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

Diagnostic imaging of gastrointestinal neuroendocrine neoplasms with a focus on ultrasound

The diagnosis of gastrointestinal neuroendocrine neoplasms represents a significant diagnostic challenge since these tumours have a various, often non-specific clinical presentation. Currently, more than half of gastroenteropancreatic neuroendocrine neoplasms are detected incidentally, usually during surgery, diagnostic imaging studies or endoscopic procedures performed for other indications. Sometimes the first symptom of the disease is the presence of metastatic lesions in the liver. A neuroendocrine tumour is diagnosed based on the clinical presentation, assessment of specific and non-specific biochemical markers, imaging studies and histopathological examination. Focal lesions, both primary and metastatic may be small and often have an atypical location. Diagnostic imaging of neuroendocrine tumours is of fundamental importance for determining the location of the primary lesion, staging of the disease, selection of treatment and monitoring of its effects. In addition, diagnostic imaging make it possible not only to detect tumours, but also to perform therapeutic procedures based on the result. Transabdominal ultrasound is one of the first diagnostic imaging method for neuroendocrine neoplasms. New ultrasound techniques such as ultrasound elastography, contrast-enhanced ultrasound, endoscopic ultrasound, intraductal and intraoperative ultrasound improve the efficacy of ultrasound examination. Endoscopic ultrasound is a fundamental diagnostic tool for the detection of neuroendocrine tumours of the pancreas and the distal part of the colon. Due to the large variety of neuroendocrine tumours and differences in tumour biology, clinical stage and expression of somatostatin receptors, no single imaging method is sufficient; therefore, in order to determine the right diagnosis and select the best treatment, it is recommended that a combined morphological and functional assessment be used.

Whole exome sequencing identified genetic variations in Chinese hemangioblastoma patients

Hemangioblastomas (HBs) are uncommon tumors characterized by the presence of inactivating alterations in the von Hippel-Lindau (VHL) gene in inherited cases and by infrequent somatic mutation in sporadic entities. We performed whole exome sequencing on 11 HB patients to further elucidate the genetics of HBs. A total of 270 somatic variations in 219 genes, of which there were 86 mutations in 67 genes, were found in sporadic HBs, and 184 mutations were found in 154 genes in familial HBs. C: G>T: A and T: A>C: G mutations are relatively common in most HB patients. Genes harboring the most significant mutations include PCDH9, KLHL12, DCAF4L1, and VHL in sporadic HBs, and ZNF814, DLG2, RIMS1, PNN, and MUC7 in familial HBs. The frequency of CNV varied considerably within sporadic HBs but was relatively similar within familial HBs. Five genes, including OTOGL, PLCB4, SCEL, THSD4, and WWOX, have CNVs in the six patients with sporadic HBs, and three genes, including ABCA6, CWC27, and LAMA2, have CNVs in the five patients with familial HBs. We found new genetic mutations and CNVs that might be involved in HBs; these findings highlight the complexity of the tumorigenesis of HBs and pinpoint potential therapeutic targets for the treatment of HBs.

Neuroprotective effects respond to cerebral ischemia without susceptibility to HB-tumorigenesis in VHL heterozygous knockout mice

The von Hippel-Lindau (VHL) tumor suppressor gene plays a prominent role in the development of hemangioblastomas (HBs) within specific regions of the human' central nervous system (CNS). Alterations in VHL gene are rarely observed in the more common features of human VHL-related tumors in animal models, and VHL heterozygous knockout (VHL+/-) mice do not develop HBs. We tested whether VHL heterozygous knockout mice exhibited genetic predisposition to the development of HBs and conferred a selective advantage involving growth of blood vessels to its carrier. No differences were observed between wild-type and VHL+/- mice in development ad reproduction. The heterozygous VHL+/- mice did not develop higher genetic susceptibility to CNS-HBs over their lifetime. Furthermore, this recessive VHL gene heterozygosity is relatively stable. Interestingly, we found these heterozygous VHL+/- mice gained an advantage conferring to angiogenic ability in a particular environment, compared with wild-type mice. The heterozygous VHL+/- mice obviously enhanced hypoxia inducible factor-1 (HIF)-dependent and Twist1 angiogenic mechanism in response to acute cerebral ischemia, resulting in decreased cerebral tissue damage and neuroprotective response through neovascularization. Our findings provide evidence of partial loss function of VHL as a novel precise therapeutic target in acute cerebral ischemia.

Atypical Renal Cysts: A Morphologic, Immunohistochemical, and Molecular Study

There is a lack of standardized nomenclature for renal cysts lined by multiple cell layers or with short papillary projections but without nests of epithelial cells within the stroma. We retrieved 29 cases (15 nephrectomies, 14 partial nephrectomies) from the surgical pathology files of Johns Hopkins Hospital from 1993 to 2014 and performed immunohistochemistry for CK7, alpha-methylacyl-CoA racemase (AMACR), CAIX, and CD10 and fluorescence in situ hybridization for trisomy 7 and 17 and 3p deletion. The mean age at excision was 58 years (range, 29 to 80 y) with 16 men and 13 women. Mean size was 2.9 cm (range, 0.3 to 10 cm). The cysts were grouped by their morphology into (1) clear cell, (2) eosinophilic stratified, and (3) eosinophilic papillary. By immunohistochemistry, 7/9 (78%) of the clear cell cases were diffusely positive for both CK7 and CAIX resembling the pattern seen in clear cell papillary renal cell carcinoma. The majority of eosinophilic stratified (4/6; 67%) and eosinophilic papillary (12/14; 86%) cases were positive for CK7 and had variable staining for AMACR, CD10, or CAIX, suggesting a differentiation more aligned with papillary renal cell carcinoma. The most common molecular alterations detected were trisomy 17 (n=6) and trisomy 7 (n=4). One case showed deletion of chromosome 3p. Clinical follow-up information was available in 23 patients; 20 were alive with no evidence of disease after a median follow-up of 20 months (range, 3 to 120 mo), 1 patient was dead due to metastatic lung cancer, 1 of sepsis, and 1 of unknown reason. Atypical renal cysts present as complex radiologic lesions, as secondary lesions in patients with a renal mass, or in a background of chronic renal disease. These atypical cysts appear heterogenous, and some follow in their morphology and immunoprofile with well-established renal tumors. The presence of 3p deletion and trisomy 7/17 suggests that in some cases they may be precursors of renal cell carcinoma. Longer follow-up with more cases is needed, but on the basis of our data, these lesions should not be diagnosed as carcinoma.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC): a rapid autopsy report of metastatic renal cell carcinoma

Rapid ("warm") autopsies of patients with advanced metastatic cancer provide invaluable insight into the natural history, pathobiology, and morphology of advanced and treatment-resistant tumors. Here, we report a rapid autopsy case of a hereditary leiomyomatosis and renal cell carcinoma (HLRCC) patient with advanced metastatic renal cell carcinoma (RCC)-the first such case described for either a primary renal tumor or HLRCC-related cancer. Mutations in the fumarate hydratase (FH) gene underlie HLRCC, a rare syndrome involving cutaneous and uterine leiomyomata and aggressive kidney tumors. Loss of heterozygosity at the wild-type FH gene locus results in profound cellular metabolic derangement, "pseudohypoxic" upregulation of hypoxia-inducible factor 1α (HIF-1α)-dependent transcription, and aberrant protein succination; these molecular changes drive oncogenesis of kidney tumors in HLRCC patients. The current index patient had a high-grade RCC with classic morphologic features of HLRCC, including large nuclei with prominent eosinophilic nucleoli and perinucleolar clearing. In addition, this patient's RCC demonstrated extensive sarcomatoid and rhabdoid features-morphologies not previously well described in HLRCC-associated kidney tumors. Here, we report the extent of metastatic dissemination and supplement this unique tumor morphology with mitochondrial enzyme histochemistry and extended immunohistochemical analysis. Tumor cells strongly expressed PAX8, vimentin, CD10, and the HIF target GLUT1 and showed increased nuclear p53 accumulation; the expression of other RCC markers was negative. We also detail microscopic tubular epithelial changes in the grossly uninvolved ipsilateral renal parenchyma and demonstrate sporadic, aberrant upregulation of the HIF targets GLUT1 and CAIX in dysplastic peritumoral tubules.

Gastroenteropancreatic neuroendocrine tumors: role of imaging in diagnosis and management

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of neoplasms that arise from cells of the diffuse neuroendocrine system and are characterized by a wide spectrum of clinical manifestations. All NETs are potentially malignant but differ in their biologic characteristics and the probability of metastatic disease. The pathologic classification of these tumors relies on their proliferation and differentiation. In the past decades, several nomenclatures have been proposed to stratify neuroendocrine tumors, but the World Health Organization classification is the one that is most widely accepted and used. The diagnosis of neuroendocrine tumor relies on clinical manifestation, laboratory parameters, imaging features, and tissue biomarkers in a biopsy specimen. With improved understanding of the natural history and lesion biology, management of GEP-NETs has also evolved. Although surgery remains the only potentially curative therapy for patients with primary GEP-NETs, other available treatments include chemotherapy, interferon, somatostatin analogs, and targeted therapies. Recent improvements in both morphologic and functional imaging methods have contributed immensely to patient care. Morphologic imaging with contrast agent-enhanced multidetector computed tomography and magnetic resonance imaging is most widely used for initial evaluation and staging of disease in these patients, whereas functional imaging techniques are useful both for detection and prognostic evaluation and can change treatment planning.

Altered PTEN, ATRX, CHGA, CHGB, and TP53 expression are associated with aggressive VHL-associated pancreatic neuroendocrine tumors

Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome in which 8-17 % of germline mutation carriers develop pancreatic neuroendocrine tumors (PNETs). There is limited data on prognostic markers for PNETs other than Ki-67, which is included in the World Health Organization classification system. Recently, specific genes and pathways have been identified by whole exome sequencing which may be involved in the tumorigenesis of PNETs and may be markers of disease aggressiveness. The objective of this study was to identify molecular markers of aggressive disease in VHL-associated PNETs. The protein expression of eight genes (PTEN, CHGA, CHGB, ATRX, DAXX, CC-3, VEGF, and TP53) was analyzed in PNETs by immunohistochemistry and compared to clinical data, VHL genotype, functional imaging results, and pathologic findings. Subcellular distribution of phosphatase and tensin (PTEN), chromogranin A (CHGA), and alpha thalassemia/mental retardation syndrome X-linked (ATRX) were significantly different by WHO classifications (p ≤ 0.05). There was decreased PTEN nuclear to cytoplasmic ratio (p < 0.01) and decreased CHGA nuclear expression (p = 0.03) in malignant samples as compared to benign. Lower cytoplasmic chromogranin B (CHGB) expression (p = 0.03) was associated with malignant tumors and metastasis. Higher nuclear expression of PTEN was associated with VHL mutations in exon 3 (p = 0.04). Higher PTEN and CHGB expression was associated with higher FDG-PET avidity (p < 0.05). Cytoplasmic expression of CC-3 was associated with higher serum chromogranin A levels (ρ = 0.72, p = 0.02). Lastly, greater cytoplasmic expression of p53 was associated with metastasis. Our findings suggest that altered PTEN, ATRX, CHGA, and CHGB expression are associated with aggressive PNET phenotype in VHL and may serve as useful adjunct prognostic markers to Ki-67 in PNETs.

Surgical resection of endolymphatic sac tumors in von Hippel-Lindau disease: findings, results, and indications

OBJECTIVES/HYPOTHESIS

To define the surgical treatment and outcomes of von Hippel-Lindau (VHL) disease-associated endolymphatic sac tumors (ELSTs), we analyzed consecutive VHL patients who underwent ELST resection.

STUDY DESIGN

Retrospective investigation of consecutive VHL patients who underwent resection of ELSTs at a clinical research center between 1999 and 2010.

METHODS

Analysis of serial clinical examinations, audiograms, imaging studies, and operative findings were analyzed.

RESULTS

Thirty-one consecutive patients with ELSTs (15 males, 16 females) underwent resection of 33 tumors (mean follow-up, 49.9 ± 48.0 months; range, 1.0-116 months). One patient had bilateral ELST resections and one patient underwent reoperation for recurrence. Mean age at surgery was 38.2 ± 10.2 years (range, 12-67 years). Whereas 29 ears (88%) had direct radiographic evidence of an ELST, four ears (12%) did not. Mean tumor size was 1.3 ± 1.1 cm (range, 0.2-5.2 cm). Whereas two patients (two ears, 6%) were asymptomatic, 29 patients (31 ears, 94% of ears) had associated audiovestibular symptoms, including sensorineural hearing loss (28 ears, 84%), tinnitus (24 ears,73%), and vertigo (21 patients, 68%). Postoperatively, hearing was stabilized (27) or improved (three) in 97% of 31 ears. Complete tumor resection was achieved in 30 ears (91% of 33 ears). Complications included cerebrospinal fluid leak in two ears (6%) and transient lower cranial nerve palsy in one ear (3%).

CONCLUSIONS

Surgical resection of ELSTs can be performed with hearing preservation and a reduction in audiovestibular dysfunction. Early surgical resection can prevent or decrease disabling audiovestibular symptoms, enhance the opportunity for complete resection, and preserve hearing.

Spectrum of preneoplastic and neoplastic cystic lesions of the kidney

CONTEXT

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

OBJECTIVE

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

DATA SOURCES

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

CONCLUSIONS

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

Clinical utility of functional imaging with ¹⁸F-FDOPA in Von Hippel-Lindau syndrome

CONTEXT

Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome in which patients are at risk of developing multiple tumors in different organs. 6-L-¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-FDOPA) positron emission tomography (PET) is a relatively new metabolic imaging tracer proposed for the use of localizing sites of neuroendocrine tumors. There are limited data on the clinical utility of using ¹⁸F-FDOPA PET for identifying neuroendocrine tumors in a high-risk population such as VHL.

OBJECTIVE

The aim of this prospective study was to evaluate the clinical utility of ¹⁸F-FDOPA PET in patients with VHL-related tumors.

DESIGN

Radiological findings were prospectively collected from four imaging modalities: computed tomography, magnetic resonance imaging (MRI), ¹⁸F-fluorodeoxyglucose PET, and ¹⁸F-FDOPA PET. ¹⁸F-FDOPA PET findings were compared with those from other imaging modalities, as well as with clinical and laboratory data, and pathology findings if patients underwent an operation.

RESULTS

In 52 patients with VHL, 390 lesions were identified by computed tomography (n = 139), MRI (n = 117), ¹⁸F-fluorodeoxyglucose PET (n = 94), and ¹⁸F-FDOPA PET (n = 40). ¹⁸F-FDOPA PET identified 20 pancreatic and 20 extrapancreatic tumors, including lesions in the adrenal gland (n = 11), kidney (n = 3), liver (n = 4), lung (n = 1), and cervical paraganglioma (n = 1). These tumor sites were not seen by conventional imaging studies in 9.6% of patients and 4.4% of lesions. Seven of eight patients who had an ¹⁸F-FDOPA PET-positive lesion underwent resection, and pathology showed a neuroendocrine tumor. Four of 10 patients with positive adrenal uptake had elevated catecholamine levels, and six of 10 patients had a discrete mass on axial imaging.

CONCLUSIONS

¹⁸F-FDOPA PET is a useful complementary imaging study to detect neuroendocrine tumors in patients with VHL undergoing surveillance, especially in those suspected to have adrenal pheochromocytoma or unusual ectopic locations.

The Gruppo Otologico experience of endolymphatic sac tumor

OBJECTIVE

Endolymphatic sac tumor (ELST) is a rare low grade adenocarcinoma of the skull base. During the past decade the number of the reported cases has increased. This study exposes our experience in the management of ELST with a review of the literature.

STUDY DESIGN

Retrospective study of patients with ELST at a quaternary referral otology and skull base center.

METHODS

A review of the records from the Gruppo Otologico revealed 7 patients treated for ELST. All papers containing series of three or more cases of ELST published in the English literature were selected for analysis.

RESULTS

Hearing loss and tinnitus were present in almost all our cases. All of them were evaluated with audiometric tests, computed tomography and magnetic resonance imaging. All the patients were treated surgically with preservation of the facial nerve and preoperative embolization was performed in 5 patients. Genetic study was performed on all our cases and revealed the presence of von Hippel-Lindau syndrome in one patient who had the tumor as the initial manifestation of his syndrome. None of the patients received postoperative radiotherapy and one of them had recurrence of the tumor 13 years following surgery.

CONCLUSIONS

Complete surgical resection with preoperative embolization of large tumors is the mainstay treatment for ELST. The facial nerve should not be sacrificed unless it is totally invaded by the tumor. A long term follow up is recommended and the role of postoperative adjunctive radiotherapy is still controversial.

Imaging of cancer predisposition syndromes in children

The term cancer predisposition syndrome (CPS) encompasses a multitude of familial cancers in which a clear mode of inheritance can be established, although a specific gene defect has not been described in all cases. Advances in genetics and the development of new imaging techniques have led to better understanding and early detection of these syndromes and offer the potential for preclinical diagnosis of any associated tumors. As a result, imaging has become an essential component of the clinical approach to management of CPSs and the care of children suspected of having a CPS or with a confirmed diagnosis. Common CPSs in children include neurofibromatosis type 1, Beckwith-Wiedemann syndrome, multiple endocrine neoplasia, Li-Fraumeni syndrome, von Hippel-Lindau syndrome, and familial adenomatous polyposis. Radiologists should be familiar with these syndromes, their common associated tumors, the new imaging techniques that are available, and current screening and surveillance recommendations to optimize the assessment of affected children.

Pediatric endocrine screening for von Hippel-Lindau disease: benefits and the challenge of compliance

Fifteen children and adolescents (4 male) with a median age of 5.4 yr (range 1.2 -13.6 yr) were entered into a screening protocol to identify lesions of von Hippel-Lindau (VHL) disease. Fourteen had an affected first-degree relative and one had a previous VHL lesion. Screening during the period of 2000 to 2008 followed published guidelines and consisted of measurement of urinary catecholamines, adrenal and renal imaging and ophthalmological and central nervous system examinations and imaging. Screening identified 8 VHL lesions in 6 asymptomatic patients with confirmed genetic mutations. Five patients had elevated urinary noradrenaline excretion and in each case the presence of a pheochromocytoma was identified on adrenal magnetic resonance imagin scan. In one patient a left-sided tumor was identified 1 yr after a right-sided tumor had been removed. In a sixth patient a retinal capillary hemangioma and a cerebellar hemangioblastoma were identified. Patient compliance with the screening protocol was variable reflecting its time-intensive nature. A formal screening programme for this at-risk population of pediatric patients, despite being intensive, can identify VHL lesions during a pre-morbid phase and may thus have a beneficial impact on prognosis in this serious disorder.

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

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

Inherited cancer syndromes in children and young adults

Geneticists estimate that 5% to 10% of all cancers diagnosed in the pediatric age range occur in children born with a genetic mutation that directly increases their lifetime risk for neoplasia. However, despite the fact that only a fraction of cancers in children occur as a result of an identified inherited predisposition, characterizing genetic mutations responsible for increased cancer risk in such syndromes has resulted in a profound understanding of relevant molecular pathways involved in carcinogenesis and/or resistance to neoplasia. Importantly, because most cancer predisposition syndromes result in an increased risk of a small number of defined malignancies, personalized prophylactic surveillance and preventive measures can be implemented in affected patients. Lastly, many of the same genetic targets identified from cancer-prone families are mechanistically involved in the majority of sporadic cancers in adults and children, thereby underscoring the clinical relevance of knowledge gained from these defined syndromes and introducing novel therapeutic opportunities to the broader oncologic community. This review highlights the clinical and genetic features of many of the known constitutional genetic syndromes that predispose to malignancy in children and young adults.

VHL frameshift mutation as target of nonsense-mediated mRNA decay in Drosophila melanogaster and human HEK293 cell line

There are many well-studied examples of human phenotypes resulting from nonsense or frameshift mutations that are modulated by Nonsense-Mediated mRNA Decay (NMD), a process that typically degrades transcripts containing premature termination codons (PTCs) in order to prevent translation of unnecessary or aberrant transcripts. Different types of germline mutations in the VHL gene cause the von Hippel-Lindau disease, a dominantly inherited familial cancer syndrome with a marked phenotypic variability and age-dependent penetrance. By generating the Drosophila UAS:Upf1^D45B line we showed the possible involvement of NMD mechanism in the modulation of the c.172delG frameshift mutation located in the exon 1 of Vhl gene. Further, by Quantitative Real-time PCR (QPCR) we demonstrated that the corresponding c.163delG human mutation is targeted by NMD in human HEK 293 cells. The UAS:Upf1^D45B line represents a useful system to identify novel substrates of NMD pathway in Drosophila melanogaster. Finally, we suggest the possible role of NMD on the regulation of VHL mutations.

Renal cystic diseases and renal neoplasms: a mini-review

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

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.

A vitronectin M381T polymorphism increases risk of hemangioblastoma in patients with VHL gene defect

Hemangioblastomas, highly vascular tumors, occur sporadically or associated with von Hippel-Lindau (VHL) disease. Diverse mutations in the VHL gene inactivate the VHL protein and constitute the molecular etiology of the disease. Changes in VHL gene were analyzed in patients with multiplex ligation-dependent probe amplification and single-strand conformation polymorphism analyses. We report here that other angiogenesis-related changes in vitronectin were identified with 2D electrophoresis of plasma samples and restriction fragment length polymorphisms. Our findings revealed that most patients (80.0%) with a familial VHL deletion carried the threonine (T) allele at vitronectin codon 381. Adults simultaneously carrying a VHL defect and the T allele were 5.0-fold more likely to be affected by VHL disease than were methionine/methionine (M/M) homozygotes carrying a VHL defect. Patients with sporadic hemangioblastoma, C-terminally truncated VHL protein or a large deletion in the VHL gene, and the T allele were 18.0-fold more likely to develop recurrent disease. Taken together, individuals with mutated VHL are more likely to be affected by familial or recurrent sporadic hemangioblastoma when carrying the M/T or T/T genotype at codon 381 of vitronectin.