Activity of the hypoxia inducible HIF-alpha transcription factors drive the hypoxic response, resulting in enhancement of angiogenesis, tumour growth, invasion and metastasis. Seeking to uncover a role for Tid1 in control of HIF2-alpha, we used lentiviral shRNA to knock-down Tid1 in 786-0 RCC cells with and without pVHL. In 786-0 cells stably expressing pVHL30, Tid1 knock-down resulted in a dramatic reduction in HIF2-alpha levels relative to controls. Adenoviral-mediated overexpression of Tid1S rescued this decline in HIF2-alpha levels, while overexpression of Tid1L enhanced this decline. A protective role of Tid1S for HIF2-alpha was reproduced in a HEK293 cell model. Immunoprecipitations in HEK293 cells revealed a lack of direct binding between HIF2-alpha and Tid1 in vivo, while adenoviral-mediated overexpression of Tid1 in this model failed to alter in vitro binding between HIF2-alpha and pVHL30. We present a model in which Tid1 regulates HIF2-alpha stability through regulation of pVHL30 nuclear import.

SCIENTIFIC REPORTS へのhyperlink http://www.nature.com/articles/srep19118 / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19926号 / 医博第4146号 / 新制||医||1017(附属図書館) / 33012 / 京都大学大学院医学研究科医学専攻 / (主査)教授 岩井 一宏, 教授 井上 治久, 教授 影山 龍一郎 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

La diffusion dans le sang des cellules tumorales circulantes (CTC) à partir de la tumeur primitive est un signe précoce d’invasivité tumorale et du risque de développer des métastases. Par conséquent, la capacité à les détecter de façon très sensible et spécifique est censée constituer un test cliniquement important pour le pronostic du cancer, le suivi des patients et la personnalisation de la thérapie. Les CTC sont des cellules rares, et plusieurs méthodes ont été proposées pour leur détection. La technique ISET (Isolation by Size of Epithelial/Tumor cells) se base sur la différence de taille des CTC par rapport aux cellules leucocytaires et a montré une très grande sensibilité d’isolement et spécificité d’identification des CTC. Elle permet l’analyse cytopathologique, immunologique et moléculaire des cellules isolées.Le cancer du rein représente 3% des cancers de l’adulte, dans 75% des cas il s’agit d’un carcinome rénal à cellules claires (RCC). Sur le plan génétique, il est un des rarissimes cancers solides caractérisé par des variations de l’ADN, il s’agit de mutations au niveau du gène VHL.Ce projet de recherche vise l’analyse comparative, moléculaire et cytopathologique, des CTC isolées à partir des patients avec RCC dans le but d’évaluer, par une approche moléculaire, les critères cytopathologiques diagnostiques des CTC. Notre étude a porté sur 29 patients ayant bénéficié de l’isolement des CTC par ISET avant toute intervention chirurgicale.L’analyse cytopathologique a été réalisée utilisant les critères décrits par l’équipe de P. Hofman pour définir les CTC (CNHC-MF) et les Cellules Atypiques Circulantes « CAC » (CNHC-UMF). L’analyse génétique par séquençage du gène VHL a été réalisée avec succès sur l’ADN de 205 cellules individuelles, sur l’ADN issu du tissu tumoral et sur l’ADN génomique de chaque patient.Sur les 29 tumeurs étudiées, 25 étaient caractérisées par des mutations du gène VHL. Cent soixante et une cellules, CTC et CAC, isolées à partir du sang de ces 25 patients, ont présenté des variations génétiques du gène VHL identiques à l’ADN issu du tissu tumoral. Il s’agit de 18 mutations différentes affectant les 3 exons de ce gène. Nous avons trouvé des CTC/CAC dans 29/30 des patients avec CCRC analysés. Des mutations VHL ont été trouvées dans 25 des 29 tumeurs CCRC correspondantes. Nous avons obtenu des résultats spécifiques VHL dans 205 des 327 CTC/CAC microdisséquées, comprenant 64 CTC et 141 CAC, selon l’analyse cytopathologique. Les mutations VHL ont été détectées en aveugle dans 57/64 CTC et dans 125/141 CAC. Cependant, nous avons observé que les 8 et 16 CTC et CAC restantes, respectivement, avaient été isolées de patients sans mutations VHL détectables dans le tissu tumoral.Conclusion : Ceci est la première étude comparative de diagnostic génétique et cytopathologique des CTC/CAC chez des patients avec un cancer solide, le CRCC. Nos résultats suggèrent que des critères cytopathologiques élargis pourraient être appliqués au diagnostic des CTC chez les patients avec CCRC. Bien que des études complémentaires et plus élargies soient maintenant nécessaires, cette méthode ouvre la voie à une approche génétique pour le diagnostic des Cellules Tumorales Circulantes / Dissemination in the circulating tumor cells (CTC) from the primary tumor is an early sign of tumor invasion and risk of metastases. Therefore, the ability to detect CTC through a very sensitive and specific test is expected to be clinically important for cancer prognosis, patient monitoring and customization of therapy. CTCs are rare cells, and several methods have been proposed for their detection. The ISET technique (Isolation by Size of Epithelial /Tumor cells) is based on the difference in size of CTC as compared to leucocytes and provides high sensitivity of CTC isolation and high specificity of CTC identification. This methods also allows cytopathological, immunological and molecular analyses of the isolated cellsKidney cancer accounts for 3% of adult cancers and is a clear cell renal cell carcinoma (RCC) in 75% of cases. RCC is one of very rare cancers characterized by a DNA mutations. IRCC tumor cells are in fact characterized by by mutations in the VHL gene. This research project aims at a comparative molecular and cytopathological analysis of, CTCs isolated from patients with RCC in order to evaluate, through a molecular approach, the diagnostic criteria used for cytopathological identification of CTC. Our study included 29 patients tested by the ISET technique before surgery.The cytopathological analysis was performed using the criteria described by the group of P. Hofman to define CTC (CNHC-MF) and Circulating Atypical Cells "CAC" (UMF-CNHC). Genetic analysis of the VHL gene was successfully performed by sequencing on DNA from 205 individual cells isolated by ISET, on DNA from tumor tissue and on genomic DNA from each patient. Of the 29 tumors studied, 25 were characterized by mutations in the VHL gene. One hundred and sixty-one cells, CTC and CAC, isolated from the blood of the 25 patients, with the tumor having VHL mutation, showed genetic variations in the VHL gene identical to those found in the DNA from the tumor tissue. We found 18 different mutations affecting the three exons of this gene.We found CTC/CAC in 29/30 analyzed patients with CCRC. VHL mutations were found in the tumor of 25 out of the corresponding 29 CCRC tumors. Among 327 microdissected CTC/CAC, we obtained VHL-specific results in 205 including 64 CTC and 141 CAC, according to the cytopathological analysis. VHL mutations were blindly detected in 57/64 CTC and in 125/141 CAC. However, we then observed that the 8 and 16 residual CTC and CAC, respectively, had been isolated from patients without detectable VHL mutations in the tumor tissue. Conclusion: This is the first study comparing genetic and cytopathological diagnosis of CTC/CAC in patients with a solid cancer, CRCC. Our results suggest that broaden cytopathological criteria could be applied to the diagnosis of CTC in patients with CCRC. Although further and larger studies are now needed, this approach opens the way to a genetic approach for the accurate diagnosis of Circulating Tumor Cells.

A presente tese investiga o potencial de inserção das Redes de Informação Científica nos processos de ensino-aprendizagem em Ambiente Virtual de Aprendizagem (AVA) como apoio para o ensino exclusivamente a distância quanto como apoio ao ensino presencial. Como suporte a investigação, procurou-se construir panorama teórico fundamentado em estudos sobre a contribuição das TICs para o desenvolvimento e aperfeiçoamento de propostas e projetos, os desafios para usos das TICs na integração dos ambientes presenciais e virtuais de aprendizagem, no ensino em redes colaborativas de informação e no favorecimento à aprendizagem cooperativa, centrada no indivíduo e autônoma. Trata-se de uma pesquisa exploratória de caráter descritivo e aplicado. O campo de pesquisa é a Rede BVS Odontologia Brasil, composta por 17 instituições de ensino, pesquisa e extensão. Para investigar a infraestrutura e capacitação dos profissionais bibliotecários para inserção neste novo ambiente foram entrevistados diretores das bibliotecas integrantes da Rede utilizando a ferramenta Adobe Connect no período de dezembro/2014 a março/2015. A pesquisa revelou que, apesar do grande potencial para apoio à atividades de Ensino-Aprendizagem virtual no âmbito da área de conhecimento, a inserção da Rede BVS Odontologia nos ambientes virtuais de aprendizagem ainda se mostra pouco efetiva. Verificou-se que falta uma cultura de inovação, bem como um planejamento estratégico, tanto por parte das instituições como das bibliotecas, para a formulação e implementação de política de inovação relacionada a cinco aspectos fundamentais: a) a concepção de redes como um processo de ensino-aprendizagem pautado na construção e não na reprodução do conhecimento, aliada a um entendimento do potencial comunicacional dos ambientes virtuais de aprendizagem; b) o aproveitamento do potencial de inserção das redes de informação científica e a apropriação de seus aspectos fundamentais, tendo os ambientes virtuais como espaços de colaboração e autoria; c) uma visão do profissional bibliotecário que leve à construção de propostas formativas, atentando para a contribuição da perspectiva da experiência on-line como mais um canal de produção e disseminação da informação; d) a integração dos sujeitos que atuam em ambientes virtuais de aprendizagem; e) definição de políticas institucionais para ensino-aprendizagem em ambientes virtuais que sejam concebidas de forma colaborativa, considerando a necessidade de infra-estrutura e pessoal capacitado para atuação nesses novos ambientes. / The present thesis investigates the potential for insertion of Scientific Information Networks in the teaching-learning processes in the Learning Management System (LMS) as support for teaching exclusively by distance as to support for presential teaching. As support for investigation, we tried to build theoretical scenario based on studies on the contribution of ICT, for the development and improvement of proposals and projects, challenges to ICT use, in the integration of presential and virtual learning environments, in teaching in collaborative networks of information and in fostering cooperative learning, centered on the individual and autonomous. This is an exploratory research of descriptive and applied character. The research field is the VHL Network Dentistry Brazil, made up of 17 educational, research and extension institutions. To investigate the infrastructure and capacity of librarians for insertion in this new environment they were interviewed directors of Network members libraries using the Adobe Connect tool from December / 2014 to March / 2015. The research has revealed that despite the great potential for support of virtual Teaching-Learning activities in the framework of area of knowledge, the insertion of the VHL Dentistry Network in virtual learning environments also shown less effective. It was found that lack a culture of innovation as well as a strategic plan, both by institutions such as libraries, to the formulation and implementation of innovation policy related to five fundamental aspects: a) network conception as a process of teaching-learning process lined in construction and not in the reproduction of knowledge allied to an understanding of the communication potential of virtual learning environments; b) the harnessing of potential for insertion of scientific information networks and the appropriation of its fundamental aspects, having virtual environments such as collaboration spaces and authorship; c) a vision of librarian leading to the construction of proposals, to attempt to the contribution from the perspective of on-line experience as an a one more dissemination channel of information; d) the integration of subjects that act in practice on learning virtual environments; e) the definition of institutional policies for teaching-learning in virtual environments that are designed collectively.

Le syndrome von Hippel Lindau (VHL) prédispose au développement de multiples tumeurs hautement vascularisées, telles que des hémangioblastomes rétiniens ou du système nerveux central, des phéochromocytomes et des carcinomes rénaux à cellules claires (CCRCC). Les patients atteints de ce syndrome sont porteurs d’une mutation du gène VHL. Ce gène, composé de trois exons, est transcrit en deux ARN messagers par épissage alternatif de l’exon 2. L’ARNm composé des 3 exons (variant #1) est la forme majoritairement exprimée par rapport à l’ARNm dépourvu de l’exon 2 (variant #2). Toutefois, une diminution du ratio variant #1/variant #2 a été essentiellement décrite dans deux situations : (i) dans les tissus embryonnaires humains et en particulier le rein, et (ii) dans certains CCRCC. Ces données suggèrent un rôle potentiel de ce variant #2 dans la tumorigenèse rénale. Deux protéines, pVHL213 et pVHL160, sont produites à partir du variant #1 et elles agissent comme suppresseurs de tumeur. Au début de ce travail, l’expression de l’isoforme protéique pVHL172 produite à partir du variant #2 restait à démontrer et sa fonction était inconnue. Les travaux effectués au cours de cette thèse ont permis de mettre en évidence l’expression de pVHL172 dans des lignées cellulaires et dans des tissus tumoraux grâce à un nouvel anticorps monoclonal de souris dirigé contre les trois isoformes protéiques humaines de pVHL. Pour savoir si l’isoforme pVHL172 a un rôle de suppresseur de tumeur, des lignées cellulaires tumorales rénales exprimant stablement cette protéine ont été établies puis des expériences de xénogreffes de ces cellules chez la souris ont été réalisées. Non seulement pVHL172 n’inhibe pas la formation de tumeurs mais son expression induit un phénotype tumoral plus agressif avec une composante sarcomatoïde plus importante ainsi qu’une vascularisation immature plus conséquente que dans les tumeurs contrôles (n’exprimant pas pVHL). De plus, pVHL172 augmente l’expression des métalloprotéases de matrice MMP1 et MMP13, en partie via l’activation de la voie de signalisation Smad-dépendante du TGF-β. Par ailleurs, des partenaires protéiques de cette protéine ont été recherchés par une analyse protéomique différentielle. Les réseaux d’interaction réalisés à partir des protéines identifiées concernent entre autres la régulation de la matrice extracellulaire et le contrôle qualité des protéines. En conclusion, ce travail a montré que le gène VHL produit des isoformes protéiques avec des fonctions distinctes voire antagonistes, ce qui implique que la balance de leur expression influencerait la progression tumorale rénale. Chez certains patients, une augmentation de l’expression de pVHL172 pourrait être corrélée à une pathologie plus sévère. Ce travail montre l’intérêt de poursuivre l’étude des fonctions de cette protéine pour une meilleure compréhension de son implication dans le cancer du rein et dans la maladie VHL afin d’envisager de nouvelles approches thérapeutiques. / VHL disease predisposes to the development of multiple and highly vascularized tumors, including central nervous system and retinal haemangioblastomas, phaeochromocytomas and clear cell renal cell carcinomas (ccRCCs). Patients with VHL disease harbor a mutant allele of the VHL gene. This gene is transcribed into two mRNAs by alternative splicing of the exon 2. The mRNA variant #1 composed of 3 exons usually predominates over the mRNA variant #2 lacking exon 2. A decrease of the variant #1/variant #2 ratio was however described in 2 situations: (i) in embryonic tissues, particularly in the kidney, and (ii) in some ccRCCs. These data suggest a potential role for the variant #2 in kidney tumorigenesis. pVHL213 and pVHL160 are the two proteins encoded by the mRNA variant #1 and act as tumor suppressors. At the beginning of this Ph.D. project, the expression of pVHL172 isoform encoded by the mRNA variant #2 remained to be established and its function was unknown. The experiments performed during this Ph.D. shed light on pVHL172 expression in cell lines and in tumor tissues using a newly produced mouse monoclonal antibody recognizing the three human pVHL isoforms. To examine if pVHL172 had a tumor suppressor function, human kidney tumor cell lines stably expressing this isoform were established, characterized and then grafted in mice. pVHL172 not only inhibits tumor formation, but its expression also induces a more aggressive phenotype with a higher sarcomatoid component and a more immature vasculature compared to control tumors (that do not express any pVHL). Moreover, pVHL172 increases the matrix metalloproteases MMP1 and MMP13 expression, partly by the activation of the Smad-dependent TGF-β signalling pathway. Besides, we looked for protein partners of pVHL172 by a differential proteomic analysis and showed that interaction networks obtained with the identified proteins are related to extracellular matrix regulation and protein quality control. To conclude, this work demonstrated that the VHL gene encodes protein isoforms with distinct and even antagonistic functions. The balance of expression of these isoforms is likely to influence kidney tumor progression. For some patients, an increase of pVHL172 expression could be correlated with a more severe pathology. This work shows the importance of further studying this isoform’s functions to better understand its involvement in kidney cancer and in VHL disease, so that new therapeutic approaches could be developed.

A presente tese investiga o potencial de inserção das Redes de Informação Científica nos processos de ensino-aprendizagem em Ambiente Virtual de Aprendizagem (AVA) como apoio para o ensino exclusivamente a distância quanto como apoio ao ensino presencial. Como suporte a investigação, procurou-se construir panorama teórico fundamentado em estudos sobre a contribuição das TICs para o desenvolvimento e aperfeiçoamento de propostas e projetos, os desafios para usos das TICs na integração dos ambientes presenciais e virtuais de aprendizagem, no ensino em redes colaborativas de informação e no favorecimento à aprendizagem cooperativa, centrada no indivíduo e autônoma. Trata-se de uma pesquisa exploratória de caráter descritivo e aplicado. O campo de pesquisa é a Rede BVS Odontologia Brasil, composta por 17 instituições de ensino, pesquisa e extensão. Para investigar a infraestrutura e capacitação dos profissionais bibliotecários para inserção neste novo ambiente foram entrevistados diretores das bibliotecas integrantes da Rede utilizando a ferramenta Adobe Connect no período de dezembro/2014 a março/2015. A pesquisa revelou que, apesar do grande potencial para apoio à atividades de Ensino-Aprendizagem virtual no âmbito da área de conhecimento, a inserção da Rede BVS Odontologia nos ambientes virtuais de aprendizagem ainda se mostra pouco efetiva. Verificou-se que falta uma cultura de inovação, bem como um planejamento estratégico, tanto por parte das instituições como das bibliotecas, para a formulação e implementação de política de inovação relacionada a cinco aspectos fundamentais: a) a concepção de redes como um processo de ensino-aprendizagem pautado na construção e não na reprodução do conhecimento, aliada a um entendimento do potencial comunicacional dos ambientes virtuais de aprendizagem; b) o aproveitamento do potencial de inserção das redes de informação científica e a apropriação de seus aspectos fundamentais, tendo os ambientes virtuais como espaços de colaboração e autoria; c) uma visão do profissional bibliotecário que leve à construção de propostas formativas, atentando para a contribuição da perspectiva da experiência on-line como mais um canal de produção e disseminação da informação; d) a integração dos sujeitos que atuam em ambientes virtuais de aprendizagem; e) definição de políticas institucionais para ensino-aprendizagem em ambientes virtuais que sejam concebidas de forma colaborativa, considerando a necessidade de infra-estrutura e pessoal capacitado para atuação nesses novos ambientes. / The present thesis investigates the potential for insertion of Scientific Information Networks in the teaching-learning processes in the Learning Management System (LMS) as support for teaching exclusively by distance as to support for presential teaching. As support for investigation, we tried to build theoretical scenario based on studies on the contribution of ICT, for the development and improvement of proposals and projects, challenges to ICT use, in the integration of presential and virtual learning environments, in teaching in collaborative networks of information and in fostering cooperative learning, centered on the individual and autonomous. This is an exploratory research of descriptive and applied character. The research field is the VHL Network Dentistry Brazil, made up of 17 educational, research and extension institutions. To investigate the infrastructure and capacity of librarians for insertion in this new environment they were interviewed directors of Network members libraries using the Adobe Connect tool from December / 2014 to March / 2015. The research has revealed that despite the great potential for support of virtual Teaching-Learning activities in the framework of area of knowledge, the insertion of the VHL Dentistry Network in virtual learning environments also shown less effective. It was found that lack a culture of innovation as well as a strategic plan, both by institutions such as libraries, to the formulation and implementation of innovation policy related to five fundamental aspects: a) network conception as a process of teaching-learning process lined in construction and not in the reproduction of knowledge allied to an understanding of the communication potential of virtual learning environments; b) the harnessing of potential for insertion of scientific information networks and the appropriation of its fundamental aspects, having virtual environments such as collaboration spaces and authorship; c) a vision of librarian leading to the construction of proposals, to attempt to the contribution from the perspective of on-line experience as an a one more dissemination channel of information; d) the integration of subjects that act in practice on learning virtual environments; e) the definition of institutional policies for teaching-learning in virtual environments that are designed collectively.

La diffusion dans le sang des cellules tumorales circulantes (CTC) à partir de la tumeur primitive est un signe précoce d'invasivité tumorale et du risque de développer des métastases. Par conséquent, la capacité à les détecter de façon très sensible et spécifique est censée constituer un test cliniquement important pour le pronostic du cancer, le suivi des patients et la personnalisation de la thérapie. Les CTC sont des cellules rares, et plusieurs méthodes ont été proposées pour leur détection. La technique ISET (Isolation by Size of Epithelial/Tumor cells) se base sur la différence de taille des CTC par rapport aux cellules leucocytaires et a montré une très grande sensibilité d'isolement et spécificité d'identification des CTC. Elle permet l'analyse cytopathologique, immunologique et moléculaire des cellules isolées.Le cancer du rein représente 3% des cancers de l'adulte, dans 75% des cas il s'agit d'un carcinome rénal à cellules claires (RCC). Sur le plan génétique, il est un des rarissimes cancers solides caractérisé par des variations de l'ADN, il s'agit de mutations au niveau du gène VHL.Ce projet de recherche vise l'analyse comparative, moléculaire et cytopathologique, des CTC isolées à partir des patients avec RCC dans le but d'évaluer, par une approche moléculaire, les critères cytopathologiques diagnostiques des CTC. Notre étude a porté sur 29 patients ayant bénéficié de l'isolement des CTC par ISET avant toute intervention chirurgicale.L'analyse cytopathologique a été réalisée utilisant les critères décrits par l'équipe de P. Hofman pour définir les CTC (CNHC-MF) et les Cellules Atypiques Circulantes " CAC " (CNHC-UMF). L'analyse génétique par séquençage du gène VHL a été réalisée avec succès sur l'ADN de 205 cellules individuelles, sur l'ADN issu du tissu tumoral et sur l'ADN génomique de chaque patient.Sur les 29 tumeurs étudiées, 25 étaient caractérisées par des mutations du gène VHL. Cent soixante et une cellules, CTC et CAC, isolées à partir du sang de ces 25 patients, ont présenté des variations génétiques du gène VHL identiques à l'ADN issu du tissu tumoral. Il s'agit de 18 mutations différentes affectant les 3 exons de ce gène. Nous avons trouvé des CTC/CAC dans 29/30 des patients avec CCRC analysés. Des mutations VHL ont été trouvées dans 25 des 29 tumeurs CCRC correspondantes. Nous avons obtenu des résultats spécifiques VHL dans 205 des 327 CTC/CAC microdisséquées, comprenant 64 CTC et 141 CAC, selon l'analyse cytopathologique. Les mutations VHL ont été détectées en aveugle dans 57/64 CTC et dans 125/141 CAC. Cependant, nous avons observé que les 8 et 16 CTC et CAC restantes, respectivement, avaient été isolées de patients sans mutations VHL détectables dans le tissu tumoral.Conclusion : Ceci est la première étude comparative de diagnostic génétique et cytopathologique des CTC/CAC chez des patients avec un cancer solide, le CRCC. Nos résultats suggèrent que des critères cytopathologiques élargis pourraient être appliqués au diagnostic des CTC chez les patients avec CCRC. Bien que des études complémentaires et plus élargies soient maintenant nécessaires, cette méthode ouvre la voie à une approche génétique pour le diagnostic des Cellules Tumorales Circulantes

Von Hippel-Lindau (VHL) syndrome is an autosomal dominant predisposition to cancer in neurological tissues, the kidneys, adrenal glands, pancreas, and liver, including neurological hemangioblastoma (HB), pheochromocytoma (PCC), pancreatic neuroendocrine tumors (PNET), pancreatic and renal cysts, and clear cell renal cell carcinoma (ccRCC). The disease process follows Knudson's two-hit model, requiring spontaneous loss or mutation of a normal VHL tumor suppressor allele to induce expression of the disease. VHL syndrome principally involves dysregulation of oxygen sensing pathways including the Hypoxia Inducible Factor (HIF)-Vascular Endothelial Growth Factor-A (VEGF-A) and HIF-Erythropoietin (EPO) pathways. RNA sequencing (RNA-Seq) data from our previously published experiments revealed a potentially novel VEGF-A splice variant with excision of the VEGF Receptor-1 (VEGFR-1)/Flt-1 binding domain, rendering this isoform resistant to native down-regulation. Additionally, phenotypic changes were observed in adult VHL mutant mice, specifically very red appearing extremities with prominently visible vasculature. In order to determine the etiology of this phenotype, we observed red blood cell count, Epo gene expression levels, and arterialization of the blood vessels in these experimental mice as compared to littermate controls. Current research into the VEGF-A isoform is ongoing in the lab, and preliminary evidence for the etiology of the apparent chronic erythema phenotype is inconclusive due to lack of experimental replicates due to COVID-19 quarantine orders. / Master of Science / Von Hippel-Lindau (VHL) syndrome is characterized by cancer development primarily in the brain and spinal cord, kidneys, adrenal glands, pancreas, and liver. VHL syndrome involves mutations which render the VHL gene dysfunctional. Since the VHL gene's normal role is one of preventing cancer development, sensing oxygen levels, and impacting blood vessel development, it follows that the loss of this gene results in tumor development with a rich blood vessel network. One of the downstream effectors of this process is a signaling molecule called Vascular Endothelial Growth Factor-A (VEGF-A). Our lab found a unique variant of VEGF-A, which may be overactive in the body in the setting of VHL disease. Additionally, we noted that our VHL mutant mice turned very red, and we sought to identify the biological cause of this phenomenon. In order to determine the cause of this redness, we studied red blood cell counts and their regulatory gene (Erythropoietin, EPO), as well as potential blood vessel abnormalities using high-power microscopy.