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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Evaluation von Anti-HER-2-Substanzen für die Therapie des kolorektalen Karzinoms / Evaluation of targeting HER-2 as a therapeutic strategy in colorectal cancer

Metzger, Anna-Lena Clara 03 November 2020 (has links)
No description available.
22

Die Bedeutung des Serumantigens des Onkoproteins HER-2/neu für die Diagnostik und Therapie des Mammakarzinoms

Lüftner, Diana 12 February 2004 (has links)
Diese Arbeit beschäftigt sich mit der prognostischen und prädiktiven Bedeutung der Serummessung des shed antigens des Onkoproteins HER-2/neu (s-HER-2/neu) für Mammakarzinompatientinnen in unterschiedlichen Erkrankungsstadien sowie unter verschiedenen Formen der Systemtherapie inklusive der Behandlung mit dem monoklonalen Antikörper Herceptin. Hierbei wurde der Stellenwert von s-HER-2/neu mit weiteren biochemischen Serummarkern (s-EGFR, s-uPA, CA 27.29) und etablierten Prognosefaktoren des Mammakarzinoms verglichen. Da HER-2/neu zu verschiedenen Zeitpunkten der Erkrankung mit verschiedenen Methoden an unterschiedlichen Materialien bestimmt werden kann, mußte schwerpunktmäßig auch die differentielle Wertigkeit von s-HER-2/neu im Vergleich zu Methoden der HER-2/neu-Bestimmung am Tumormaterial untersucht werden. Hierbei wurde insbesondere hinterfragt, ob die verschiedenen Methoden der HER-2/neu-Diagnostik stets zum gleichen Ergebnis führen, welche biologischen und technischen Ursachen möglichen Diskordanzen zugrunde liegen, und welche Konsequenzen diese Diskordanzen für die Therapiewahl (vor allem mit Herceptin beim metastasierten Mammakarzinom) mit sich bringen. Es wurden folgende Ergebnisse erzielt: - Grenzwerte: s-HER-2/neu: 50 ng/ml mit großer Wahrscheinlichkeit auch eine HER-2/neu-Überexpression am Tumorgewebe aufweisen. - Insgesamt 70% der Patientinnen mit HER-2/neu-negativen Tumoren hatten bei der späteren Fernmetastasierung einen erhöhten s-HER-2/neu-Spiegel. Diese Zunahme des Nachweises der HER-2/neu-Positivität zwischen Gewebenachweis am Primärtumor und dem Serumnachweis im Stadium IV ist nicht zufällig (p=0,001) und allenfalls teilweise durch den Einfluß der Tumormasse erklärbar. Klonale Veränderungen müssen in Erwägung gezogen werden. / This work focuses on the prognostic and predictive impact of the determination of the shed antigen of the oncoprotein HER-2/neu in serum (s-HER-2/neu) for breast cancer patients in different stages of the disease as well as under different forms of systemic therapy including treatment with the monocloncal antibody Herceptin. The biological meaning of s-HER-2/neu was compared to other serum markers (s-EGFR, s-uPA, CA 27.29) and established prognostic markers in breast cancer. As HER-2/neu can be measured at different times during the course of the disease using different methods and material, the differential meaning of s-HER-2/neu had to be investigated in relation to methods of HER-2/neu determination in tissue. Key questions were whether different methods of HER-2/neu testing lead to the same result, what biological and/or technical reason may lead to discordances, and if so, which are the consequences of these discordances for therapeutic decision making (before all Herceptin therapy in metastatic breast cancer). The results of the investigations are as follows: - Cut-offs of normal: s-HER-2/neu: 50 ng/ml are most probably HER-2/neu-positive in tissue. - Altogether, 70% of the patients with HER-2/neu negative tumors showed elevated s-HER-2/neu concentrations at later metastatic spread. This increase of the number of HER-2/neu positivity between tissue determination at the primary tumor and the serum results at stage IV disease cannot be explained by pure coincidence (p=0.001) and can only in part be explained by the influence of tumor burden . Clonal changes during the course of the disease must be considered.
23

Avaliação do perfil de expressão gênica de linhagens celulares do tecido mamário com diferentes níveis de expressão do receptor HER-2 tratadas com ácido docosahexaenoico / Evaluation of the gene expression profile of breast tissue cell lines with different expression levels of the HER-2 receptor treated with docosahexaenoic acid

Almeida, Danielle Fontes de 03 May 2013 (has links)
O câncer de mama permanece como segundo tipo de câncer mais frequente no mundo e o primeiro entre as mulheres. Tumores de mama podem ser categorizados pela expressão de receptores como o HER-2 (receptor de fator de crescimento epidermal 2). A hiperexpressão do receptor HER-2 é observada em cerca de 30% dos carcinomas de mama, e está associada a prognósticos desfavoráveis. Os ácidos graxos poli-insaturados (AGPI) , como os ácidos graxos ômega-3, parecem diminuir o risco de câncer de mama. O ácido docosahexaenoico (DHA), um tipo de AGPI ômega-3 parece ter o maior potencial antitumoral no câncer de mama. Alguns mecanismos de ação foram propostos para a ação do DHA no controle do câncer de mama, no entanto, faltam dados para elucidar os mecanismos moleculares do DHA no tecido mamário normal e cancerígeno. Dessa maneira, o objetivo desse trabalho foi avaliar a ação do DHA na modulação da expressão de genes em linhagem celular normal (HB4a), transformada (HB4aC5.2) e de carcinoma mamário humano (SKBR-3). As linhagens estudadas foram tratadas com 100 ?M de DHA ou controle (etanol) durante 72 horas. Após a extração de RNA realizamos a técnica de expressão gênica global (Microarray) para encontrar os genes diferencialmente expressos, em relação ao tratamento com DHA, em cada linhagem celular estudada. Na linhagem normal (HB4a) observamos 174 genes diferencialmente expressos (p<0,01), sendo 136 hiperexpressos e 38 hipoexpressos, na linhagem celular transformada (HB4aC5.2) encontramos 208 genes diferencialmente expressos (p<0,01), sendo 32 hiperexpressos e 176 hipoexpressos. A linhagem do carcinoma mamário (SKBR-3) apresentou 126 genes diferencialmente expressos (p<0,01), sendo 48 hiperexpressos e 78 hipoexpressos. A análise ontológica destes genes permitiu identificar processos biológicos como: adesão celular, diferenciação celular e metabolismo lipídico. Concluímos que o DHA altera o perfil de expressão gênica de maneiras distintas em linhagem normal, transformada e de carcinoma mamário humano. Além disso, encontramos após o tratamento com DHA genes envolvidos com o metabolismo lipídico nas linhagens que hiperexpressam o receptor HER-2 / Breast cancer remains the second most common cancer in the world and first among women. Breast tumors can be categorized by the expression of receptors such as HER-2. Overexpression of HER-2 receptor is associated with unfavorable prognosis.The polyunsaturated fatty acids (PUFAs) omega- 3 appears to decrease the risk of breast cancer. Docosahexaenoic acid (DHA), a type of omega-3 PUFAs, seems to have greater antitumor potential in breast cancer. However, the gene expression profile resulting from the action of DHA in breast cancer has not been elucidated yet. We aimed to examine the effects of DHA on normal breast cell line (HB4a), transformed cell line (HB4aC5.2) and breast cancer cell line (SKBR-3) and using a microarray approach. Cells were treated with 100?M of DHA for 72 hours. We identified 174, 208 and 126 differentially expressed genes after DHA treatment, in HB4a, HB4aC5.2 and SKBR3, respectively. Notably, the molecular pathways for the differentially expressed genes included those related to lipid metabolism, cell growth, molecular transport and cell-to-cell signaling. Where found genes related to overexpression of HER-2 after treatment with DHA. These genes involved in lipid metabolism and were down-expressed after treatment, suggesting a possible mechanism DHA in breast cancer by lipid metabolism control
24

A expressão imuno-histoquímica do marcador molecular Citoqueratina 19 e da proteína Her-2/neu (C-erbB2) em bócios operados na Fundação Hospital Adriano Jorge, em Manaus

Cattebeke, Lesemky Carlile Herculano 12 December 2012 (has links)
Made available in DSpace on 2015-04-20T12:31:16Z (GMT). No. of bitstreams: 1 lesemky.pdf: 1202883 bytes, checksum: f8220049d5a1bd344120a49c3ed2500a (MD5) Previous issue date: 2012-12-12 / Cytokeratin 19 (CK 19) is a molecular marker that express cell replication and differentiation, and HER-2 oncogene (Human Epidermal Growth factor receptor-Type 2) is the second member of the human epidermal growth factor receptor (EGFR) family. Its overexpression can mean aggressiveness and poor prognostic in various kinds of tumors, as breast, lung and prostate. In last few decades the diagnostic of morphological changes of the thyroid gland was increased. When being diagnosed with ultrasound, the thyroid nodule prevalence reaches 20% to 30% in the general population. The aim of this prospective study is verify the presence of these markers in thyroid glands in operated non-coastal Amazon inhabitants, and its relationship with pathologic findings. We selected 34 samples of formalin-fixed, paraffin-embedded thyroid tumor tissues, from patients treated at Hospital Adriano Jorge, Manaus, Amazonas. The patients consisted of six men and 28 women, aged between 25 and 76 years, average 47 years. The tissues corresponded to nine multinodular goiter (MNG), seven colloid goiters (CG), five nodular hyperplasia (NH) four adenomatous goiters (AG), three papillary thyroid microcarcinoma (PTMC) and five papillary thyroid carcinomas (PTC). Immunohistochemistry (IHC) staining with CK 19 and HER-2 were performed using the labeled streptavidin biotin peroxidase complex system (LSAB2, DAKO, USA) on all tissues using monoclonal antibodies BA17 mab mouse (Dako M0772, USA) and SP3 rabbit mab (Spring M3034, USA) and inferential statistical analysis applying (Fisher exact test with 5% significance level). HER-2 IHC was not found in all samples. We found a strong positive reactivity for IHC CK19 in all 3 patients with PTMC, in four with PTC, one with MNG, and one with CG. We found focal positivity for CK 19 in one PTC, two MNG, 4 CG and one AG. Statistical significance was found only between CK 19 and histopathology. The results suggest thats HER-2 oncogene has no predictive or prognostic value in thyroid tissues and CK 19 marker showed affinity for PTC, although it is also found in benign tissues with less intensity. / A citoqueratina 19 (CK 19) é um marcador molecular que expressa diferenciação e replicação celular e o oncogene HER-2 (Human Epidermal Growth factor receptor-Type 2), membro da família Fator de Crescimento Epidérmico Humano (EGFR), uma proteína que quando sobre-expressa pode significar maior ploriferação celular e agressividade em vários tipos de tumores, dentre eles mama, pulmão e próstata. Nas últimas décadas vêm aumentando o diagnóstico de alterações morfológicas da glândula tireoide, sendo que quando diagnosticado à ultrassonografia a prevalência do nódulo tireoideano chega a 20% a 30% na população geral. Objetivamos neste estudo prospectivo verificar a presença destes marcadores em glândulas tireoideas operadas em pacientes habitantes em região amazônica não litorânea, e sua relação com as alterações morfológicas encontradas. Foram selecionadas 34 amostras de tecido tireoidiano preservados em formol e armazenados em parafina, de pacientes operados na Fundação Hospital Adriano Jorge, de Manaus, Amazonas. Os pacientes corresponderam a seis homens e 28 mulheres, com idade entre 25 e 76 anos e média de 47 anos. Os tecidos corresponderam a nove bócios multinodulares (BMN), sete bócios coloides (BC), cinco hiperplasias nodulares (HN) quatro bócios adenomatosos (BA), três microcarcinomas papilíferos (MCP) e cinco carcinomas papilíferos da tireóide (CPT). Exames de imuno-histoquímica em busca dos marcadores CK19 e HER-2 foram realizados em todos os tecidos usando anticorpos monoclonais BA17 (mab rato, Dako M0772, EUA) e SP3 (policlonal em coelho, Spring M3034, EUA) e o método esteptavidina-biotina-peroxidade (Kit LSAB, Dako, EUA) e análise estatística inferencial aplicando o teste Exato de Fisher com nível de significância de 5%. Não foi encontrada positividade para o marcador HER-2 em tecidos tireoidianos malignos ou benignos. Foram encontrados positividade média a forte intensidade para CK19 em todos os três pacientes com MCP, quatro CPT, um BMN e um BC. Foram encontrados positividade focal em um CPT, dois BMN, quatro BC e um BA. A análise estatística demonstrou significância estatística somente entre as variáveis CK 19 e tipo histopatológico. Os resultados da amostra analisada demonstraram que a pesquisa no oncogene HER-2 não apresentou presença deste marcador em nenhum dos tecidos tireoidianos, e o marcador CK 19 foi presente em maior intensidade nos casos de Carcinoma que nos tecidos benignos onde foi encontrado.
25

Avaliação do perfil de expressão gênica de linhagens celulares do tecido mamário com diferentes níveis de expressão do receptor HER-2 tratadas com ácido docosahexaenoico / Evaluation of the gene expression profile of breast tissue cell lines with different expression levels of the HER-2 receptor treated with docosahexaenoic acid

Danielle Fontes de Almeida 03 May 2013 (has links)
O câncer de mama permanece como segundo tipo de câncer mais frequente no mundo e o primeiro entre as mulheres. Tumores de mama podem ser categorizados pela expressão de receptores como o HER-2 (receptor de fator de crescimento epidermal 2). A hiperexpressão do receptor HER-2 é observada em cerca de 30% dos carcinomas de mama, e está associada a prognósticos desfavoráveis. Os ácidos graxos poli-insaturados (AGPI) , como os ácidos graxos ômega-3, parecem diminuir o risco de câncer de mama. O ácido docosahexaenoico (DHA), um tipo de AGPI ômega-3 parece ter o maior potencial antitumoral no câncer de mama. Alguns mecanismos de ação foram propostos para a ação do DHA no controle do câncer de mama, no entanto, faltam dados para elucidar os mecanismos moleculares do DHA no tecido mamário normal e cancerígeno. Dessa maneira, o objetivo desse trabalho foi avaliar a ação do DHA na modulação da expressão de genes em linhagem celular normal (HB4a), transformada (HB4aC5.2) e de carcinoma mamário humano (SKBR-3). As linhagens estudadas foram tratadas com 100 ?M de DHA ou controle (etanol) durante 72 horas. Após a extração de RNA realizamos a técnica de expressão gênica global (Microarray) para encontrar os genes diferencialmente expressos, em relação ao tratamento com DHA, em cada linhagem celular estudada. Na linhagem normal (HB4a) observamos 174 genes diferencialmente expressos (p<0,01), sendo 136 hiperexpressos e 38 hipoexpressos, na linhagem celular transformada (HB4aC5.2) encontramos 208 genes diferencialmente expressos (p<0,01), sendo 32 hiperexpressos e 176 hipoexpressos. A linhagem do carcinoma mamário (SKBR-3) apresentou 126 genes diferencialmente expressos (p<0,01), sendo 48 hiperexpressos e 78 hipoexpressos. A análise ontológica destes genes permitiu identificar processos biológicos como: adesão celular, diferenciação celular e metabolismo lipídico. Concluímos que o DHA altera o perfil de expressão gênica de maneiras distintas em linhagem normal, transformada e de carcinoma mamário humano. Além disso, encontramos após o tratamento com DHA genes envolvidos com o metabolismo lipídico nas linhagens que hiperexpressam o receptor HER-2 / Breast cancer remains the second most common cancer in the world and first among women. Breast tumors can be categorized by the expression of receptors such as HER-2. Overexpression of HER-2 receptor is associated with unfavorable prognosis.The polyunsaturated fatty acids (PUFAs) omega- 3 appears to decrease the risk of breast cancer. Docosahexaenoic acid (DHA), a type of omega-3 PUFAs, seems to have greater antitumor potential in breast cancer. However, the gene expression profile resulting from the action of DHA in breast cancer has not been elucidated yet. We aimed to examine the effects of DHA on normal breast cell line (HB4a), transformed cell line (HB4aC5.2) and breast cancer cell line (SKBR-3) and using a microarray approach. Cells were treated with 100?M of DHA for 72 hours. We identified 174, 208 and 126 differentially expressed genes after DHA treatment, in HB4a, HB4aC5.2 and SKBR3, respectively. Notably, the molecular pathways for the differentially expressed genes included those related to lipid metabolism, cell growth, molecular transport and cell-to-cell signaling. Where found genes related to overexpression of HER-2 after treatment with DHA. These genes involved in lipid metabolism and were down-expressed after treatment, suggesting a possible mechanism DHA in breast cancer by lipid metabolism control
26

Radiosensitisation of low HER-2 expressing human breast cancer cell lines

Hamid, Mogammad Baahith 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Breast Cancer remains one of the world’s leading causes of cancer related deaths amongst women. Its treatment has evolved from invasive, highly toxic therapies to treatments that possess a higher specificity and a lower toxicity. Despite improvements in overall survival, many patients do not benefit from these agents because of acquired and/or inherent tumour resistance, which could hinder treatment efficacy. Novel treatment strategies are, therefore, warranted to address these challenges and to significantly improve patient responses. Inhibiting components of the HER-2 signalling pathway can significantly sensitise breast cancer cells to low doses of ionising radiation. The objective of this study was to inhibit key molecular targets of the human epidermal growth factor receptor 2 (HER-2) signalling pathway and expose breast cancer cell lines to doses of radiation, so as to establish potential therapeutic targets that may be amenable to combined modality therapy, and formulate a cocktail of inhibitors to evaluate its radiosensitising capability. This study found that pre-treatment of two breast cancer cell lines (MDA-MB-231 and MCF-7) with a HER-2 inhibitor (TAK-165) had little or no effect on radiosensitivity. However, a radiation enhancement was observed when these cells were pre-treated either with BEZ235, a dual inhibitor of phosphoinositide 3-kinase (PI3K) and mammalian target for rapamycin (mTOR), or a cocktail of TAK-165 and BEZ235. These findings suggest that concurrent inhibition of HER-2, PI3K and mTOR during radiotherapy might improve treatment response of breast cancer patients. / AFRIKAANSE OPSOMMING: Borskanker bly steeds een van die leidende oorsake van sterftes aan kanker in vrouens. Behandeling het vanaf ‘n ingrypende, hoogs toksiese terapie verander na ‘n regimen wat hoogs spesifiek met ‘n laer toksisiteit is. Nogtans trek baie pasiënte geen voordeel uit hierdie nuwe benadering nie, omdat inherente en/of verworwe tumorweerstand daarteen suksesvolle uitkomste verhoed. Nuwe behandelingstrategieë is dus nodig om hierdie uitdagings te bekamp en om resultate in pasiënte aansienlik te verbeter. Inhibisie van komponente van die HER-2-seinoordragkaskade kan borskankerselle gevoelig maak vir lae dosisse van geïoniseerde bestraling. Die doelwit van hierdie studie was om sleutelteikens in die HER-2- seinoordragkaskade te inhibeer en om borskankerselle daarna aan bestralings dosisse bloot te stel. Sodoende word potensiële terapeutiese teikens wat vatbaar is vir gekombineerde modaliteitsterapie geïdentifiseer, waarna ‘n kombinasie van inhibitore geformuleer en geëvalueer kan word ten opsigte van hulle kapasiteit om gevoeligheid vir bestraling te verhoog. Die studie bevind dat voorbehandeling met ‘n HER-2-inhibitor (TAK-165) van borskankersellyne (MDA-MB-231 en MCF-7) min of geen invloed gehad het op stralingsensitiwiteit nie. ‘n Stralingsversterking is egter geïdentifiseer toe die selle vooraf behandel is met óf BEZ-235, ‘n tweevoudige inhibitor van fosforinositied 3-kinase (PI3K) en soogdierteiken vir rapamisien (mTOR), óf ‘n mengsel van TAK-165 en BEZ-235. Hierdie bevindinge suggereer dat gelyktydige inhibisie van die HER-2- seinoordragkaskade, PI3K en mTOR gedurende stralingsterapie moontlik die uitkoms in borskankerpasiënte kan verbeter.
27

Radiolabeled HER-2 Binding Affibody Molecules for Tumor Targeting : Preclinical Studies

Steffen, Ann-Charlott January 2006 (has links)
<p>Conventional cancer treatment based on radiotherapy or chemotherapy affects all dividing cells. By directing the therapy specifically to the tumor cells, normal cells can be spared. Tumor targeting molecules carrying a cytotoxic moiety is then an attractive approach. </p><p>In this thesis, an affibody molecule with high affinity for the protein HER-2, that is strongly associated with aggressive forms of breast cancer, was selected. After radiolabeling with <sup>125</sup>I, the affibody molecule, in monovalent and bivalent form, was tested <i>in vitro</i> in HER-2 overexpressing tumor cells and in transplanted tumors in mice. </p><p>It was shown that the HER-2 targeting affibody molecule bound its target in a specific manner, both <i>in vitro</i> and <i>in vivo</i>. The small size of the affibody molecule resulted in fast clearance through the kidneys. An impressive tumor-to-blood ratio of 10 eight hours post injection was achieved and the tumors could easily be visualized in a gamma camera. </p><p>The biologic effects of the bivalent affibody molecule and a monovalent affinity maturated version was measured and compared with the effects of the monoclonal antibody trastuzumab. It was found that although all molecules target the same protein, the effects differed greatly.</p><p>The affibody molecule was also labeled with the alpha-emitting radionuclide <sup>211</sup>At. Specific decrease in survival was seen in HER-2 overexpressing cells receiving the <sup>211</sup>At labeled affibody molecule. The sensitivity to the treatment differed between cell lines, probably as a result of differences between the cell lines in internalization and nuclear size. The <sup>211</sup>At labeled affibody molecules were also tested <i>in vivo</i>, where stability of the <sup>211</sup>At label was a problem. To circumvent this problem, more stable conjugation chemistry was tested, as well as strategies to prevent uptake of released <sup>211</sup>At by normal organs.</p><p>This thesis describes the selection and optimization of affibody molecules for medical use for the first time.</p>
28

Predictive Factors in Esophageal Carcinoma

Dreilich, Martin January 2006 (has links)
<p>Esophageal carcinoma is a malignancy with a poor prognosis and is the sixth cause of cancer related death worldwide. In Sweden approximately 400 new cases are diagnosed every year. The aim of this present thesis was to investigate predictive factors for esophageal carcinoma patients.126 esophageal carcinoma patients admitted to the department of Oncology at the University Hospital in Uppsala between 1990-2000 were investigated with focus on known and potential prognostic factors. Performance status and stage of the disease were the only independent prognostic factors (p-values <0.001). </p><p>Angiogenic factors VEGF and bFGF were correlated to platelet and leukocyte counts and VEGF was correlated to tumor volume (p=0.04) whereas bFGF was not (p=0.08) in pre-treatment serum samples from 42 esophageal carcinoma patients. The use of the angiogenic factors as prognostic factors, prior to therapy in patients with esophageal carcinoma, according to the results from the present study, seems limited. </p><p>HER-2 overexpression was seen in 17% of 97 investigated esophageal tumor samples. In squamous cell carcinoma patients, HER-2 overexpression correlated with poorer survival (p=0.035), whereas in adenocarcinoma patients, HER-2 status did not. HER-2 overexpression seems to be associated with poorer survival in esophageal carcinomas, especially in patients with squamous cell esophageal carcinoma. </p><p>Telomerase activity was detected in all esophageal cell lines, with a broad range of activity levels. No correlation was found between telomerase activity levels and sensitivity to investigated cytotoxic drugs. We therefore conclude that basal telomerase activity level is not a key determinant of sensitivity to standard cytotoxic drugs in esophageal carcinoma cell lines. </p><p>The virus HPV-16 was detected in 16 % of the patients; no other type HPV was detected. HPV-16 infection had no significant effect on survival (p=0.72). Our results did not show that HPV-16 increases survival or improve therapy response in patients with esophageal carcinoma.</p>
29

Therapeutic peptidomimetic strategies for costimulation blockade in multiple sclerosis and transplantation / conformational peptide vaccines of the HER-2/neu dimerization loop are effective in inhibiting mammary tumor growth in vivo

Allen, Stephanie D. January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 90-112).
30

Radiolabeled HER-2 Binding Affibody Molecules for Tumor Targeting : Preclinical Studies

Steffen, Ann-Charlott January 2006 (has links)
Conventional cancer treatment based on radiotherapy or chemotherapy affects all dividing cells. By directing the therapy specifically to the tumor cells, normal cells can be spared. Tumor targeting molecules carrying a cytotoxic moiety is then an attractive approach. In this thesis, an affibody molecule with high affinity for the protein HER-2, that is strongly associated with aggressive forms of breast cancer, was selected. After radiolabeling with 125I, the affibody molecule, in monovalent and bivalent form, was tested in vitro in HER-2 overexpressing tumor cells and in transplanted tumors in mice. It was shown that the HER-2 targeting affibody molecule bound its target in a specific manner, both in vitro and in vivo. The small size of the affibody molecule resulted in fast clearance through the kidneys. An impressive tumor-to-blood ratio of 10 eight hours post injection was achieved and the tumors could easily be visualized in a gamma camera. The biologic effects of the bivalent affibody molecule and a monovalent affinity maturated version was measured and compared with the effects of the monoclonal antibody trastuzumab. It was found that although all molecules target the same protein, the effects differed greatly. The affibody molecule was also labeled with the alpha-emitting radionuclide 211At. Specific decrease in survival was seen in HER-2 overexpressing cells receiving the 211At labeled affibody molecule. The sensitivity to the treatment differed between cell lines, probably as a result of differences between the cell lines in internalization and nuclear size. The 211At labeled affibody molecules were also tested in vivo, where stability of the 211At label was a problem. To circumvent this problem, more stable conjugation chemistry was tested, as well as strategies to prevent uptake of released 211At by normal organs. This thesis describes the selection and optimization of affibody molecules for medical use for the first time.

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