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

Occurrence of papillary renal cell carcinoma and clear cell renal carcinoma in a patient: A unique case report

RATIONALE

Renal cancer is one of the most common neoplasms in both males and females. Precise diagnosis, grading, and staging are very important for the outcome and the prognosis of the malignant process. Renal carcinoma disorders are presented by kidney tumors usually of the same histological type. The presence of various tumor histological types is an extremely rare event.

PATIENT CONCERNS

Two different histological types of tumors were found in the left kidney of a 74-year-old man.

DIAGNOSES

The diagnosis obtained was papillary renal cell carcinoma type 1 and clear cell renal carcinoma with pathologic stage T2N0M1.

INTERVENTIONS AND OUTCOMES

After abdominal ultrasound and computer tomography, consultation with an anesthesiologist, and a cardiologist, the patient underwent radical left nephrectomy.

LESSONS

Pathologists must be aware of the possibility of the presence of more than one histological type of renal carcinoma due to genomic alterations. Further genetic investigations must be conducted to identify the specific type and thus the treatment will be most precise.

Hypoxia-induced TIMAP upregulation in endothelial cells and TIMAP-dependent tumor angiogenesis

TGFβ-inhibited membrane associated protein (TIMAP), the endothelial cell-predominant protein phosphatase 1β regulatory subunit also known as PPP1R16B, promotes in vitro endothelial cell proliferation and angiogenic sprouting. TIMAP was first identified as a target of TGF-β1-mediated repression, but the molecular pathways regulating its expression in endothelial cells are not well-defined. This study examined the role of bone morphogenetic factor 9 (BMP9), hypoxia, and angiogenic growth factors in the regulation of TIMAP expression and determined whether TIMAP plays a role in tumor angiogenesis and growth in vivo. BMP9, which potently activated the SMAD1/5/8 pathway in endothelial cells, significantly reduced TIMAP mRNA and protein expression. Conversely, hypoxia and the prolyl hydroxylase inhibitor Roxadustat raised TIMAP mRNA and protein levels by inhibiting the SMAD1/5/8 pathway. Angiogenic growth factors, including VEGFA and IGF-I, raised endothelial TIMAP levels partly by attenuating SMAD1/5/8 pathway activation, but also through SMAD1/5/8-independent mechanisms. Cultured breast cancer E0771 cells released mediators that raised TIMAP expression in endothelial cells, effects that were inhibited by the VEGF inhibitor Sunitinib in conjunction with the IGF-1 inhibitor Picropodophyllin. In the mouse E0771 breast cancer model in vivo, tumor growth and tumor angiogenesis were markedly attenuated in TIMAP deficient, compared with wild-type littermates. These findings indicate that TIMAP plays a critical proangiogenic function during tumor angiogenesis in vivo, likely through hypoxia-driven inhibition of the SMAD1/5/8 pathway and through the elaboration of angiogenic growth factors by tumor cells.NEW & NOTEWORTHY The protein phosphatase 1 regulatory subunit TGFβ-inhibited membrane associated protein (TIMAP), known to activate AKT in endothelial cells (EC), was shown here to be repressed by bone morphogenetic factor 9 (BMP9). Hypoxia and angiogenic growth factors induced TIMAP expression by inhibiting the BMP9 pathway. In a mouse breast cancer model, TIMAP deletion inhibited tumor angiogenesis and tumor growth. Therefore, the proangiogenic functions of TIMAP are induced by hypoxia and angiogenic growth factors.

Genome editing and cancer therapy: handling the hypoxia-responsive pathway as a promising strategy

The precise characterization of oxygen-sensing pathways and the identification of pO2-regulated gene expression are both issues of critical importance. The O2-sensing system plays crucial roles in almost all the pivotal human processes, including the stem cell specification, the growth and development of tissues (such as embryogenesis), the modulation of intermediate metabolism (including the shift of the glucose metabolism from oxidative to anaerobic ATP production and vice versa), and the control of blood pressure. The solid cancer microenvironment is characterized by low oxygen levels and by the consequent activation of the hypoxia response that, in turn, allows a complex adaptive response characterized mainly by neoangiogenesis and metabolic reprogramming. Recently, incredible advances in molecular genetic methodologies allowed the genome editing with high efficiency and, above all, the precise identification of target cells/tissues. These new possibilities and the knowledge of the mechanisms of adaptation to hypoxia suggest the effective development of new therapeutic approaches based on the manipulation, targeting, and exploitation of the oxygen-sensor system molecular mechanisms.

Potential Role of VHL, PTEN, and BAP1 Mutations in Renal Tumors

The genetic profiling of renal tumors has revealed genomic regions commonly affected by structural changes and a general genetic heterogeneity. The VHL, PTEN, and BAP1 genes are often mutated in renal tumors. The frequency and clinical relevance of these mutations in renal tumors are still being researched. In our study, we investigated VHL, PTEN, and BAP1 genes and the sequencing of 24 samples of patients with renal tumors, revealing that VHL was mutated at a noticeable frequency (25%). Six of the investigated samples showed mutations, and one genetic polymorphism (rs779805) was detected in both heterozygote and homozygote forms. PTEN gene mutation was observed in only one sample, and one specimen showed genetic polymorphism. In the case of the BAP1 gene, all of the samples were wild types. Interestingly, VHL mutation was detected in two female patients diagnosed with AML and in one with oncocytoma. We assume that VHL or PTEN mutations may contribute to the development of human renal cancer. However, the overall mutation rate was low in all specimens investigated, and the development and prognosis of the disease were not exclusively associated with these types of genetic alterations.

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

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

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

Clear cell and papillary renal cell carcinomas in hereditary papillary renal cell carcinoma (HPRCC) syndrome: a case report

Background

Hereditary papillary renal cell carcinoma (HPRCC) is a rare autosomal dominant disease characterized by the development of multiple and bilateral papillary type I renal cell carcinomas (RCC) and papillary adenomas caused by activating mutations in the MET proto-oncogene. Classically, distinctive histological features of RCC are described according to the familial renal cell carcinoma syndrome. To date, no clear cell RCC has been reported in HPRCC syndrome.

Case presentation

We describe the case of a 51-year-old man with a germline MET mutation detected on peripheral blood testing, and no germline VHL mutation, who developed numerous papillary tumors but also unexpectedly clear cell renal cell carcinomas. During the follow-up, an adrenal metastasis was observed 7 years after the initial diagnosis corresponding to a clear cell RCC metastasis. By immunohistochemistry, clear cell tumors showed focal cytokeratin 7, moderate racemase, and diffuse and membranous CAIX expression, while papillary tumors expressed strong diffuse cytokeratin 7 and racemase without CAIX positivity. Using FISH, VHL deletion was observed in one of the clear cell tumors, and the metastatic clear cell tumor presented a trisomy of chromosomes 7 and 17. These last genomic alterations are usually detected in papillary RCC, highlighting the potential link between both histological subtypes of tumors and the HPRCC syndrome.

Conclusions

The pathologist must be aware that the presence of a non-papillary RCC associated with numerous papillary tumors should not exclude the diagnostic suspicion of HPRCC and thus to perform a thorough genomic study.

Involvement of PBRM1 in VHL disease-associated clear cell renal cell carcinoma and its putative relationship with the HIF pathway

Von Hippel-Lindau (VHL) disease is the main cause of inherited clear-cell renal cell carcinoma (ccRCC) and is caused by germline mutations in the VHL tumor suppressor gene. Bi-allelic VHL alterations lead to inactivation of pVHL, which plays a major role by downstream activation of the hypoxia inducible factor (HIF) pathway. Somatic VHL mutations occur in 80% of sporadic ccRCC cases and the second most frequently mutated gene is polybromo 1 (PBRM1). As there is currently no data regarding PBRM1 involvement in VHL disease-associated ccRCC, the aim of the present study was to assess the PBRM1 mutational status, and PBRM1 and HIF expression in VHL disease-associated ccRCC series compared with a sporadic series. PBRM1 gene was screened by Sanger sequencing for 23 VHL-disease-associated ccRCC and 22 sporadic ccRCC cases. Immunohistochemical studies were performed to detect the expression of PBRM1, HIF1 and HIF2 for all cases. In VHL-associated tumors, 13.0% (n=3/23) had PBRM1 somatic mutations and 17.4% (n=4/23) had a loss of PBRM1 nuclear expression. In sporadic cases, 27.3% (n=6/22) showed PBRM1 somatic mutations and 45.5% (n=10/22) had a loss of PBRM1 nuclear expression. Loss of PBRM1 was associated with an advanced tumor stage. HIF1-positive tumors were observed more frequently in the VHL-associated ccRCC than in the sporadic series. Furthermore, in the VHL cohort, PBRM1 expression appeared to be associated more with HIF1 than with HIF2. Given that hereditary tumors tend to be less aggressive, these results would suggest that co-expression of PBRM1 and HIF1 may have a less oncogenic role in VHL-associated ccRCC.

Multimodal image-guided ablation on management of renal cancer in Von-Hippel-Lindau syndrome patients from 2004 to 2021 at a specialist centre: A longitudinal observational study

OBJECTIVES

To analyse the safety, technical feasibility, long-term renal function and oncological outcome of multimodal technologies in image-guided ablation (IGA) for renal cancer in Von-Hippel-Lindau (VHL) patients, and to evaluate factors that may influence the outcome.

METHODS

Retrospective analysis of a prospective database of VHL patients who underwent IGA at a specialist centre. Patient's demographics, treatment energy, peri-operative outcome and oncological outcomes were recorded. Statistical analysis was performed to determine factors associated with complication and renal function reduction. The overall, 5 and 10-year cancer specific (CS), local recurrence-free (LRF) and metastasis-free (MF) survival rates were presented with Kaplan-Meier Curves.

RESULTS

From 2004 to 2021, 17 VHL patients (age 21-68.2) with a mean (±SD) RCC size of 2.06 ± 0.92 cm received IGA. Median (IQR) RCCs per patient was 3 (2-4) over the course of follow up. Fifty-four RCCs were treated using radiofrequency ablation (n = 11), cryoablation (n = 38) and irreversible electroporation (n = 8) in 50 sessions. Primary and overall technical success rate were 94.4% (51/54) and 98% (53/54). One CD-III complication with proximal ureteric injury. Five patients in seven treatment sessions experienced a >25% reduction of eGFR immediately post-IGA. All patients have preservation of renal function at a median follow-up of 79 (51-134) months. The 5 and 10-year CS, LRF and MF survival rates are 100%, 97.8% and 100%. Whilst, the 5 and 10-year overall survival rate are100% and 90%.

CONCLUSION

Multimodal IGA of de novo RCC for VHL patients is safe and has provided long term preservation of renal function and robust oncological durability.

The Endothelial Landscape and Its Role in Von Hippel-Lindau Disease

Von Hippel–Lindau disease (VHL) is a rare hereditary disease characterized by the predisposal to develop different types of highly vascularized tumors. VHL patients carry a VHL mutation that causes partial lack of functional VHL protein (pVHL) in all cells, and a total lack thereof in cells harboring a second hit mutation. Absence of pVHL generates a prolonged state of pseudo-hypoxia in the cell due to accumulation of hypoxia inducible factor, an important transcription factor regulating pro-tumorigenic genes. The work here presented focuses on characterizing the endothelium of VHL patients, by means of blood outgrowth endothelial cells (BOECs). Transcriptome analysis of VHL-derived BOECs, further supported by in vitro assays, shows that these cells are at a disadvantage, as evidenced by loss of cell adhesion capacity, angiogenesis defects, and immune response and oxidative metabolic gene downregulation, which induce oxidative stress. These results suggest that the endothelium of VHL patients is functionally compromised and more susceptible to tumor development. These findings contribute to shedding light on the vascular landscape of VHL patients preceding the second hit mutation in the VHL gene. This knowledge could be useful in searching for new therapies for these patients and other vascular diseases.

Amyloidogenic Properties of Peptides Derived from the VHL Tumor Suppressor Protein

The von Hippel-Lindau tumor suppressor protein (pVHL) is involved in maintaining cellular oxygen homeostasis through the regulated degradation of HIF-α. The intrinsically disordered nature of pVHL makes it prone to aggregation that impairs its function, and this is further aggravated in mutant versions of the protein, thus promoting tumor development. By using in silico analysis, we predicted six peptide fragments from pVHL to be amyloidogenic. This was verified for two of the peptides by biophysical approaches, which demonstrated self-assembly and formation of β-sheet-rich aggregates, which, under transmission electron microscopy, atomic force microscopy, and X-ray diffraction, displayed typical fibrillar amyloid characteristics. These motifs may serve as proxies for exploring the nature of pVHL aggregation.

Phakomatoses and Endocrine Gland Tumors: Noteworthy and (Not so) Rare Associations

Phakomatoses encompass a group of rare genetic diseases, such as von Hippel-Lindau syndrome (VHL), neurofibromatosis type 1 (NF1), tuberous sclerosis complex (TSC) and Cowden syndrome (CS). These disorders are due to molecular abnormalities on the RAS-PI3K-Akt-mTOR pathway for NF1, TSC and CS, and to hypoxia sensing for VHL. Phakomatoses share some phenotypic traits such as neurological, ophthalmological and cutaneous features. Patients with these diseases are also predisposed to developing multiple endocrine tissue tumors, e.g., pheochromocytomas/paragangliomas are frequent in VHL and NF1. All forms of phakomatoses except CS may be associated with digestive neuroendocrine tumors. More rarely, thyroid cancer and pituitary or parathyroid adenomas have been reported. These susceptibilities are noteworthy, because their occurrence rate, prognosis and management differ slightly from the sporadic forms. The aim of this review is to summarize current knowledge on endocrine glands tumors associated with VHL, NF1, TSC, and CS, especially neuroendocrine tumors and pheochromocytomas/paragangliomas. We particularly detail recent advances concerning prognosis and management, especially parenchyma-sparing surgery and medical targeted therapies such as mTOR, MEK and HIF-2 α inhibitors, which have shown truly encouraging results.

Clinical and Laboratory Characteristics of a Large Iranian Kindred Afflicted with Von Hippel Lindau Disease

BACKGROUND

Von Hippel Lindau (VHL) disease is a hereditary disorder characterized by the development of benign or malignant tumors in the brain, spinal cord, eyes, adrenal medulla, kidney, pancreas, and many other organs. Advances in molecular diagnosis have led to the identification of the affected members of families at earlier stages. We present the clinical, laboratory, and genetic characteristics of five generations of a large Iranian kindred with VHL.

METHODS

The proband, a 52-year-old Iranian man, was recognized with VHL. All family members underwent clinical, laboratory, imaging, and genetic evaluation. Medical files and histopathology reports of patients who had been operated on before were also reviewed. Diagnosis of the disease was based on clinical findings, positive family history of VHL, and development of a central nervous system or retinal hemangioblastoma or pheochromocytoma.

RESULTS

Based on diagnostic criteria, our initial evaluations revealed that 10 members of the family had already been affected by the disease. Among them, nine had pheochromocytoma, and one had retinal hemangioblastoma. There was no case of kidney tumors among the kindred.

CONCLUSIONS

Study results show the high penetrance of the disease and focus on the large burden imposed by the disease on the health and quality of life of patients afflicted with the disease, emphasizing the importance of surveillance from early childhood for detection and management of the disease as early as possible.

Ophthalmological Aspects of von-Hippel-Lindau Syndrome

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

What Have We Learned from Molecular Biology of Paragangliomas and Pheochromocytomas?

Recent advances in molecular genetics and genomics have led to increased understanding of the aetiopathogenesis of pheochromocytomas and paragangliomas (PPGLs). Thus, pan-genomic studies now provide a comprehensive integrated genomic analysis of PPGLs into distinct molecularly defined subtypes concordant with tumour genotypes. In addition, new embryological discoveries have refined the concept of how normal paraganglia develop, potentially establishing a developmental basis for genotype-phenotype correlations for PPGLs. The challenge for modern pathology is to translate these scientific discoveries into routine practice, which will be based largely on histopathology for the foreseeable future. Here, we review recent progress concerning the cell of origin and molecular pathogenesis of PPGLs, including pathogenetic mechanisms, genetic susceptibility and molecular classification. The current roles and tools of pathologists are considered from a histopathological perspective, including differential diagnoses, genotype-phenotype correlations and the use of immunohistochemistry in identifying hereditary predisposition and validating genetic variants of unknown significance. Current and potential molecular prognosticators are also presented with the hope that predictive molecular biomarkers will be integrated into risk stratification scoring systems to assess the metastatic potential of these intriguing neoplasms and identify potential drug targets.

VON HIPPEL-LINDAU DISEASE: Update on Pathogenesis and Systemic Aspects

PURPOSE

To provide an update summarizing the biologic pathways governing von Hippel-Lindau (VHL) disease pathogenesis and to provide an overview of systemic manifestations as well as screening recommendations.

METHODS

A PubMed search of the English language literature was reviewed using the following search terms: von Hippel-Lindau, von Hippel-Lindau disease, and VHL. Of 6,696 publications, the most current and pertinent information related to the pathogenesis and systemic aspects of VHL disease were included in this review.

RESULTS

von Hippel-Lindau disease is one of the most frequently occurring multisystem familial cancer syndromes. The disease results from germline mutation in the VHL tumor suppressor gene on the short arm of chromosome 3. Mutation in the VHL gene affects multiple cellular processes including transcriptional regulation, extracellular matrix formation, apoptosis, and, in particular, the cellular adaptive response to hypoxia. As a result, there is widespread development of vascular tumors affecting the retina, brain, and spine, as well as a spectrum of benign and malignant tumors and/or cysts in visceral organs.

CONCLUSION

The ophthalmologist plays a key role in VHL disease diagnosis, as retinal hemangioblastoma is frequently the first disease manifestation. Screening guidelines for individuals with known VHL disease, and those at risk of VHL disease, help to ensure early detection of potentially vision-threatening and life-threatening disease.

Targeting β2-Adrenergic Receptors Shows Therapeutical Benefits in Clear Cell Renal Cell Carcinoma from Von Hippel-Lindau Disease

Von Hippel–Lindau (VHL), is a rare autosomal dominant inherited cancer in which the lack of VHL protein triggers the development of multisystemic tumors such us retinal hemangioblastomas (HB), CNS-HB, and clear cell renal cell carcinoma (ccRCC). ccRCC ranks third in terms of incidence and first in cause of death. Standard systemic therapies for VHL-ccRCC have shown limited response, with recurrent surgeries being the only effective treatment. Targeting of β2-adrenergic receptor (ADRB) has shown therapeutic antitumor benefits on VHL-retinal HB (clinical trial) and VHL-CNS HB (in vitro). Therefore, the in vitro and in vivo antitumor benefits of propranolol (ADRB-1,2 antagonist) and ICI-118,551 (ADRB-2 antagonist) on VHL^−/− ccRCC primary cultures and 786-O tumor cell lines have been addressed. Propranolol and ICI-118,551 activated apoptosis inhibited gene and protein expression of HIF-2α, CAIX, and VEGF, and impaired partially the nuclear internalization of HIF-2α and NFĸB/p65. Moreover, propranolol and ICI-118,551 reduced tumor growth on two in vivo xenografts. Finally, ccRCC patients receiving propranolol as off-label treatment have shown a positive therapeutic response for two years on average. In summary, propranolol and ICI-118,551 have shown antitumor benefits in VHL-derived ccRCC, and since ccRCCs comprise 63% of the total RCCs, targeting ADRB2 becomes a promising drug for VHL and other non-VHL tumors.

Clinical diagnosis, treatment and screening of the VHL gene in three von Hippel-Lindau disease pedigrees

The present study aimed to investigate the clinical characteristics of von Hippel-Lindau (VHL) disease and the clinical significance of VHL gene detection. The clinical materials of patients with VHL disease were collected from 3 different families between May 1985 and October 2017. A systematic pedigree study and VHL gene detection at the germline level were performed together with a literature review. Of the 22 patients from 3 VHL pedigrees, 10 exhibited VHL gene mutations (3 genotypes) at the germline level. The genotypes of pedigree were VHL-p.R161Q (c.482G>A), VHL-p.N78S (c.233A>G), and VHL-p.R167Q (c.500G>A). During the follow-up period, the symptoms were stable in 10 patients, including 2 cases of central nervous system hemangioblastomas (CNS-HB), 3 cases of bilateral multiple renal cell carcinoma (RCC) and 5 cases of adrenal pheochromocytoma without local recurrence or distant metastasis. Patients with p.R161Q and p.N78S were not associated with CNS-HB, which was different from the clinical phenotype of previously reported families. RCC were Fuhrman II grade, which was consistent with the previous study. The results of the present study indicated that the standardization of early diagnosis and the improvement of long-term efficacy may be achieved by combining clinical screening and VHL gene detection.

Neuroendocrine Tumors of the Gastrointestinal Tract and Pancreas

Neuroendocrine neoplasms (NENs) of the gastrointestinal (GI) tract and pancreas are a rare and heterogeneous group of neoplasms characterized by common cellular features as well as unique site-specific traits. GI and pancreatic NENs are much rarer than the more common adenocarcinomas arising at these sites. However, the incidences of GI and pancreatic NENs have increased significantly, particularly in the stomach and common site, followed by rectum, appendix, colon, and stomach. Pancreatic NENs are also uncommon, with fewer than 1 per 100,000, accounting for 1% to 2% of all pancreatic neoplasms.

[Hereditary kidney cancers: The pathologist's view in 2020]

Hereditary predispositions to adult kidney tumors involve around 5% of tumors and include a dozen of autosomal dominant syndromes. The most frequent tumors encountered in these setting are clear cell renal cell carcinomas, papillary renal cell carcinomas, chromophobe renal cell carcinomas and angiomyolipomas. Their detection is essential in order to adapt individual care and perform genetic screening of at-risk relatives, especially in the national french network PREDIR, labeled by the National Cancer Institute and dedicated to hereditary predispositions to kidney tumors. Targeted genetic analysis, which was guided in particular by the renal tumor subtype, has recently evolved into genetic analysis using panels of genes. Pathologist contribution's remains however central in the diagnosis of hereditary forms since we currently have immunohistochemical biomarkers that allow us to diagnose two specifically hereditary entities: hereditary leiomyomatosis and renal cell carcinoma associated-renal cell carcinoma, associated with a loss of fumarate hydratase and succinate dehydrogenase-deficient renal cell carcinoma associated with a loss of succinate deshydrogenase B expression. These diagnoses must however be confirmed by the identification of pathogenic germline variation in the corresponding genes. Improvement of kidney tumors characterization has also lead to identify new subtypes, expanding the algorithm of renal tumors associated with hereditary setting. Here we aim to review all subtypes of adult renal tumors encountered in predisposition syndromes.

[Pathologist contribution in the diagnosis of hereditary predisposition to paranganglioma and pheochromocytoma]

Hereditary predispositions are responsible for more than 30% of or paraganglioma. Their identification is essential to optimize medical care and to offer an appropriate screening to relatives. To date, there are more than 15 known paraganglioma/pheochromocytoma predisposing genes. The most frequently involved are those encoding the succinate dehydrogenase (SDHx), accounting for half of cases and the VHL gene, causing the Von Hippel Lindau syndrome and representing approximately 20% of genetically determined cases. Patients with SDHB genes mutations have a higher risk of metastatic disease. An oncogenetic counseling is recommended to all patients developing one or several paragangliomas, isolated or associated with other tumors. Apart from the clinical presentation and in particular the syndromic forms characterized by specific tumor spectra, there is no validated morphological criterion allowing to suspect a hereditary form. On the other hand, pathologists have now access to several immunohistochemical tools allowing the identification of some hereditary forms, in particular those linked to the SDHx, VHL and FH genes. Thus, the loss of expression in immunohistochemistry of the SDHB or FH proteins orientates respectively, towards SDHx and FH genes, while the membrane expression of carbonic anhydrase IX (CA-IX) is a sensitive and specific tool pointing towards a VHL anomaly. Other immunohistochemical markers are under evaluation. A systematic SDHB immunohistochemical staining is recommended on all paragangliomas/pheochromocytomas in order to allow an early detection of the most common hereditary forms and to contribute to the interpretation of the genetic results in these patients seen in oncogenetics consultation.

Identification of a new aggressive axis driven by ciliogenesis and absence of VDAC1-ΔC in clear cell Renal Cell Carcinoma patients

Rationale: Renal cell carcinoma (RCC) accounts for about 2% of all adult cancers, and clear cell RCC (ccRCC) is the most common RCC histologic subtype. A hallmark of ccRCC is the loss of the primary cilium, a cellular antenna that senses a wide variety of signals. Loss of this key organelle in ccRCC is associated with the loss of the von Hippel-Lindau protein (VHL). However, not all mechanisms of ciliopathy have been clearly elucidated. Methods: By using RCC4 renal cancer cells and patient samples, we examined the regulation of ciliogenesis via the presence or absence of the hypoxic form of the voltage-dependent anion channel (VDAC1-ΔC) and its impact on tumor aggressiveness. Three independent cohorts were analyzed. Cohort A was from PREDIR and included 12 patients with hereditary pVHL mutations and 22 sporadic patients presenting tumors with wild-type pVHL or mutated pVHL; Cohort B included tissue samples from 43 patients with non-metastatic ccRCC who had undergone surgery; and Cohort C was composed of 375 non-metastatic ccRCC tumor samples from The Cancer Genome Atlas (TCGA) and was used for validation. The presence of VDAC1-ΔC and legumain was determined by immunoblot. Transcriptional regulation of IFT20/GLI1 expression was evaluated by qPCR. Ciliogenesis was detected using both mouse anti-acetylated α-tubulin and rabbit polyclonal ARL13B antibodies for immunofluorescence. Results: Our study defines, for the first time, a group of ccRCC patients in which the hypoxia-cleaved form of VDAC1 (VDAC1-ΔC) induces resorption of the primary cilium in a Hypoxia-Inducible Factor-1 (HIF-1)-dependent manner. An additional novel group, in which the primary cilium is re-expressed or maintained, lacked VDAC1-ΔC yet maintained glycolysis, a signature of epithelial-mesenchymal transition (EMT) and more aggressive tumor progression, but was independent to VHL. Moreover, these patients were less sensitive to sunitinib, the first-line treatment for ccRCC, but were potentially suitable for immunotherapy, as indicated by the immunophenoscore and the presence of PDL1 expression. Conclusion: This study provides a new way to classify ccRCC patients and proposes potential therapeutic targets linked to metabolism and immunotherapy.

Novel gene mutation in von Hippel-Lindau disease - a report of two cases

BACKGROUND

Von Hippel-Lindau (VHL) syndrome is a familial autosomal dominant hereditary neoplastic disease caused by mutations in the VHL gene. Approximately 503 kinds of VHL gene mutations have been reported. Different types of mutations manifest various clinical phenotypes, from benign to malignant tumours or coexisting cysts. Thus, a gene mutation test is essential in the diagnosis of VHL syndrome.

CASE PRESENTATION

We reported two cases in which a novel mutation site in the c530-536delGACTGGA region in exon 3 of the VHL gene resulted in the development of VHL syndrome. According to the ACMG guidelines, this variation is pathogenic and consistent with autosomal dominant inheritance. This variation has not been reported anywhere in the databases or literature.

CONCLUSION

This report will add a new mutation site to VHL gene databases. The newly added gene mutation and its associated clinical phenotypes will help improve the accuracy of VHL diagnosis and benefit the community of VHL gene mutation carriers.

Pheochromocytomas and Paragangliomas

Pheochromocytomas are rare neuroendocrine tumors. Extra-adrenal lesions arising from the autonomic neural ganglia are termed paraganglioma. Clinical symptoms are common between the adrenal and extra-adrenal forms and are determined by excess secretion of catecholamines. Hypertension is a critical and often dramatic feature of pheochromocytoma/paraganglioma, and its most prevalent reported symptom. However, given the rare occurrence of this cancer, in patients undergoing screening for hypertension, the prevalence ranges from 0.1% to 0.6%. Still, patients frequently come to the attention of endocrinologist when pheochromocytoma/paraganglioma is suspected as a secondary cause of hypertension. This article summarizes current clinical approaches in patients with pheochromocytoma/paraganglioma.

A Guide to Pheochromocytomas and Paragangliomas

Pheochromocytomas and extra-adrenal paragangliomas are rare neuroendocrine neoplasms with characteristic histologic and immunohistochemical features. These tumors can arise in several anatomic locations, necessitating that their diagnostic recognition extends beyond the realm of endocrine disorders. A practical and reproducible risk stratification system for these tumors is still in development. In this rapidly evolving era of molecular medicine, it is essential for pathologists to equip themselves with a framework for understanding the classification of paragangliomas and pheochromocytomas and be informed of how they might advise their colleagues with regard to prognostication and appropriate follow-up.

Cell death-related molecules and biomarkers for renal cell carcinoma targeted therapy

Renal cell carcinoma (RCC) is not sensitive to conventional radio- and chemotherapies and is at least partially resistant to impairments in cell death-related signaling pathways. The hallmarks of RCC formation include diverse signaling pathways, such as maintenance of proliferation, cell death resistance, angiogenesis induction, immune destruction avoidance, and DNA repair. RCC diagnosed during the early stage has the possibility of cure with surgery. For metastatic RCC (mRCC), molecular targeted therapy, especially antiangiogenic therapy (e.g., tyrosine kinase inhibitors, TKIs, such as sunitinib), is one of the main partially effective therapeutics. Various forms of cell death that may be associated with the resistance to targeted therapy because of the crosstalk between targeted therapy and cell death resistance pathways were originally defined and differentiated into apoptosis, necroptosis, pyroptosis, ferroptosis and autophagic cell death based on cellular morphology. Particularly, as a new form of cell death, T cell-induced cell death by immune checkpoint inhibitors expands the treatment options beyond the current targeted therapy. Here, we provide an overview of cell death-related molecules and biomarkers for the progression, prognosis and treatment of mRCC by targeted therapy, with a focus on apoptosis and T cell-induced cell death, as well as other forms of cell death.

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

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

Resistance to targeted treatment of gastroenteropancreatic neuroendocrine tumors

The mammalian target of rapamycin (mTOR) is part of the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt)/mTOR signaling. The PI3K/Akt/mTOR pathway has a pivotal role in the oncogenesis of neuroendocrine tumors (NETs). In addition, vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) drive angiogenesis in NETs and therefore contributes to neuroendocrine tumor development. Hence, mTOR and angiogenesis inhibitors have been developed. Everolimus, a first-generation mTOR inhibitor, has shown significant survival benefit in advanced gastroenteropancreatic NETs. Sunitinib, a pan-tyrosine kinase inhibitor that targets the VEGF receptor, has proven to increase progression-free survival in advanced pancreatic NETs. Nevertheless, primary and acquired resistance to rapalogs and sunitinib has limited the clinical benefit for NET patients. Despite the identification of multiple molecular mechanisms of resistance, no predictive biomarker has made it to the clinic. This review is focused on the mTOR signaling and angiogenesis in NET, the molecular mechanisms of primary and acquired resistance to everolimus and sunitinib and how to overcome this resistance by alternative drug compounds.

Integrative analysis of dysregulated microRNAs and mRNAs in multiple recurrent synchronized renal tumors from patients with von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease is a rare auto-somal dominant syndrome that is the main cause of inherited clear-cell renal cell carcinoma (ccRCC), which generally occurs in the form of multiple recurrent synchronized tumors. Affected patients are carriers of a germline mutation in the VHL tumor suppressor gene. Somatic mutations of this gene are also found in sporadic ccRCC and numerous pan-genomic studies have reported a dysregulation of microRNA (miRNA) expression in these sporadic tumors. In order to investigate the molecular mechanisms underlying the pathogenesis of VHL-associated ccRCC, particularly in the context of multiple tumors, the present study characterized the mRNA and miRNA transcriptome through an integrative analysis compared with sporadic renal tumors. In the present study, two series of ccRCC samples were used. The first set consisted of several samples from different tumors occurring in the same patient, for two independent patients affected with VHL disease. The second set consisted of 12 VHL-associated tumors and 22 sporadic ccRCC tumors compared with a pool of normal renal tissue. For each sample series, an expression analysis of miRNAs and mRNAs was conducted using microarrays. The results indicated that multiple tumors within the kidney of a patient with VHL disease featured a similar pattern of miRNA and gene expression. In addition, the expression levels of miRNA were able to distinguish VHL-associated tumors from sporadic ccRCC, and it was identified that 103 miRNAs and 2,474 genes were differentially expressed in the ccRCC series compared with in normal renal tissue. The majority of dysregulated genes were implicated in 'immunity' and 'metabolism' pathways. Taken together, these results allow a better understanding of the occurrence of ccRCC in patients with VHL disease, by providing insights into dysregulated miRNA and mRNA. In the set of patients with VHL disease, there were few differences in miRNA and mRNA expression, thus indicating a similar molecular evolution of these synchronous tumors and suggesting that the same molecular mechanisms underlie the pathogenesis of these hereditary tumors.

Identification of a new VHL exon and complex splicing alterations in familial erythrocytosis or von Hippel-Lindau disease

Chuvash polycythemia is an autosomal recessive form of erythrocytosis associated with a homozygous p.Arg200Trp mutation in the von Hippel-Lindau (VHL) gene. Since this discovery, additional VHL mutations have been identified in patients with congenital erythrocytosis, in a homozygous or compound-heterozygous state. VHL is a major tumor suppressor gene, mutations in which were first described in patients presenting with VHL disease, which is characterized by the development of highly vascularized tumors. Here, we identify a new VHL cryptic exon (termed E1') deep in intron 1 that is naturally expressed in many tissues. More importantly, we identify mutations in E1' in 7 families with erythrocytosis (1 homozygous case and 6 compound-heterozygous cases with a mutation in E1' in addition to a mutation in VHL coding sequences) and in 1 large family with typical VHL disease but without any alteration in the other VHL exons. In this study, we show that the mutations induced a dysregulation of VHL splicing with excessive retention of E1' and were associated with a downregulation of VHL protein expression. In addition, we demonstrate a pathogenic role for synonymous mutations in VHL exon 2 that altered splicing through E2-skipping in 5 families with erythrocytosis or VHL disease. In all the studied cases, the mutations differentially affected splicing, correlating with phenotype severity. This study demonstrates that cryptic exon retention and exon skipping are new VHL alterations and reveals a novel complex splicing regulation of the VHL gene. These findings open new avenues for diagnosis and research regarding the VHL-related hypoxia-signaling pathway.

Renal cell carcinoma drug and cell therapy: today and tomorrow

Today, considerable progress in the renal cell carcinoma (RCC) treatment has been made due to development of targeted and immunotherapeutic approaches to the RCC treatment, especially in metastasising carcinoma. In the early stages of RCC, it is possible to use partial or total surgical nephrectomy, but in metastases development, the range of efficient treatment methods is dramatically limited. Appearance of targeted drugs like PD-1 and CTLA-4 receptors and their ligands’ inhibitors in clinical practice has significantly increased the total survival rate of patients with renal cell carcinoma. Emergence of adoptive cell therapy has opened new possibilities and prospects in RCC treatment. Previously activated in vitro cells are used there, which provides antineoplastic activity. For example, it could be antigen-specific cytotoxic T-lymphocytes (CTL), lymphokine-activated natural killers (LAK-NK-cells) and tumour-infiltrating lymphocytes (TILs). In this review, the authors specified the main molecular markers, associated with RCC; and signalling pathways (VEGFR- and EGFR-signalling pathway), which directly take part in carcinogenesis. The paper also looks at clinically applicable targeted immune drugs and the principle of their effect on tumorous cells. Besides, modern clinical studies of cell drugs have been considered. At the moment, there are a number of variants of targeted and immune drugs for the metastatic RCC treatment. Patients have no opportunity to use all the available agents because of their cost and toxicity level. For the most efficient treatment of patients with diagnosed metastatic RCC, it is necessarily to carry out risk stratification and prognostic factors for the response to treatment.

Metabolic Pathways of the Warburg Effect in Health and Disease: Perspectives of Choice, Chain or Chance

Focus on the Warburg effect, initially descriptive of increased glycolysis in cancer cells, has served to illuminate mitochondrial function in many other pathologies. This review explores our current understanding of the Warburg effect’s role in cancer, diabetes and ageing. We highlight how it can be regulated through a chain of oncogenic events, as a chosen response to impaired glucose metabolism or by chance acquisition of genetic changes associated with ageing. Such chain, choice or chance perspectives can be extended to help understand neurodegeneration, such as Alzheimer’s disease, providing clues with scope for therapeutic intervention. It is anticipated that exploration of Warburg effect pathways in extreme conditions, such as deep space, will provide further insights crucial for comprehending complex metabolic diseases, a frontier for medicine that remains equally significant for humanity in space and on earth.

Specific Localization of Missense Mutations in the VHL Gene in Clear Cell Renal Cell Carcinoma

Missense mutations in the VHL gene during sporadic clear cell renal cell carcinoma were studied to evaluate their localization in relation to functionally important motifs of the VHL protein. Somatic mutations were identified in 124 of 307 samples. All missense mutations in the α-domain were localized in the binding site for elongin C. Substitutions in the β-domain (77%) were found in the HIF-binding site. Five missense mutations were absent in these sites, which illustrates their role in VHL protein formation or suppressor function of other protein cofactors. Mutation c.392A→T (p.N131I) was identified for the first time. Our results hold much promise to estimate the boundaries of functionally important sites in the VHL suppressor gene and contribute to the interpretation of a pathogenic role of mutations in direct DNA diagnostics.

Radiofrequency Ablation for Renal Cancer in Von Hippel-Lindau Syndrome Patients: A Prospective Cohort Analysis

INTRODUCTION

Management of renal-cell carcinoma (RCC) in patients with Von Hippel-Lindau syndrome (VHL) represents a clinical dilemma: the oncologic outcomes must be weighed against preservation of renal function. Radiofrequency ablation (RFA) is currently used in selected cases for treatment of small-size RCC. The aim of this study was to evaluate the safety, complications, and functional and oncologic outcomes of RFA in the treatment of RCC in VHL patients.

PATIENTS AND METHODS

RCCs were treated with ultrasound-guided RFA or with laparoscopic RFA. Clinical and radiologic response, disease recurrence, and survival outcomes were evaluated during follow-up. Early and late complications were recorded and graded.

RESULTS

Nine RCC patients underwent RFA. The median number of RCCs per patient was 3 (interquartile range, 2-4). Among these 9 patients, a total of 20 RCCs were treated by RFA (19 ultrasound-guided RFA and 1 laparoscopic procedure). Median RCC size was 2.5 cm (interquartile range, 2.0-3.0). RFA did not impair renal function (P = .35). In 2 cases disease persisted, and in 1 case disease recurred after 18 months. These patients were retreated with ultrasound-guided RFA with complete response and no renal function impairment. RFA treatment was overall well tolerated and safe. No complications were recorded. Postoperative stay was no longer than 1 day.

CONCLUSION

RCC occurred in about two-thirds of VHL patients, who had young age at presentation; it was frequently multifocal and recurrent. The use of RFA, with extended indications, could represent a tailored treatment for VHL patients, reducing the risk of renal failure and resulting in satisfying oncologic results.

Repurposing propranolol as a drug for the treatment of retinal haemangioblastomas in von Hippel-Lindau disease

BACKGROUND

Von Hippel-Lindau (VHL) disease is a rare oncological disease with an incidence of 1:36,000, and is characterized by the growth of different types of tumours. Haemangioblastomas in the central nervous system (CNS) and retina, renal carcinoma and pheochromocytomas are the most common tumours. The absence of treatment for VHL leads to the need of repeated surgeries as the only option for these patients. Targeting VHL-derived tumours with drugs with reduced side effects is urgent to avoid repeated CNS surgeries. Recent reports have demonstrated that propranolol, a β-blocker used for the treatment of hypertension and other cardiac and neurological diseases, is the best option for infantile hemangioma (IH). Propranolol could be an efficient treatment to control haemangioblastoma growth in VHL disease given its antiangiogenic effects that were recently demonstrated by us. The main objective of the present study was the assessment of the efficacy and safety of propranolol on retinal haemangioblastoma in von Hippel-Lindau disease (VHL).

METHODS

7 VHL patients, from different regions of Spain, affected from juxtapapillary or peripheral haemangioblastomas were administered 120 mg propranolol daily. Patients were evaluated every 3 months for 12 months, at Virgen de la Salud Hospital (Toledo). The patients had juxtapapillary or peripheral haemangioblastomas but had refused standard treatments.

RESULTS

Propranolol was initiated with a progressive increase up to a final dose of 120 mg daily. All tumours remained stable, and no new tumours appeared. The reabsorption of retinal exudation was noted in the two patients having exudates. No adverse effects were recorded. VEGF and miRNA 210 levels were monitored in the plasma of patients as possible biomarkers of VHL. These levels decreased in all cases from the first month of treatment.

CONCLUSIONS

Although more studies are necessary, the results of this work suggest that propranolol is a drug to be considered in the treatment of VHL patients with retinal haemangioblastomas. VEGF and miRNA 210 could be used as biomarkers of the VHL disease activity.

TRIAL REGISTRATION

The study has a clinical trial design and was registered at EU Clinical Trials Register and Spanish Clinical Studies Registry, EudraCT Number: 2014-003671-30 . Registered 2 September 2014.

Hereditary Renal Tumor Syndromes: Update on Diagnosis and Management

Hereditary renal cancers account for approximately 5%-8% of all renal tumors. Over the past 2 decades, a number of syndromes have been identified that predispose patients to early renal cancer development, representing all the major histologic types of tumor pathology. In this article, we describe the current knowledge concerning the cell type, known mechanism of tumor development, other manifestations of the syndrome, imaging findings, genetic screening, and imaging surveillance recommendations for each of the major syndromes associated with hereditary renal cancers.

Renal Cell Carcinoma Programmed Death-ligand 1, a New Direct Target of Hypoxia-inducible Factor-2 Alpha, is Regulated by von Hippel-Lindau Gene Mutation Status

BACKGROUND

Clear cell renal cell carcinomas (ccRCC) frequently display a loss of function of the von Hippel-Lindau (VHL) gene.

OBJECTIVE

To elucidate the putative relationship between VHL mutation status and immune checkpoint ligand programmed death-ligand 1 (PD-L1) expression.

DESIGN, SETTING, AND PARTICIPANTS

A series of 32 renal tumors composed of 11 VHL tumor-associated and 21 sporadic RCCs were used to evaluate PD-L1 expression levels after sequencing of the three exons and exon-intron junctions of the VHL gene. The 786-O, A498, and RCC4 cell lines were used to investigate the mechanisms of PD-L1 regulation.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Fisher's exact test was used for VHL mutation and Kruskal-Wallis test for PD-L1 expression. If no covariate accounted for the association of VHL and PD-L1, then a Kruskal-Wallis test was used; otherwise Cochran-Mantel-Haenzsel test was used. We also used the Fligner-Policello test to compare two medians when the distributions had different dispersions.

RESULTS AND LIMITATIONS

We demonstrated that tumors from ccRCC patients with VHL biallelic inactivation (ie, loss of function) display a significant increase in PD-L1 expression compared with ccRCC tumors carrying one VHL wild-type allele. Using the inducible VHL 786-O-derived cell lines with varying hypoxia-inducible factor-2 alpha (HIF-2α) stabilization levels, we showed that PD-L1 expression levels positively correlate with VHL mutation and HIF-2α expression. Targeting HIF-2α decreased PD-L1, while HIF-2α overexpression increased PD-L1 mRNA and protein levels in ccRCC cells. Interestingly, chromatin immunoprecipitation and luciferase assays revealed a direct binding of HIF-2α to a transcriptionally active hypoxia-response element in the human PD-L1 proximal promoter in 786-O cells.

CONCLUSIONS

Our work provides the first evidence that VHL mutations positively correlate with PD-L1 expression in ccRCC and may influence the response to ccRCC anti-PD-L1/PD-1 immunotherapy.

PATIENT SUMMARY

We investigated the relationship between von Hippel-Lindau mutations and programmed death-ligand 1 expression. We demonstrated that von Hippel-Lindau mutation status significantly correlated with programmed death-ligand 1 expression in clear cell renal cell carcinomas.

VHL Germline Mutations in Argentinian Patients with Clinical Diagnoses or Single Typical Manifestations of Type 1 von Hippel-Lindau Disease

AIMS

von Hippel-Lindau (VHL) disease is caused by mutations in the VHL tumor suppressor gene. As tumors that develop in the context of VHL also occur in a sporadic context, the frequency of this syndrome may be underestimated. Our aim was to identify VHL gene mutations in Argentinian patients who fulfilled the clinical criteria for type 1 VHL disease and in patients with VHL-associated manifestations that did not meet these criteria.

METHODS

We performed a retrospective cohort study, including patients who met current diagnostic criteria for type 1 VHL (Group 1, n = 19) and patients with VHL-associated manifestations that did not meet these criteria (Group 2, n = 21). Genomic DNA was extracted from peripheral blood leukocytes. Mutation analysis involved DNA sequencing, while large deletions were determined by universal primer quantitative fluorescent multiplex polymerase chain reaction (UPQFM-PCR) and multiplex ligation-dependent probe amplification (MLPA) analysis.

RESULTS

VHL mutations were detected in 16/19 (84.2%) patients in Group 1 and included: gross deletions (4/16); nonsense mutations (6/16); frameshift mutations (4/16); missense mutations (1/16); and splicing mutations (1/16). Three of these mutations were novel. No alterations were found in 3 of 19 VHL patients. In Group 2, one nonsense VHL mutation was detected in a young patient with a solitary central nervous system hemangioblastoma without familial history. A study of 30 first-degree relatives revealed four carriers with VHL mutations.

CONCLUSIONS

We found three novel mutations in the VHL gene in our population. Our results emphasize the importance of a complete genetic study of VHL to confirm type 1 VHL disease, not only in patients with clinical diagnostic criteria but also in those presenting a single typical manifestation.

Neurological Management of Von Hippel-Lindau Disease

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

The Nephrologist's Tumor: Basic Biology and Management of Renal Cell Carcinoma

Kidney cancer, or renal cell carcinoma (RCC), is a disease of increasing incidence that is commonly seen in the general practice of nephrology. However, RCC is under-recognized by the nephrology community, such that its presence in curricula and research by this group is lacking. In the most common form of RCC, clear cell renal cell carcinoma (ccRCC), inactivation of the von Hippel-Lindau tumor suppressor is nearly universal; thus, the biology of ccRCC is characterized by activation of hypoxia-relevant pathways that lead to the associated paraneoplastic syndromes. Therefore, RCC is labeled the internist's tumor. In light of this characterization and multiple other metabolic abnormalities recently associated with ccRCC, it can now be viewed as a metabolic disease. In this review, we discuss the basic biology, pathology, and approaches for treatment of RCC. It is important to distinguish between kidney confinement and distant spread of RCC, because this difference affects diagnostic and therapeutic approaches and patient survival, and it is important to recognize the key interplay between RCC, RCC therapy, and CKD. Better understanding of all aspects of this disease will lead to optimal patient care and more recognition of an increasingly prevalent nephrologic disease, which we now appropriately label the nephrologist's tumor.

Genetic associations with neuroendocrine tumor risk: results from a genome-wide association study

The etiology of neuroendocrine tumors remains poorly defined. Although neuroendocrine tumors are in some cases associated with inherited genetic syndromes, such syndromes are rare. The majority of neuroendocrine tumors are thought to be sporadic. We performed a genome-wide association study (GWAS) to identify potential genetic risk factors for sporadic neuroendocrine tumors. Using germline DNA from blood specimens, we genotyped 909,622 SNPs using the Affymetrix 6.0 GeneChip, in a cohort comprising 832 neuroendocrine tumor cases from Dana-Farber Cancer Institute and Massachusetts General Hospital and 4542 controls from the Harvard School of Public Health. An additional 241 controls from Dana-Farber Cancer Institute were used for quality control. We assessed risk associations in the overall cohort, and in neuroendocrine tumor subgroups. We identified no potential risk associations in the cohort overall. In the small intestine neuroendocrine tumor subgroup, comprising 293 cases, we identified risk associations with three SNPs on chromosome 12, all in strong LD. The three SNPs are located upstream of ELK3, a transcription factor implicated in angiogenesis. We did not identify clear risk associations in the bronchial or pancreatic neuroendocrine subgroups. This large-scale study provides initial evidence that presumed sporadic small intestine neuroendocrine tumors may have a genetic etiology. Our results provide a basis for further exploring the role of genes implicated in this analysis, and for replication studies to confirm the observed associations. Additional studies to evaluate potential genetic risk factors for sporadic pancreatic and bronchial neuroendocrine tumors are warranted.

Neovascularity as a prognostic marker in renal cell carcinoma

Endothelial markers platelet and endothelial cell adhesion molecule (PECAM-1), cluster of differentiation (CD31) and endoglin (CD105) may be used to identify endothelium and activated endothelium, respectively, with the CD105/CD31 ratio used to measure neovascularity. This study investigated the hypothesis that neovascularity in renal cell carcinoma (RCC) is associated with more aggressive RCC tumors and can be used to predict oncological outcomes. Multiplexed immunohistochemistry using antibodies to detect endoglin and PECAM-1 was performed on tissue microarray of benign kidney samples and RCC tumors including clear cell, papillary, chromophobe, and collecting duct and unclassified tumors (combined for statistics), and multispectral imaging was used for analysis. The CD105/CD31 ratio was compared with clinical and pathologic features of RCC as well as clinical outcomes after surgery using Cox proportional hazards regression and Kaplan-Meier analysis. A total of 502 tumor samples and 122 normal kidney samples from 251 RCC patients were analyzed. The average CD105/CD31 expression ratio, an indicator of neovascularization, was increased in higher pathologic stage tumors (P< .0001). Among RCC morphotypes, the ratio was lower in papillary RCC morphotype tumors (P= .001) and higher in collecting duct/unclassified tumors (P= .0001) compared with clear cell RCC. Among nuclear grades, grade 4 RCC displayed a significantly elevated CD105/CD31 ratio (P< .0001). In multivariable analysis, increased neovascularity was associated with decreased overall survival (hazard ratio, 1.54 [95% confidence interval, 1.06-2.23]; P= .02). In patients receiving anti-vascular endothelial growth factor therapy (VEGF, n = 13) for metastatic RCC, a low CD105/CD31 ratio was associated with increased survival (P= .02). We conclude that higher neovascularity is associated with worse outcomes after surgery for RCC. The ratio of CD105/CD31 expression is a potential indicator of response to anti-VEGF therapy.

Inherited renal carcinomas

Hereditary forms of kidney carcinoma account for 5-8% of all malignant kidney neoplasms. The renal tumors are often multiple and bilateral and occur at an earlier age. Each of the hereditary kidney carcinoma syndromes is associated with specific gene mutations as well as a specific histologic type of kidney carcinoma. The presence of associated extrarenal manifestations may suggest a hereditary kidney cancer syndrome. Radiology is most commonly used to screen and manage patients with hereditary kidney cancer syndromes. This manuscript reviews the clinical and imaging findings of well-defined inherited kidney cancer syndromes including von Hippel-Lindau disease, Birt-Hogg-Dubé syndrome, hereditary papillary renal carcinoma syndrome, hereditary leiomyomatosis and RCC syndrome, tuberous sclerosis complex, and Lynch syndrome.

Aggregation dynamics and identification of aggregation-prone mutants of the von Hippel-Lindau tumor suppressor protein

Quality control mechanisms promote aggregation and degradation of misfolded proteins. In budding yeast, the human von Hippel-Lindau protein (pVHL, officially known as VHL) is misfolded and forms aggregates. Here, we investigated the aggregation of three pVHL isoforms (pVHL213, pVHL160, pVHL172) in fission yeast. The full-length pVHL213 isoform aggregates in highly dynamic small puncta and in large spherical inclusions, either close to the nucleus or to the cell ends. The large inclusions contain the yeast Hsp104 chaperone. Aggregate clearance is regulated by proteasomal degradation. The pVHL160 isoform forms dense foci and large irregularly shaped aggregates. In silico, prediction of pVHL aggregation propensity identified a key aggregation-promoting region within exon 2. Consistently, the pVHL172 isoform, which lacks exon 2, formed rare reduced inclusions. We studied the aggregation propensity of pVHL variants harbouring missense mutations found in kidney carcinomas. We show that the P86L mutation stimulated small aggregate formation, the P146A mutation increased large inclusion formation, whereas the I151S mutant destabilized pVHL. The prefoldin subunit Pac10 (the human homolog VBP-1 binds to pVHL) is required for pVHL stability. Reduction of soluble functional pVHL might be crucial in VHL-related diseases.