The von Hippel-Lindau gene: turning discovery into therapy

Immunogenicity in renal cell carcinoma: shifting focus to alternative sources of tumour-specific antigens

Renal cell carcinoma (RCC) comprises a group of malignancies arising from the kidney with unique tumour-specific antigen (TSA) signatures that can trigger cytotoxic immunity. Two classes of TSAs are now considered potential drivers of immunogenicity in RCC: small-scale insertions and deletions (INDELs) that result in coding frameshift mutations, and activation of human endogenous retroviruses. The presence of neoantigen-specific T cells is a hallmark of solid tumours with a high mutagenic burden, which typically have abundant TSAs owing to non-synonymous single nucleotide variations within the genome. However, RCC exhibits high cytotoxic T cell reactivity despite only having an intermediate non-synonymous single nucleotide variation mutational burden. Instead, RCC tumours have a high pan-cancer proportion of INDEL frameshift mutations, and coding frameshift INDELs are associated with high immunogenicity. Moreover, cytotoxic T cells in RCC subtypes seem to recognize tumour-specific endogenous retrovirus epitopes, whose presence is associated with clinical responses to immune checkpoint blockade therapy. Here, we review the distinct molecular landscapes in RCC that promote immunogenic responses, discuss clinical opportunities for discovery of biomarkers that can inform therapeutic immune checkpoint blockade strategies, and identify gaps in knowledge for future investigations.

Belzutifan: A Narrative Drug Review

Von Hippel-Lindau disease is an autosomal dominant disorder characterised by renal cell carcinomas, pancreatic neuroendocrine tumours, central nervous system hemangioblastomas, retinoblastomas, and tumours of the reproductive tract. This disease results from loss of function mutations in the tumour suppressor gene known as the Von Hippel-Lindau gene, located on chromosome 3. Loss of function mutation in the Von Hippel-Lindau gene results in the accumulation of a protein known as a hypoxia-inducible factor, which promotes cellular proliferation and angiogenesis, leading to cancer. Belzutifan inhibits the hypoxia-inducible factor by binding to the Per-ARNT -Sim-B binding pocket on the hypoxia-inducible factor -2α, inhibiting cellular proliferation and angiogenesis. In our thorough literature review, we identified 37 relevant articles. Belzutifan showed clinically meaningful response rates for both Von Hippel-Lindau disease-associated renal cell carcinomas and non-renal cell cancers. The pharmacokinetic profile of belzutifan was much better than its congener molecules due to the optimisation of its dihalide groups from germinal to vicinal. The pharmacodynamic effect of belzutifan was confirmed by its ability to decrease serum erythropoietin, which is a direct result of hypoxia-inducible factor- 2α inhibition. The significant side effects observed were anaemia, hypoxia, fatigue, hypertension, visual impairment and weight gain. Multiple clinical trials are currently underway to determine the role of beluztifan as part of combination regimens in treating Von Hippel-Lindau disease-associated malignancies.

VHL-P138R and VHL-L163R Novel Variants: Mechanisms of VHL Pathogenicity Involving HIF-Dependent and HIF-Independent Actions

The von Hippel-Lindau (VHL) disease is an autosomal dominant cancer syndrome caused by mutations in the VHL tumor suppressor gene. VHL protein (pVHL) forms a complex (VBC) with Elongins B-C, Cullin2, and Rbx1. Although other functions have been discovered, the most described function of pVHL is to recognize and target hypoxia-inducible factor (HIF) for degradation. This work comprises the functional characterization of two novel variants of the VHL gene (P138R and L163R) that have been described in our center in patients with VHL disease by in vitro, in vivo, and in silico approaches. In vitro, we found that these variants have a significantly shorter half-life compared to wild-type VHL but still form a functional VBC complex. Altered fibronectin deposition was evidenced for both variants using immunofluorescence. In vivo studies revealed that both variants failed to suppress tumor growth. By means of molecular dynamics simulations, we inspected in silico the nature of the changes introduced by each variant in the VBC complex. We have demonstrated the pathogenicity of P138R and L163R novel variants, involving HIF-dependent and HIF-independent mechanisms. These results provide the basis for future studies regarding the impact of structural alterations on posttranslational modifications that drive pVHL's fate and functions.

The importance of genetic study and long-term management in patients with bilateral pheochromocytomas

Tumors secreting catecholamines, such as pheochromocytomas and paragangliomas, are rare and life-threatening, due to their complications. They can be sporadic or occur in genetic syndromes, such as von Hippel-Lindau in which pheochromocytomas are observed in 10 to 20%. We report a case of a 42 years old male, who was sent in 2016 to our department for neurological symptoms related to cerebellar and central vestibular syndromes. His medical history revealed that at 8 years old he was operated for a symptomatic bilateral pheochromocytoma discovered by adrenergic symptoms and high blood pressure. Cerebral MRI showed intra- and extra-axial, supra- and infratentorial lesions causing supratentorial hydrocephalus associated with leptomeningeal dissemination deemed to be hemangioblastomas. One year later the patient started complaining of chronic diarrhea. The abdominal CT revealed three pancreatic tumors with radiological signs of pancreatic neuroendocrine tumors (PNETs) and a 12 mm mesenteric nodule presenting as a homogenously and typical for NET. The largest PNET had intensive fixation on octreotide scintigraphy. The association of pheochromocytomas, hemangioblastoma and pancreatic neuroendocrine tumors highlighted the diagnosis of VHL syndrome. The family history proved positive in a sibling with bilateral pheochromocytoma in infancy, retinal hemangioblastomas and cerebral hemangioblastoma. Genetic testing would have been useful, but in our case, it was lacking due to poor socio-economic conditions of the patient and absence of genetic testing in public hospitals.

Renal Lipid Metabolism Abnormalities in Obesity and Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma is the most common and deadly type of cancer affecting the kidney, and is characterized histologically by large intracellular lipid deposits. These deposits are thought to result from lipid metabolic reprogramming occurring in tumor cells, but the exact mechanisms and implications of these metabolic alterations are incompletely understood. Obesity is an independent risk factor for clear cell renal cell carcinoma, and is also associated with lipid accumulation in noncancerous epithelial cells of the proximal tubule, where clear cell renal cell carcinoma originates. This article explores the potential link between obesity-associated renal lipid metabolic disturbances and lipid metabolic reprogramming in clear cell renal cell carcinoma, and discusses potential implications for future research.

Mutations in renal cell carcinoma

Renal cell carcinoma (RCC) is a commonly diagnosed and histologically diverse urologic malignancy. Clear cell RCC (ccRCC) is by far the most common, followed by the papillary and chromophobe subtypes. Sarcomatoid differentiation is a morphologic change that can be seen in all subtypes that typically portends a poor prognosis. In the past, treatment options for RCC were limited to cytokine-based therapy with a high-toxicity profile and low response rate. An increased understanding of the molecular basis of RCC has led to substantial improvement in treatment options in the form of targeted therapy and immunotherapy. A significant early discovery in RCC was frequent inactivation of the Von Hippel Lindau gene in ccRCC, which ultimately led to the development of vascular endothelial growth factor and mammalian target of rapamycin inhibitors. Further genomic sequencing of ccRCC tumors has identified other common mutations including BAP-1, PBRM1, SETD2, and PIK3CA. Many recent studies have explored how these mutations can affect prognosis and response to treatment. Likewise, papillary RCC has also been studied at the molecular level, which has shown a high level of mutations in the MET gene; early clinical data suggest the utility of MET targeted therapy. Finally, regarding the rarer sarcomatoid tumors, mutations in TP53 and NF2 may be important to their development. As we continue to learn more about what drives RCC at the molecular level, treatment options for RCC patients are diversifying.

Extraneuraxial Hemangioblastoma: Clinicopathologic Features and Review of the Literature

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

A case of 3p deletion syndrome associated with cerebellar hemangioblastoma

We described clinical course of a 24-year-old woman with 3p deletion syndrome associated with cerebellar hemangioblastoma at the age of 16 years old. She presented dysmorphic facial features, growth retardation and severe psychomotor retardation associated with 3p deletion syndrome. We identified de novo 3p deletion encompassing p25 by using array-based comparative genomic hybridization, where causative gene of von Hippel-Lindau (VHL) disease located. Surgical therapy for cerebellar hemangioblastoma was performed, and histological examination was consistent in cerebellar hemangioblastoma. She showed no other tumors associated VHL disease till 24 years old. This is the first case report of a patient with 3p deletion syndrome whose cerebellar hemangioblastoma may be associated with VHL disease. Repeat imaging studies were recommended for the patients with 3p deletion syndrome.

The von Hippel-Lindau tumour suppressor gene: uncovering the expression of the pVHL172 isoform

BACKGROUND

The von Hippel-Lindau (VHL) gene encodes two mRNA variants. Variant 1 encodes two protein isoforms, pVHL213 and pVHL160, that have been extensively documented in the literature. Variant 2 is produced by alternative splicing of exon 2 and encodes a pVHL isoform of 172 amino acids with a theoretical molecular weight of 19 kDa (pVHL172), the expression of which has never been demonstrated so far due to the absence of suitable antibodies.

METHODS

We have generated an anti-pVHL monoclonal antibody (JD-1956) using pVHL172 recombinant protein. We tested the antibody against exogenous or endogenous expressed proteins in different cell lines. We identified the pVHL172 using a silencing RNA strategy. The epitope of the antibody was mapped using a peptide array.

RESULTS

We efficiently detected the three different isoforms of pVHL in cell lines and tumorigenic tissues by western blotting and immunohistochemistry and confirmed for the first time the endogenous expression of pVHL172.

CONCLUSIONS

The endogenous expression of the three isoforms and particularly the pVHL172 has never been shown before due to a lack of a highly specific antibody since none of the available commercial antibodies distinguish the three isoforms of pVHL in cells or in both normal and cancerous human tissues. Evidence of pVHL172 expression emphasises the need to further study its implication in renal tumorigenesis and VHL disease.

Antitumor effect and biological pathways of a recombinant adeno-associated virus as a human renal cell carcinoma suppressor

The aims of this work are to study the antitumor effect of the adeno-associated virus on the xenografted tumors of chick embryo chorioallantoic membrane and predict potential genes and biological pathways which are associated with renal cell carcinoma. The adeno-associated virus NT4-TAT-6 × His-VHLbeta was constructed and identified. Then, chick embryos with xenografted tumor were divided into three groups and respectively inoculated with rAAV/NT4-TAT-6 × His-VHLbeta (group A), empty virus (group B), and phosphate-buffered saline (group C, the control subject). Antitumor effect in each group was investigated by means of immunofluorescence observation. Genes interacted with von Hippel–Lindau were screened by Search Tool for the Retrieval of Interacting Genes/Proteins database, while pathway analysis were performed based on Kyoto Encyclopedia of Genes and Genomes. The growth of xenografted tumors inoculated with recombinant adeno-associated virus was slower than the control subjects. The tumor volumes of group A showed significant difference compared with group B and group C (P < 0.05). Growth of xenografted tumors which administered with the recombinant adeno-associated virus was inhibited. Among the protein–protein interaction network, TCEB2, HIF1A, TCEB1, CUL2, RBX1, and PHF17 were hub genes which might be involved in the development of renal cell carcinoma. The most significant signaling pathway was renal cell carcinoma. In this paper, we constructed and identified the recombinant adeno-associated virus NT4-TAT-6 × His-VHLbeta and studied the antitumor effect of the adeno-associated virus on xenografted tumors of chicken embryo chorioallantoic membrane. In addition, genes in the protein–protein interaction network which are associated with renal cell carcinoma were revealed and the biological pathway of renal cell carcinoma was identified. Our results provide a gene-therapeutic agent for the treatment of human renal cell carcinoma.

Obstructive jaundice due to von Hippel-Lindau disease-associated pancreatic lesions: A case report

von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited neoplastic syndrome that may lead to pancreatic masses and obstructive jaundice. The present study describes the case of a 20-year-old male who suffered from obstructive jaundice due to VHL disease-associated pancreatic lesions whose primary symptom was dizziness, followed by the appearance of jaundice. Since the excision of the renal cell carcinomas was not possible, the patient also refused surgery to resect the pancreatic head mass. A metallic stent was placed at the stenosis site of the common bile duct. Percutaneous transhepatic cholangiography (PTCD) surgery was later performed following complete blockage of the stent, however, to date, the patient continues to rely on PTCD. VHL disease-associated pancreatic lesions are rarely the direct cause of mortality, however, obstructive jaundice due to these lesions may be lethal. Therefore, the treatment of patients with incurable renal or central nervous system tumors and obstructive jaundice presents a problem.

Hereditary syndromes with associated renal neoplasia: a practical guide to histologic recognition in renal tumor resection specimens

Many hereditary tumor syndromes are associated with neoplasms of the kidney. It is becoming increasingly well recognized that a given familial tumor syndrome may be very heterogenous in clinical appearance and that unrecognized patients may present initially for the treatment of a renal mass. It is therefore important for surgical pathologists to be aware of the specific gross and microscopic findings in the kidney that suggest a possible syndromic association. In this review, we detail the histologic features of syndromic-associated renal neoplasms, describe the presence of characteristic changes in the background renal parenchyma, and provide an update on associated extrarenal manifestations for each of the following syndromes: von Hippel-Lindau disease, hereditary papillary renal cell carcinoma (RCC), hereditary leiomyomatosis-RCC, Birt-Hogg-Dubé syndrome, tuberous sclerosis complex, germline succinate dehydrogenase mutation, hereditary nonpolyposis colorectal cancer syndrome, hyperparathyroidism-jaw tumor syndrome, PTEN hamartoma syndrome, constitutional chromosome 3 translocation, and familial nonsyndromic clear cell RCC. We also include a synopsis of renal medullary carcinoma because of its association with hereditary hemoglobinopathies.

Educational paper: screening in cancer predisposition syndromes: guidelines for the general pediatrician

Improvements in our understanding of the genetic basis of human disease and increased utilization of genetic testing have identified a variety of heritable disorders associated with the onset of benign or malignant neoplasms during childhood. In many cases, the optimal management of affected children is dependent upon the early detection and treatment of tumors. Surveillance strategies based on the natural history of these lesions are often complex, requiring clinical examinations and radiologic and laboratory studies that evolve over a patient's lifetime. A general pediatrician may be the first to suspect one of these disorders in a patient, or may be faced with questions regarding genetic testing, cancer risk, and cancer screening. The pediatrician may also coordinate and interpret the results of specific surveillance studies. In this review, we present the genetic etiology, presentation, natural history, and surveillance recommendations for four disparate hereditary tumor predisposing syndromes, including Beckwith-Wiedemann syndrome/idiopathic hemihyperplasia, von Hippel-Lindau disease, Li-Fraumeni syndrome, and rhabdoid tumor/schwannomatosis. These examples are meant to offer the clinician practical recommendations as well as a framework upon which to base the understanding and management of other conditions associated with an increased risk to develop tumors in childhood.

Neurosurgical considerations in von Hippel-Lindau disease

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

Pheochromocytoma in a 2.75-year-old-girl with a germline von Hippel-Lindau mutation Q164R

Pheochromocytomas are rare tumors of the adrenal gland occurring sporadically or as part of familial cancer syndromes. Here we report on the case of a pheochromocytoma due to the germline missense mutation c.491A>G (Q164R) in exon 3 of the von Hippel-Lindau gene in a girl as young as 2.75 years. Extended analyses of her relatives showed that the mutation occurred de novo in the patient's father who was subsequently diagnosed with bilateral pheochromocytomas and a retinal angioma. To the best of our knowledge, this is the youngest patient presenting with pheochromocytoma so far described in the literature. The same VHL mutation has been reported in a patient who developed a pheochromocytoma at the age of 10 years; therefore, for known VHL Q164R mutation carriers, we suggest screening for pheochromocytoma beginning at 2 years of age.

S100P, von Hippel-Lindau gene product, and IMP3 serve as a useful immunohistochemical panel in the diagnosis of adenocarcinoma on endoscopic bile duct biopsy

Histopathologic distinction between benign and malignant bile duct epithelial lesions on endoscopic biopsies can be extremely challenging because of limited material, crush artifact, and compounding inflammatory and/or reactive changes particularly after stent placement. In this study, a total of 72 endoscopic bile duct biopsies, including 40 adenocarcinomas and 32 benign cases, were immunohistochemically examined for the expression of S100P, von Hippel-Lindau gene product (pVHL), and IMP3 to evaluate their diagnostic value. The results showed that 36 adenocarcinomas (90%) exhibited strong nuclear and cytoplasmic staining for S100P, of which 30 (83.3%) showed diffuse immunoreactivity. Intermediate to strong cytoplasmic staining for IMP3 was demonstrated in 31 tumors (77.5%) (15 diffuse, 16 focal). Completely negative staining for pVHL was observed in 37 adenocarcinomas. In the remaining 3 tumors, focal (1) or diffuse (2) membranous and cytoplasmic pVHL immunoreactivity was detected. Twenty-eight tumors (70%) showed a S100P+/IMP3+/pVHL- staining pattern, 6 (15%) with a S100P+/IMP3-/pVHL- pattern, and 2 (5%) with a S100P-/IMP3+/pVHL- pattern. All 32 benign biopsies were completely negative for IMP3 with the exception of 2 cases with focal dysplasia where focal immunoreactivity was observed. Thirty benign biopsies (93.8%) were positive for pVHL with a diffuse staining pattern observed in 28 cases (93.3%). Eight benign biopsies (25%) showed focal S100P positivity. Twenty-two benign biopsies (68.8%) displayed a S100P-/IMP3-/pVHL+ staining pattern. In conclusion, an immunohistochemical panel consisting of S100P, pVHL, and IMP3 can be helpful in distinguishing adenocarcinoma from reactive epithelial changes on challenging bile duct biopsies. The findings of focal S100P and/or IMP3 expression with reciprocal loss of pVHL immunoreactivity in a few benign biopsies suggest a use of these markers in the detection of early epithelial dysplasia that may be beyond histologic recognition.

Integrative genomics reveals mechanisms of copy number alterations responsible for transcriptional deregulation in colorectal cancer

To evaluate the mechanisms and consequences of chromosomal aberrations in colorectal cancer (CRC), we used a combination of spectral karyotyping, array comparative genomic hybridization (aCGH), and array-based global gene expression profiling on 31 primary carcinomas and 15 established cell lines. Importantly, aCGH showed that the genomic profiles of primary tumors are recapitulated in the cell lines. We revealed a preponderance of chromosome breakpoints at sites of copy number variants (CNVs) in the CRC cell lines, a novel mechanism of DNA breakage in cancer. The integration of gene expression and aCGH led to the identification of 157 genes localized within high-level copy number changes whose transcriptional deregulation was significantly affected across all of the samples, thereby suggesting that these genes play a functional role in CRC. Genomic amplification at 8q24 was the most recurrent event and led to the overexpression of MYC and FAM84B. Copy number dependent gene expression resulted in deregulation of known cancer genes such as APC, FGFR2, and ERBB2. The identification of only 36 genes whose localization near a breakpoint could account for their observed deregulated expression demonstrates that the major mechanism for transcriptional deregulation in CRC is genomic copy number changes resulting from chromosomal aberrations.

Plasma proteome profiling of von Hippel-Lindau disease after total and subtotal nephrectomy: a preliminary study

OBJECTIVES

Common treatment of renal cell carcinoma associated with von Hippel-Lindau (VHL) disease is total (bilateral) or subtotal nephrectomy. Whereas total nephrectomy is associated with absolutely no residual renal function, subtotal nephrectomy frequently leads to chronic kidney disease (CKD) with some residual renal functions. However, molecular mechanisms underlying CKD remain unclear and the diagnosis of CKD is frequently accomplished at its late stage.

DESIGN AND METHODS

We performed a plasma proteomics study to compare the plasma proteome profile of VHL patient who underwent total nephrectomy to the profiles of VHL patient with subtotal nephrectomy and healthy control. Totally 100 mug proteins from each sample was resolved by two-dimensional electrophoresis (2-DE) in triplicate and visualized with SYPRO Ruby fluorescence stain.

RESULTS

The normal plasma proteome profile markedly differed from the profiles of VHL patients. Comparative analysis between total versus subtotal nephrectomized patients revealed significant differences in levels of 20 plasma proteins. Pathway analysis revealed two important networks involving in lipid metabolism, molecular transport, carbohydrate metabolism, cellular growth and proliferation, and small molecule biochemistry, in which these identified and other proteins interplayed.

CONCLUSIONS

Our data identified potential biomarkers for CKD. Further characterization of these identified proteins might also lead to better understanding of molecular mechanisms underlying CKD.

Patterns of gene expression and copy-number alterations in von-hippel lindau disease-associated and sporadic clear cell carcinoma of the kidney

Recent insights into the role of the von-Hippel Lindau (VHL) tumor suppressor gene in hereditary and sporadic clear-cell renal cell carcinoma (ccRCC) have led to new treatments for patients with metastatic ccRCC, although virtually all patients eventually succumb to the disease. We performed an integrated, genome-wide analysis of copy-number changes and gene expression profiles in 90 tumors, including both sporadic and VHL disease-associated tumors, in hopes of identifying new therapeutic targets in ccRCC. We identified 14 regions of nonrandom copy-number change, including 7 regions of amplification (1q, 2q, 5q, 7q, 8q, 12p, and 20q) and 7 regions of deletion (1p, 3p, 4q, 6q, 8p, 9p, and 14q). An analysis aimed at identifying the relevant genes revealed VHL as one of three genes in the 3p deletion peak, CDKN2A and CDKN2B as the only genes in the 9p deletion peak, and MYC as the only gene in the 8q amplification peak. An integrated analysis to identify genes in amplification peaks that are consistently overexpressed among amplified samples confirmed MYC as a potential target of 8q amplification and identified candidate oncogenes in the other regions. A comparison of genomic profiles revealed that VHL disease-associated tumors are similar to a subgroup of sporadic tumors and thus more homogeneous overall. Sporadic tumors without evidence of biallelic VHL inactivation fell into two groups: one group with genomic profiles highly dissimilar to the majority of ccRCC and a second group with genomic profiles that are much more similar to tumors with biallelic inactivation of VHL.