Renal involvement in von Hippel-Lindau disease

Kidney scoring surveillance: predictive machine learning models for clear cell renal cell carcinoma growth using MRI

INTRODUCTION

Classification of clear cell renal cell carcinoma (ccRCC) growth rates in patients with Von Hippel-Lindau (VHL) syndrome has several ramifications for tumor monitoring and surgical planning. Using two separate machine-learning algorithms, we sought to produce models to predict ccRCC growth rate classes based on qualitative MRI-derived characteristics.

MATERIAL AND METHODS

We used a prospectively maintained database of patients with VHL who underwent surgical resection for ccRCC between January 2015 and June 2022. We employed a threshold growth rate of 0.5 cm per year to categorize ccRCC tumors into two distinct groups-'slow-growing' and 'fast-growing'. Utilizing a questionnaire of qualitative imaging features, two radiologists assessed each lesion on different MRI sequences. Two machine-learning models, a stacked ensemble technique and a decision tree algorithm, were used to predict the tumor growth rate classes. Positive predictive value (PPV), sensitivity, and F1-score were used to evaluate the performance of the models.

RESULTS

This study comprises 55 patients with VHL with 128 ccRCC tumors. Patients' median age was 48 years, and 28 patients were males. Each patient had an average of two tumors, with a median size of 2.1 cm and a median growth rate of 0.35 cm/year. The overall performance of the stacked and DT model had 0.77 ± 0.05 and 0.71 ± 0.06 accuracies, respectively. The best stacked model achieved a PPV of 0.92, a sensitivity of 0.91, and an F1-score of 0.90.

CONCLUSION

This study provides valuable insight into the potential of machine-learning analysis for the determination of renal tumor growth rate in patients with VHL. This finding could be utilized as an assistive tool for the individualized screening and follow-up of this population.

Outcomes of and indications for renal transplantation in patients with von Hippel Lindau disease

INTRODUCTION AND OBJECTIVE

Von Hippel-Lindau (VHL) is a hereditary cancer syndrome characterized by bilateral, multifocal renal masses. The cumulative impact of extirpative surgery can depreciate renal function and render patients anephric. In the larger end-stage renal disease population, renal transplant offers both excellent quality of life and functional renal replacement. This case control study aims to examine and compare oncologic and functional outcomes of patients who have undergone renal transplant as renal replacement therapy (RRT) to those who remain anephric.

METHODS

Patient charts were retrospectively reviewed of patients with germline testing confirmed VHL between 1980 and 2022 for transplant, all prior surgical history (within and outside the NCI), renal function and graft outcomes. Overall survival (OS) was determined from years after radical nephrectomy, and graft time was defined as years of graft function from initial transplant until failure or patient death. Graft survival was determined as time between transplant(s) to last follow up. Kaplan-Meier analysis was conducted to compare graft times of anephric VHL patients to those with transplanted kidneys.

RESULTS

A total of 23 VHLD patients were identified as either anephric or candidates for transplant. Out of this cohort, 11 total VHLD received 12 total kidney grafts. Median wait time from nephrectomy to transplant was 22.6 months (IQR: 1.02-40.25 months). Median age at transplant was 32 years (IQR: 23-54 years). OS at 5 and 10 years of anephric patients who did not receive a transplant was 33% and 16.7%, respectively. OS rates of the transplant cohort at 10, 15, and 20 years were 91%, 78%, and 58% years, respectively. Median graft time was 161 months (IQR: 56-214 months). Graft survival at 10, 15, and 20 years was 69.8%, 69.8%, and 26.2%, respectively.

CONCLUSIONS

We demonstrate that transplant recipients have decreased mortality with no difference in cancer recurrence compared to those who do not receive renal transplant for RRT. This data can aid in informing providers of the optimal window for early RRT planning in VHL, while also improving patient counseling.

Ocular manifestations in renal diseases

The eyes and kidneys are the targets for end-organ damage in multiple pathologies. Both these organs develop during the same embryonic stage around the fourth to sixth week of gestation, thus sharing a strong correlation between both eye and kidney diseases. Both the eyes and kidneys can be the target of the systemic disease process; however, the eyes can also be affected as a consequence of renal disease or its treatment. Risk factors such as diabetes, hypertension, and smoking are commonly shared between kidney and eye diseases. Ocular manifestations can be predictive of renal disease, and/or patients with renal disease are at higher risk for developing ocular manifestations. Various congenital anomalies of the eyes and kidneys can also present as an oculorenal syndrome. This article summarizes the ocular pathology, which can be seen in renal diseases.

Neurological applications of belzutifan in von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease is a tumor predisposition syndrome caused by mutations in the VHL gene that presents with visceral neoplasms and growths, including clear cell renal cell carcinoma, and central nervous system manifestations, such as hemangioblastomas of the brain and spine. The pathophysiology involves dysregulation of oxygen sensing caused by the inability to degrade HIFα, leading to the overactivation of hypoxic pathways. Hemangioblastomas are the most common tumors in patients with VHL and cause significant morbidity. Until recently, there were no systemic therapies available for patients that could effectively reduce the size of these lesions. Belzutifan, the first approved HIF-2α inhibitor, has demonstrated benefit in VHL-associated tumors, with a 30% response rate in hemangioblastomas and ~30%-50% reduction in their sizes over the course of treatment. Anemia is the most prominent adverse effect, affecting 76%-90% of participants and sometimes requiring dose reduction or transfusion. Other significant adverse events include hypoxia and fatigue. Overall, belzutifan is well tolerated; however, long-term data on dosing regimens, safety, and fertility are not yet available. Belzutifan holds promise for the treatment of neurological manifestations of VHL and its utility may influence the clinical management paradigms for this patient population.

Systemic Therapy Development in Von Hippel-Lindau Disease: An Outsized Contribution from an Orphan Disease

Over the last several decades, an improved understanding of von Hippel-Lindau disease and its underlying biology has informed the successful development of numerous anti-cancer agents, particularly for the treatment of advanced renal cell carcinoma. Most recently, this has culminated in the first regulatory approval for a systemic therapy for VHL disease-associated neoplasms. This review will trace the clinical development of systemic therapies for VHL disease and additionally highlight anticipated challenges and opportunities for future VHL systemic therapy.

Evaluation of tumour surveillance protocols and outcomes in von Hippel-Lindau disease in a national health service

Background

Von Hippel-Lindau (VHL) disease is an inherited tumour predisposition syndrome and a paradigm for the importance of early diagnosis and surveillance. However, there is limited information on the “real world” management of VHL disease.

Methods

A national audit of VHL disease in the United Kingdom.

Results

VHL disease was managed mostly via specialist clinics coordinated through regional clinical genetics services (but frequently involving additional specialties). Over the study period, 19 genetic centres saw 842 individuals (393 males, 449 females) with a clinical and/or molecular diagnosis of VHL disease and 74 individuals (35 male, 39 female) with a prior risk of 50% (affected parent). All centres offered retinal, central nervous system and abdominal surveillance to affected individuals and at-risk relatives though surveillance details differed between centres (but complied with international recommendations). Renal lesions detected on the first surveillance scan were, on average, larger than those detected during subsequent scans and the larger the diameter at detection the greater the likelihood of early intervention.

Conclusions

In a state-funded health care system individuals with a rare inherited cancer predisposition syndrome are generally able to access appropriate surveillance and patient management is improved compared to historical data. The “real world” data from this study will inform the future development of VHL management protocols.

Renal Neoplasia in Tuberous Sclerosis: A Study of 41 Patients

OBJECTIVE

To study the clinical features and identify unique renal neoplasia subtypes and their prognostic implications in individuals with tuberous sclerosis complex (TSC).

PATIENTS AND METHODS

The Mayo Clinic nephrectomy registry included 37 patients with TSC diagnosed between 1970 and 2018. Four additional patients were identified from the pathology consultation and autopsy files. All available renal tumors were further characterized using immunohistochemistry and fluorescence in situ hybridization. Clinicopathologic features and follow-up were obtained from the medical record. The American Association for Cancer Research Project GENIE registry was accessed using cBioPortal for molecular profiling of angiomyolipoma (AML).

RESULTS

A total of 276 renal tumors from 41 patients were analyzed. Renal tumors were classified into 9 distinct morphological subtypes, with AML predominating (238 [86%]). Interestingly, all these tumors acted in a benign fashion except one renal cell carcinoma with clear cells and fibromyomatous stroma and one epithelioid AML that metastasized. Molecular profiling studies revealed that epithelioid AMLs were enriched for alterations of TP53, RB1, and ATRX. Eight patients died of direct complications of TSC, including 3 of end-stage renal disease. To date, none have died of a renal epithelial neoplasm.

CONCLUSION

The identification of unique renal neoplasia subtypes may provide important clues to establish a diagnosis of TSC, and in the somatic setting, this finding has important implications for accurate prognostication. These tumors tend to be indolent, and only 2 of 276 tumors in our study exhibited metastatic behavior. Our results support multidisciplinary management with a focus on preservation of renal function.

MK-6482 as a potential treatment for von Hippel-Lindau disease-associated clear cell renal cell carcinoma

INTRODUCTION

Von Hippel-Lindau (VHL) disease is an inherited autosomal dominant syndrome caused by a germline mutation and/or deletion of the VHL gene. Inappropriate hypoxia-inducible factor (HIF)-mediated transcription of proangiogenic and metabolic genes leads to the development of tumors and cysts in multiple organs. Surgery is a standard treatment for localized tumors with a risk of metastasis or organ dysfunction. Repeated surgeries cause substantial morbidity and have a major impact on quality of life. There is an urgent need to develop effective and safe systemic treatments for VHL disease manifestations. The small-molecule HIF 2 alpha inhibitor MK-6482 (belzutifan) has demonstrated significant efficacy in VHL disease related renal cell carcinomas, hemangioblastomas, and pancreatic neuroendocrine tumors while demonstrating an acceptable safety profile.

AREAS COVERED

This paper reviews the development of the HIF-2 alpha inhibitor, MK-6482, and discusses preliminary results of ongoing phase I/II studies in renal cell carcinoma (RCC) and VHL disease. An examination of ongoing clinical development of MK-6482 and perspectives on potential future developments and challenges are offered.

EXPERT OPINION

Because of its favorable safety profile, its clear efficacy in VHL disease, promising findings in sporadic, advanced RCC, and convenient oral formulation, MK-6482 is expected to become a leading treatment for VHL disease. Among other currently available oral agents, we believe that MK-6482 will be a preferred treatment for VHL-associated RCC.

Clinical characteristics and genetic testing of an atypical familial von Hippel-Lindauzon renal cell carcinoma

Background

A case of familial bilateral von Hippel-Lindauzon (VHL) renal cell carcinoma (RCC) was retrospectively reviewed and the etiological diagnosis was based on clinical characteristics and genetic testing.

Methods

The clinical manifestations and imaging data were gained from the hospital information system (HIS). Peripheral blood samples were collected and genomic DNA and RNA were extracted. Additionally, mutations of VHL gene such as tiny insertion and deletion of base, point mutation and large deletion of gene were then detected and analyzed by DNA sequencing, real-time quantitative PCR and RT-PCR.

Results

Real-time quantitative PCR and RT-PCR products sequencing showed that the number of VHL gene copies in peripheral blood of the patient was decreased, and pathological germline mutation was detected caused by single copy deletion of exon 2 of VHL gene. The patient was diagnosed as atypical VHL RCC according to clinical manifestations and genetic testing outcomes.

Conclusions

VHL RCC can be diagnosed based on its clinical manifestations and genetic testing results.

Familial Kidney Cancer: Implications of New Syndromes and Molecular Insights

CONTEXT

Hereditary cases account for about 5% of all cases of renal cell carcinoma (RCC). With advances in next-generation sequencing, several new hereditary syndromes have been described in the last few years.

OBJECTIVE

To review and summarise the recent preclinical and clinical literature in hereditary renal cancer.

EVIDENCE ACQUISITION

A systematic review of the literature was performed in November 2018 using PubMed and OMIM databases, with an emphasis on kidney cancer, genetics and genomics, clinical criteria, and management.

EVIDENCE SYNTHESIS

Several autosomal dominant hereditary RCC syndromes have been described, including those related to germline pathogenic variants in VHL, MET, FH, TSC1/TSC2, FLCN, SDHA/B/C/D, BAP1, CDC73, and MITF. Clinical spectrum of SDH, BAP1, and MITF is still being defined, although these appear to be associated with a lower incidence of RCC. FH and likely BAP1 RCC are associated with more aggressive disease. Preclinical and clinical studies show that using systemic therapy that exploits specific genetic pathways is a promising strategy.

CONCLUSIONS

There are several well-described hereditary RCC syndromes, as well as recently identified ones, for which the full clinical spectrum is yet to be defined. In the new era of precision medicine, identification of these syndromes may play an important role in management and systemic treatment selection.

PATIENT SUMMARY

This review covers updates in the diagnosis and management of familial kidney cancer syndromes. We describe updates in testing and management of the most common syndromes such as von Hippel-Lindau, and hereditary leiomyomatosis and renal cell carcinoma. We also provide insights into recently described familial kidney cancer syndromes.

Hemangioblastoma Instead of Renal Cell Carcinoma Plays a Major Role in the Unfavorable Overall Survival of Von Hippel-Lindau Disease Patients

Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome characterized by poor survival. The effect of the involvement of each organ on survival remains unclear. Our study aimed to study the effect of the involvement of each organ on survival in VHL disease patients. We retrospectively analyzed 336 patients from 125 families. The onset age was compared between different groups using Mann-Whitney U test and Kruskal-Wallis test. Univariate and multivariate time-dependent Cox regression analyses were conducted to evaluate how survival was influenced by the involvement of each organ. The median survival time for VHL disease patients was 66 years. The onset age was earlier in the central nervous system (CNS) group than in the abdominal group. The involvement of central nervous system hemangioblastoma (CHB) and retinal hemangioblastoma (RA) were independent risk factors for overall survival. The involvement of renal cell carcinoma (RCC) was not a significant risk factor for overall survival. Only RA was a risk factor for CHB-specific survival. This study analyzed the relationship between organ involvement and survival of VHL patients. This may help guide future genetic counseling and clinical decision-making.

Recognizing Hereditary Renal Cancers Through the Microscope: A Pathology Update

A heightened understanding of hereditary renal cancer syndromes and their molecular basis has led to an increased awareness and recognition of these renal neoplasms by pathologists. Because a diagnosis of hereditary renal cell carcinoma has a profound impact on the patient and family members, when and how to raise such a suspicion via pathologic assessment has become an important yet very challenging task. This review discusses key clinicopathologic, immunohistochemical, and genetic characteristics of hereditary renal cancer syndromes, and important differential diagnostic challenges, emphasizing recent pathologic and molecular advances.

Urologic Diseases Germane to the Medical Renal Biopsy: Review of a Large Diagnostic Experience in the Context of the Renal Architecture and Its Environs

The kidney is one of the most complicated organs in development and is susceptible to more types of diseases than other organs. The disease spectrum includes developmental and cystic diseases, involvement by systemic diseases, iatrogenic complications, ascending infections and urinary tract obstruction, and neoplastic diseases. The diagnosis of kidney disease is unique involving 2 subspecialties, urologic pathology and renal pathology. Both renal and urologic pathologists employ the renal biopsy as a diagnostic modality. However, urologic pathologists commonly have a generous specimen in the form of a nephrectomy or partial nephrectomy while a renal pathologist requires ancillary modalities of immunofluorescence and electron microscopy. The 2 subspecialties differ in the disease spectrum they diagnose. This separation is not absolute as diseases of one subspecialty not infrequently appear in the diagnostic materials of the other. The presence of medical renal diseases in a nephrectomy specimen is well described and recommendations for reporting these findings have been formalized. However, urologic diseases appearing in a medical renal biopsy have received less attention. This review attempts to fill that gap by first reviewing the perirenal anatomy to illustrate why inadvertent biopsy of adjacent organs occurs and determine its incidence in renal biopsies followed by a discussion of gross anatomic features relevant to the microscopic domain of the medical renal biopsy. Unsuspected neoplasms and renal cysts and cystic kidney diseases will then be discussed as they create a diagnostic challenge for the renal pathologist who often has limited training and experience in these diseases.

Von Hippel-Lindau disease: a single gene, several hereditary tumors

The Von Hippel-Lindau (VHL) disease is an autosomal dominant disorder characterized by the predisposition for multiple tumors caused by germline mutations in the tumor suppressor gene VHL. This disease is associated with a high morbidity and mortality and presents a variable expression, with different phenotypes from family to family, affecting different organs during the lifetime. The main manifestations of VHL are hemangioblastomas of the central nervous system and retina, renal carcinomas and cysts, bilateral pheochromocytomas, cystic and solid tumors of the pancreas, cystadenomas of the epididymis, and endolymphatic sac tumors. The discovery of any of the syndrome components should raise suspicion of this disease and other stigmas must then be investigated. Due to the complexities associated with management of the various VHL manifestation, the diagnosis and the follow-up of this syndrome is a challenge in the clinical practice and a multidisciplinary approach is needed. The particular relevance to endocrinologists is the detection of pheochromocytomas in 35% and islet cell tumors in 17% of VHL patients, which can be associated with hypertension, hypoglycemia, cardiac arrhythmias, and carcinoid syndrome. The purpose of this review is to define the Von Hippel-Lindau syndrome addressing its clinical aspects and classification, the importance of genetic counseling and to propose a protocol for clinical follow-up.

ZBRK1, a novel tumor suppressor, activates VHL gene transcription through formation of a complex with VHL and p300 in renal cancer

Inactivation or mutation of the VHL gene causes various tumors, including clear cell renal cell carcinoma (ccRCC). In the present study, we identified ZBRK1 as a novel VHL interacting protein by yeast two-hybrid screening, and found a single ZBRK1-binding site located in the VHL promoter region. Ectopic expression of ZBRK1 increases transcriptional activity of the VHL, whereas the depletion of endogenous ZBRK1 by shRNA leads to reduction of VHL expression. We also demonstrate that the inhibition of VEGF transcription by ZBRK1 overexpression is dependent on VHL/HIF pathway. Moreover, VHL is confirmed to serve as a bridge component for the association of ZBRK1 and p300, which leads to an increase in ZBRK1 transcriptional activity in the VHL promoter. We further provide striking evidences that ZBRK1 acts as a tumor suppressor in renal carcinoma by a variety of in vitro and in vivo assays, and ZBRK1 may represent a molecular marker to distinguish patients with ccRCC at high risk from those with a better survival prognosis. Taken together, these findings suggest that ZBRK1 suppresses renal cancer progression perhaps by regulating VHL expression.

Management of von hippel-lindau disease: an interdisciplinary review

Von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited tumour predisposition syndrome with an incidence of 1:36,000 newborns, the estimated prevalence in Europe is about 1-9/100,000. It is associated with an increased risk of developing various benign and malignant tumours, thus affecting multiple organs at different time points in the life of a patient. Disease severity and diversity as well as age at first symptoms vary considerably, and diagnostic delay due to failure of recognition is a relevant issue. The identification of a disease-causing VHL germline mutation subsequently allows family members at risk to undergo predictive genetic testing after genetic counselling. Clinical management of patients and families should optimally be offered as an interdisciplinary approach. Prophylactic screening programs are a cornerstone of care, and have markedly improved median overall survival of affected patients. The aim of this review is to give an overview of the heterogeneous manifestations of the VHL syndrome and to highlight the diagnostic and therapeutic challenges characteristic for this orphan disease. A comprehensive update of the underlying genetic and molecular principles is additionally provided. We also describe how the St. Gallen VHL multidisciplinary group is organised as an example of interdisciplinary cooperation in a tertiary hospital in Switzerland.

Determinants of renal tissue hypoxia in a rat model of polycystic kidney disease

Renal tissue oxygen tension (Po2) and its determinants have not been quantified in polycystic kidney disease (PKD). Therefore, we measured kidney tissue Po2 in the Lewis rat model of PKD (LPK) and in Lewis control rats. We also determined the relative contributions of altered renal oxygen delivery and consumption to renal tissue hypoxia in LPK rats. Po2 of the superficial cortex of 11- to 13-wk-old LPK rats, measured by Clark electrode with the rat under anesthesia, was higher within the cysts (32.8 ± 4.0 mmHg) than the superficial cortical parenchyma (18.3 ± 3.5 mmHg). Po2 in the superficial cortical parenchyma of Lewis rats was 2.5-fold greater (46.0 ± 3.1 mmHg) than in LPK rats. At each depth below the cortical surface, tissue Po2 in LPK rats was approximately half that in Lewis rats. Renal blood flow was 60% less in LPK than in Lewis rats, and arterial hemoglobin concentration was 57% less, so renal oxygen delivery was 78% less. Renal venous Po2 was 38% less in LPK than Lewis rats. Sodium reabsorption was 98% less in LPK than Lewis rats, but renal oxygen consumption did not significantly differ between the two groups. Thus, in this model of PKD, kidney tissue is severely hypoxic, at least partly because of deficient renal oxygen delivery. Nevertheless, the observation of similar renal oxygen consumption, despite markedly less sodium reabsorption, in the kidneys of LPK compared with Lewis rats, indicates the presence of inappropriately high oxygen consumption in the polycystic kidney.

Epidemiology and staging of renal cell carcinoma

Incidence and mortality trends attributed to kidney cancer exhibit marked regional variability, likely related to demographic, environmental, and genetic factors. Efforts to identify reversible factors, which lead to the development of renal cell carcinoma (RCC), have led not only to a greater understanding of the etiology of RCC but also the genetic and histologic characteristics of renal tumors. This article describes this evolution by discussing contemporary RCC incidence and mortality data, the risk factors for development of RCC, the histologic features, and anatomic and integrated staging systems that guide treatment.

[Epidemiology, treatment and follow-up of central nervous system hemangioblastomas in von Hippel-Lindau disease]

INTRODUCTION

Central nervous system (CNS) hemangioblastomas (HGB) are rare vascular tumors. The goal of this study was to analyze their epidemiology, treatment and prognosis in association with von Hippel-Lindau (VHL) disease.

METHODS

We retrospectively reviewed a series of patients treated in our department for a CNS HGB with VHL disease between 1996 and 2008. We analyzed pre- and postoperative clinical and radiological characteristics, number of visceral lesions (fundoscopy, abdomino-pelvian CT, metanephrines), clinical course (modified Rankin Scale and McCormick scale) and late prognosis (Kaplan-Meier survival curves).

RESULTS

We studied 19 cases (sex-ratio 0.9, mean age 36). The mean time to diagnosis was 61days. The main symptom was intracranial hypertension for cerebellar lesions (7/15) and a sensitive-motor deficit for medulla oblongata (2/5) or spinal lesions (5/11). Preferred locations were cerebellum (15/31), often nodulo-cystic appearance, followed by spinal cord (11/31), frequently coming with adjacent syringomyelia. Multiple locations and visceral lesions were found in two-third of the cases. Surgical removal was complete in more than three-quarter of the cases. Mean follow-up duration was 9years. Postoperative mortality rate was 16%. In cerebellar and medulla oblongata locations together, final mRS was ≤1 in 17 of the 20 cases. In spinal cord locations, final McCormick score was ≤2 in all the cases. After delayed follow-up, about two-third of patients experienced recurrence or new progressive CNS lesions.

CONCLUSION

HGB are rare CNS tumors. VHL disease should be considered when an HGB is diagnosed before 30, is located at the spinal cord, comes with multiple other CNS lesions or with typical peripheral lesions. Microsurgical removal is the gold standard treatment and can offer good functional results.

Hereditary renal tumor syndromes: imaging findings and management strategies

OBJECTIVE

It is not rare for the radiologist to identify multiple renal masses and be the first to raise the possibility of a hereditary renal tumor syndrome. Characteristic renal and extrarenal imaging findings aid in making the correct diagnosis. The imaging findings, screening guidelines, and management techniques for the most common hereditary renal tumor syndromes are reviewed.

CONCLUSION

Hereditary renal tumor syndromes have specific screening guidelines and unique management techniques in which imaging plays a central role.

Epigenetic expansion of VHL-HIF signal output drives multiorgan metastasis in renal cancer

Inactivation of the von Hippel-Lindau tumor suppressor gene, VHL, is an archetypical tumor-initiating event in clear cell renal carcinoma (ccRCC) that leads to the activation of hypoxia-inducible transcription factors (HIFs). However, VHL mutation status in ccRCC is not correlated with clinical outcome. Here we show that during ccRCC progression, cancer cells exploit diverse epigenetic alterations to empower a branch of the VHL-HIF pathway for metastasis, and the strength of this activation is associated with poor clinical outcome. By analyzing metastatic subpopulations of VHL-deficient ccRCC cells, we discovered an epigenetically altered VHL-HIF response that is specific to metastatic ccRCC. Focusing on the two most prominent pro-metastatic VHL-HIF target genes, we show that loss of Polycomb repressive complex 2 (PRC2)-dependent histone H3 Lys27 trimethylation (H3K27me3) activates HIF-driven chemokine (C-X-C motif) receptor 4 (CXCR4) expression in support of chemotactic cell invasion, whereas loss of DNA methylation enables HIF-driven cytohesin 1 interacting protein (CYTIP) expression to protect cancer cells from death cytokine signals. Thus, metastasis in ccRCC is based on an epigenetically expanded output of the tumor-initiating pathway.

Von Hippel-Lindau: how a rare disease illuminates cancer biology

Von Hippel-Lindau (VHL) disease is a rare autosomal dominant syndrome (1/36,000 live births) with highly penetrance that predispose to the development of a panel of highly vascularized tumors (model of tumoral angiogenesis). Main manifestations include central nervous system (CNS) and retinal haemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas (RCC), phaeochromocytomas and pancreatic neuroendocrine tumors. RCC has become the first potential cause of mortality and VHL disease is the main cause of inherited RCC. The disease is caused by germline mutations in the VHL tumor-suppressor gene that plays a major role in regulation of the oxygen-sensing pathway by targeting the hypoxia-inducible factor HIF for degradation in proteasome. VHL has also major HIF-independent functions, specially in regulation of primary cilium, extracellular matrix and apoptosis. Somatic inactivation of the VHL gene is the main molecular event in most sporadic RCC and the treatment of advanced RCC has been revolutionized by targeted therapy with drugs that block angiogenesis. These drugs are now in first line in metastatic sporadic RCC and have shown promising results for RCC, pancreatic neuroendocrine tumors and malignant pheochromocytomas in VHL patients.

Spectrum of preneoplastic and neoplastic cystic lesions of the kidney

CONTEXT

Cystic lesions of the kidney may be accompanied by a range of neoplasms with distinct prognoses and future risks of developing additional tumors. In addition, some renal tumors, with or without accompanying renal cysts, may show a prominent cystic component. In the adult population, neoplasms occurring in a background of renal cystic diseases and cystic renal neoplasms often pose diagnostic challenges because of their many overlapping features.

OBJECTIVE

To review the clinicopathologic characteristics of common entities in the spectrum of neoplastic and potential preneoplastic cystic lesions encountered in adults, with an emphasis on renal cystic diseases associated with tumor development and on renal neoplasms with predominantly cystic morphology.

DATA SOURCES

The relevant English-language literature was reviewed, accompanied by the authors' experience at their practicing institution.

CONCLUSIONS

The presence of multiple renal cysts, both acquired and syndromic, can be associated with a variety of renal tumors. The morphology of the cysts and associated tumor types can help predict the genetic or acquired basis of the lesions, and particularly in specimens with no accompanying pertinent clinical history, such potential associations should be suggested in surgical pathology reports.

CT and MRI appearances and radiologic staging of pediatric renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is an uncommon but noteworthy primary pediatric renal malignancy. There is a paucity of published data regarding the CT/MRI appearances and accuracy of pretreatment radiologic staging of this form of cancer in children.

OBJECTIVE

To review the various CT/MRI appearances of pediatric RCC and assess the accuracy of pretreatment radiologic staging using these imaging modalities.

MATERIALS AND METHODS

Institutional Departments of Pathology and Radiology records were searched from 1995 through 2010 for children (younger than 18 years of age) with RCC. Available pretreatment contrast-enhanced abdominopelvic CT and MRI examinations were reviewed by two radiologists. Pertinent imaging findings were documented by consensus, and correlation was made between radiologic and surgicopathological TNM staging.

RESULTS

Pretreatment imaging studies from 10 RCCs in nine children (four girls and five boys; mean age 12.9 years) were reviewed. The mean size of the primary tumor was 6.2 cm (range, 1.5-12.6 cm). Ninety percent of RCCs demonstrated heterogeneous postcontrast enhancement. Fifty percent of masses had associated hemorrhage, while 40% contained internal calcification. Regarding TNM staging, N staging was correct for 10 of 10 tumors, while M staging was correct for 10 of 10 tumors. Imaging correctly staged only 4 of 10 tumors with respect to T stage. Radiologic and surgicopathological overall staging were concordant for 8 of 10 tumors.

CONCLUSION

Pediatric RCCs typically present as large, heterogeneous masses, and they commonly hemorrhage and contain internal calcification. Radiologic and surgicopathological overall TNM staging are frequently concordant, although radiologic T staging is often incorrect.

The non-neoplastic kidney in tumor nephrectomy specimens: what can it show and what is important?

Surgical nephrectomy is a procedure that has been performed for nearly 100 years. In the presence of a normal contralateral kidney, such as in a renal transplant donor or child with Wilms tumor, it is a benign procedure without deleterious consequences on the remaining kidney. However, many adults and some children postnephrectomy will develop chronic kidney disease. The non-neoplastic kidney in tumor resections may harbor a large number of developmental and acquired diseases predictive of this outcome or that convey other medically significant information. Examination of the non-neoplastic kidney is a fertile opportunity to identify these unsuspected conditions that may ultimately dictate the subsequent clinical course and influence the medical care provided. This review discusses the consequences of unilateral and partial nephrectomy, and illustrates many conditions that may be encountered in the non-neoplastic cortex with a discussion of their clinical implications.

Glomerulocystic kidney: one hundred-year perspective

CONTEXT

Glomerular cysts, defined as Bowman space dilatation greater than 2 to 3 times normal size, are found in disorders of diverse etiology and with a spectrum of clinical manifestations. The term glomerulocystic kidney (GCK) refers to a kidney with greater than 5% cystic glomeruli. Although usually a disease of the young, GCK also occurs in adults.

OBJECTIVE

To assess the recent molecular genetics of GCK, review our files, revisit the literature, and perform in silico experiments.

DATA SOURCES

We retrieved 20 cases from our files and identified more than 230 cases published in the literature under several designations.

CONCLUSIONS

Although GCK is at least in part a variant of autosomal dominant or recessive polycystic kidney disease (PKD), linkage analysis has excluded PKD-associated gene mutations in many cases of GCK. A subtype of familial GCK, presenting with cystic kidneys, hyperuricemia, and isosthenuria is due to uromodullin mutations. In addition, the familial hypoplastic variant of GCK that is associated with diabetes is caused by mutations in TCF2, the gene encoding hepatocyte nuclear factor-1beta. The term GCK disease (GCKD) should be reserved for the latter molecularly recognized/inherited subtypes of GCK (not to include PKD). Review of our cases, the literature, and our in silico analysis of the overlapping genetic entities integrates established molecular-genetic functions into a proposed model of glomerulocystogenesis; a classification scheme emerged that (1) emphasizes the clinical significance of glomerular cysts, (2) provides a pertinent differential diagnosis, and (3) suggests screening for probable mutations.

Von Hippel Lindau syndrome

Von Hippel-Lindau syndrome (VHLS) is an autosomal dominant familial cancer syndrome arising from germ-line inactivation of the VHL gene on the short arm of chromosome 3. VHLS manifests in a myriad of hyper-vascular tumors of both benign and malignant nature. Incidence of VHLS is roughly 1 in 36,000 live births and has over 90% penetrance by the age of 65. Improved understanding of the natural history and biology of VHLS has led to the introduction of screening protocols, early interventions and improved treatments, all of which resulted in a substantially improved prognosis for this disease. Further details regardingvariegated molecular pathways and mechanisms ofVHLS are emerging with the subsequent advent of novel treatment protocols that are currently in clinical trials.

Renal cystic diseases and renal neoplasms: a mini-review

The past two decades have witnessed recognition of several new types of renal cell carcinoma, each with distinct cytogenetic abnormalities. Included are several genetic and acquired cystic kidney diseases associated with development of renal cell carcinoma, the topic of this review. The risk in patients with autosomal dominant polycystic kidney disease is not accurately known but may be slightly increased. The risk for patients with von Hippel-Lindau disease is substantial, and death from renal cancer is common. For patients with tuberous sclerosis complex, the challenge is recognition of the occasional malignancy arising in a field of many benign tumors. Patients with end-stage kidney disease and acquired cystic kidney disease may develop a variety of renal cell carcinoma types. Progress in understanding the molecular basis of renal cyst formation and neoplastic disease has fostered development of targeted therapies that now hold promise for a group of neoplasms whose cure was traditionally dependent on surgical approaches.

Von Hippel-Lindau (VHL) disease: an update on the clinico-pathologic and genetic aspects

von Hippel-Lindau (VHL) disease is an inherited multisystem familial cancer syndrome caused by mutations of the VHL gene on chromosome 3p25. A wide variety of neoplastic processes are known to be associated with VHL disease. The consequences of the VHL mutations and the pathway for tumor development continue to be elucidated. This paper will detail the variety of tumors associated with VHL disease and discuss the genetic mechanisms that lead to the predisposition for neoplasia.

Local recurrence after nephron-sparing surgery in von Hippel-Lindau disease

OBJECTIVES

To evaluate the risks of local recurrence and repeat surgery after nephron-sparing surgery (NSS) in von Hippel-Lindau (VHL) disease to propose a therapeutic strategy to patients.

METHODS

A total of 21 patients with VHL disease and renal tumors were followed up from February 1987 to August 2005. Surgical resection of all tumors was chosen when the largest tumor exceeded a diameter of 30 mm.

RESULTS

Of the 21 patients, 18 underwent surgery at a mean age of 38.5 years (range 24 to 69). The median follow-up of the series was 100 months. Of the 17 patients treated by NSS, 8 developed a recurrence. The mean time to local recurrence was 53 +/- 38.8 months (range 10 to 115), and the recurrence tumors grew at a stable mean rate of 0.34 +/- 0.32 cm/yr (range 0.1 to 1.08). Repeat NSS was performed on the same kidney in 2 cases and eight recurrences were kept under surveillance. The disease-specific survival rate was 93.8% at 10 years. The local recurrence rate was 45.6% at 5 years and 83.7% at 10 years. The overall repeat surgery rate was 23.1% at 5 years and 63.4% at 10 years. No metastasis or chronic renal insufficiency was observed in patients undergoing NSS only.

CONCLUSIONS

Five years after NSS, the risk of developing new tumors in the same kidney and the overall risk of repeat surgery was about 50% and 25%, respectively. However, the strategy of elective NSS and close surveillance preserved renal function without increasing the risk of metastasis.

Involvement of hypoxia-inducible transcription factors in polycystic kidney disease

In polycystic kidney disease (PKD), erythropoietin (EPO) production and interstitial vascularization are increased compared with other kidney diseases. EPO and several angiogenic factors are controlled by hypoxia-inducible transcription factors (HIFs), which are composed of a constitutive beta-subunit and two alternative alpha-subunits (HIF-1alpha, HIF-2alpha). We hypothesized that cyst expansion may result in pericystic hypoxia and consecutive up-regulation of HIF and thus examined the expression of HIF-alpha and HIF target genes in human PKD and in a rodent PKD model. HIF-1alpha and HIF-2alpha were found to be up-regulated in cyst epithelium and cells of cyst walls, respectively. The distinct expression pattern of the HIF-alpha isoforms closely resembles the respective pattern in normal kidneys under systemic hypoxia. Pimonidazole staining, a marker for tissue hypoxia, confirmed the existence of regional hypoxia in polycystic kidneys. Immunohistochemistry for selected target genes implicated a role for HIF-1alpha in vascular endothelial growth factor and Glut-1 activation and HIF-2alpha in endoglin and EPO stimulation. Polycystin-deficient cells showed physiological, oxygen-dependent HIF-alpha modulation, excluding a direct influence of polycystin deficiency on HIF-alpha regulation. In conclusion, HIF accumulation in human and rat PKD seems to be responsible for increased EPO production and pericystic hypervascularity and may have an impact on progression of PKD.

Renal cystic diseases: a review

This review aims to assist in the categorization of inherited, developmental, and acquired cystic disease of the kidney as well as to provide a pertinent, up-to-date bibliography. The conditions included are autosomal-dominant polycystic kidney disease, autosomal-recessive polycystic kidney disease, unilateral renal cystic disease (localized cystic disease), renal simple cysts, multicystic dysplastic kidney, pluricystic kidney of the multiple malformation syndromes, juvenile nephronophthisis and medullary cystic disease, medullary sponge kidney, primary glomerulocystic kidney disease, and glomerulocystic kidney associated with several systemic disorders mainly of genetic or chromosomal etiology, cystic kidney in tuberous sclerosis, and in von Hippel-Lindau syndrome, cystic nephroma, cystic variant of congenital mesoblastic nephroma, mixed epithelial stromal tumor of the kidney, renal lymphangioma, pyelocalyceal cyst, peripylic cyst and perinephric pseudocyst, acquired renal cystic disease of long-term dialysis, and cystic renal cell carcinoma and sarcoma. Whereas the gross and histologic appearance of some of these conditions may be diagnostic, clinical and sometimes molecular studies may be necessary to define other types.

Hereditary hormone excess: genes, molecular pathways, and syndromes

Hereditary origin of a tumor helps toward early discovery of its mutated gene; for example, it supports the compilation of a DNA panel from index cases to identify that gene by finding mutations in it. The gene for a hereditary tumor may contribute also to common tumors. For some syndromes, such as hereditary paraganglioma, several genes can cause a similar syndrome. For other syndromes, such as multiple endocrine neoplasia 2, one gene supports variants of a syndrome. Onset usually begins earlier and in more locations with hereditary than sporadic tumors. Mono- or oligoclonal ("clonal") tumor usually implies a postnatal delay, albeit less delay than for sporadic tumor, to onset and potential for cancer. Hormone excess from a polyclonal tissue shows onset at birth and no benefit from subtotal ablation of the secreting organ. Genes can cause neoplasms through stepwise loss of function, gain of function, or combinations of these. Polyclonal hormonal excess reflects abnormal gene dosage or effect, such as activation or haploinsufficiency. Polyclonal hyperplasia can cause the main endpoint of clinical expression in some syndromes or can be a precursor to clonal progression in others. Gene discovery is usually the first step toward clarifying the molecule and pathway mutated in a syndrome. Most mutated pathways in hormone excess states are only partly understood. The bases for tissue specificity of hormone excess syndromes are usually uncertain. In a few syndromes, tissue selectivity arises from mutation in the open reading frame of a regulatory gene (CASR, TSHR) with selective expression driven by its promoter. Polyclonal excess of a hormone is usually from a defect in the sensor system for an extracellular ligand (e.g., calcium, glucose, TSH). The final connections of any of these polyclonal or clonal pathways to hormone secretion have not been identified. In many cases, monoclonal proliferation causes hormone excess, probably as a secondary consequence of accumulation of cells with coincidental hormone-secretory ability.

Maladie de von Hippel-Lindau : progrès génétiques et cliniques récents

Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome that predisposes to the development of a panel of highly vascularized tumors including CNS and retinal hemangioblastomas, endolymphatic sac tumors, clear-cell renal cell carcinomas (RCC), pheochromocytomas and pancreatic neuroendocrine tumors. CNS hemangioblastomas and RCC are the two main life-threatening manifestations. The disease is caused by germline mutations in the VHL tumor-suppressor gene that plays a major role in regulating the oxygen-sensing pathway by targeting the hypoxia-inducible factor HIF for degradation in proteasome. Somatic inactivation of the VHL gene occurs also in most sporadic RCC and sporadic CNS hemangioblastomas. The demonstration of the critical role of VHL in angiogenesis is paving the way for the development of new specific drugs that could represent an attractive potential treatment for VHL but also for sporadic RCC and other cancers.

The phakomatoses

The "phakomatosis" concept was formulated early in the twentieth century by the ophthalmologist van der Hoeve. He included 3 disorders in the group-neurofibromatosis, tuberous sclerosis complex, and von Hippel-Lindau syndrome--on the basis of the occurrence of patchy ophthalmologic manifestations in each disorder. Since the name was coined, much has been learned about the pathogenesis of these 3 disorders. It is clear that 2 of them--neurofibromatosis and tuberous sclerosis--are collective terms for multiple disorders. Each of the conditions is caused by distinct genetic defects, with little commonality in terms of protein function. Yet, in some respects, the disorders share a pathogenetic mechanism, that of the tumor suppressor gene. This review will briefly describe these disorders in light of what has been learned about underlying molecular pathogenesis. In each case, genetic testing is beginning to be available; principles of the use of genetic tests will be described.

The phakomatoses

The phakomatoses are a diverse set of disorders related principally by a similar tendency to produce patchy manifestations that affect the nervous system and various other tissues. All of the disorders involve the occurrence of benign neoplasms or hamartomatous growths, and all involve the action of a distinct gene that functions as a tumor suppressor. At present, none of the phakomatoses is amenable to effective medical treatment, so management is limited to surveillance and treatment of progressive lesions. The radiologist plays a key role in this management, participating in diagnosis and follow-up of affected patients.