary. In these instances, they were most often part of either the multiple endocrine neoplasia type 2 (MEN 2) syndrome or the von Hippel-Lindau (VHL) disease. The genes (RET and VHL) involved have been known for several years and their function is the subject of ongoing investigation. Very recently, several genes (SDHD, SDHB, and SDHC) that belong to the mitochondrial complex II have been identified to be involved in the so-called pheochromocytoma-paraganglioma syndrome. Only SDHD and SDHB have so far been implicated in the pathogenesis of pheochromocytoma.

Vasculogenesis is defined by the differentiation of mesodermal precursors into endothelial cells, and angiogenesis by the formation of new vessels from preexisting vessels. Growth factors initiate cellular differentiation but also induce endothelial migration and proliferation; extracellular proteolysis is essential for disassembly and reassembly of endothelial cells to their environmental matrix and allow their migration to elongate the arterial tree. The coagulation and fibrinolysis system, metalloproteinases and adhesion molecules are critical during this step. The balance between pro- and antiangiogenic factors regulates angiogenesis. Ongoing studies dissecting angiogenesis mechanisms offer a new perspective to our understanding of vascular malformations.

The majority of kidney cancers are caused by the mutation of the von Hippel-Lindau (VHL) tumor suppressor gene. VHL protein (pVHL) is part of an E3 ubiquitin ligase complex called VEC that is composed of elongin B, elongin C, cullin 2, NEDD8, and Rbx1. VEC targets a hypoxia-inducible factor (HIF) transcription factor for ubiquitin-mediated destruction selectively in the presence of oxygen. In the absence of wild-type pVHL, as in VHL patients or in the majority of sporadic clear cell renal cell carcinomas, HIF-responsive genes are inappropriately activated even under normoxia. Recent insights into the molecular mechanisms regulating the function of pVHL, and thereby HIF, in the context of kidney cancer are the focus of this review.