Linfomas representam um grupo de neoplasias que tem em comum a origem em células linforreticulares, manifestando-se geralmente em tecidos linfóides. Em sua evolução há uma reação generalizada contra as alterações sistêmicas que comprometem a homeostase, conhecida como resposta de fase aguda. Citocinas são proteínas relacionadas à imunidade inata e adquirida que medeiam diversas funções e estão envolvidas na resposta inflamatória e são produzidas em resposta a vários estímulos. Foram objetivos desse estudo, verificar se existem diferenças no perfil das citocinas interleucina-2, interleucina-6, interleucina-10, MCP-1 e TNF-alfa nos animais com linfoma multicêntrico ao diagnóstico, quando comparados a um grupo controle e verificar se existe diferença entre os níveis apresentados no momento do diagnóstico e na 6ª semana, momento em que se avalia a remissão. Os grupos do estudo foram constituídos por 20 cães com linfoma (experimental) e 19 cães clinicamente normais (controle) sendo excluídos do estudo cães que apresentavam tratamento prévio e/ou doença concomitante. A quantificação das variáveis estudadas foi realizada utilizando-se kit comercial CCYTOMAG 90K (Milliplex®), sendo as mesmas determinadas no grupo controle uma única vez e no grupo experimental, quando do diagnóstico e na 6ª semana de tratamento. A análise estatística foi realizada através de teste não paramétrico de Mann-Whitney não pareado para o grupo controle e diagnóstico, bem como o diagnóstico e a 6ª semana de tratamento, enquanto que a análise de variância simples (ANOVA) não paramétrico Kruskal-Wallis foi aplicada na comparação dos três grupos (controle, ato do diagnóstico e 6ª semana de tratamento) para todas as citocinas. Foi observada diferença significante nos níveis de IL-10 entre o grupo controle e o experimental ao diagnóstico (p= 0,0033). Os valores do grupo linfoma ao diagnóstico foram elevados em relação ao controle, sem diferença significante entre os momentos do diagnóstico e 6ª semana. As IL-2 e IL-6 mostraram diferenças significantes entre o grupo controle e o grupo linfoma ao diagnóstico (p= 0,0037 e p=0,0017, respectivamente), mas os valores do controle apresentaram-se elevados em relação ao momento do diagnóstico e não houve diferença entre o diagnóstico e 6ª semana. As citocinas TNF-α e MCP-1 não apresentaram diferença significativa. Concluiu-se que os animais com linfoma no diagnóstico apresentaram níveis séricos mais elevados de IL-10, quando comparados ao diagnóstico e ao grupo controle e seus níveis mantiveram-se elevados na 6ª semana de tratamento. As concentrações de IL-2 e IL-6 estiveram mais elevadas no grupo controle quando comparadas aos animais do grupo experimental e as concentrações de TNF-α e de MCP-1 não apresentaram diferença significativa / Lymphomas belongs to a group of malignancies that have in common the origin in lymphoreticular cells, and is generally manifested in lymphoid tissues. In its evolution there is a generalized reaction against the systemic changes that compromise the homeostasis, known as acute phase response. Cytokines are proteins related to innate and acquired immunity which mediate several functions and are involved in inflammatory response and produced in response to several stimulant. This study was designed to verify if there are differences in the profile of cytokines interleukin-2, interleukin-6, interleukin-10, MCP-1 and TNF-alpha in dogs with multicentric lymphoma when compared to a control group and see if there is difference between the levels at the time of diagnosis and at the 6th week, when remission is achieve. The study group consisted of 20 dogs with lymphoma (experimental) and 19 clinically healthy dogs (control). We excluded patients who had previous treatments and/ or concomitant disease. For measurements of cytokines we use a commercial kits CCYTOMAG 90K (Milliplex®), the same being determined in the control group only once and in the experimental group at diagnosis and at 6 week of treatment. Statistical analysis was performed using nonparametric Mann-Whitney unpaired test for the control group and diagnosis, and the diagnosis and 6 week of treatment, while the simple analysis of variance (ANOVA) nonparametric Kruskal-Wallis test was applied when comparing the three groups (control, diagnosis and act 6th week of treatment) for all cytokines. There was a significant difference in IL-10 levels between the control group and the experimental diagnosis (p = 0.0033). The values of the lymphoma group at diagnosis were higher than the control, without significant difference between the time of diagnosis and 6th week. IL-2 and IL-6 showed significant differences between the control and lymphoma groups at diagnosis (p = 0.0037 and p = 0.0017, respectively), but the control had higher levels than the lymphoma group and there was no difference between diagnosis and 6th week. The TNF-α and MCP-1 cytokines showed no significant difference. It was concluded that animals with lymphoma had higher serum levels of IL-10 when compared to control and their levels remained high at 6 weeks of treatment. IL-2 and IL-6 concentrations were higher in the control group compared to lymphoma group and the concentrations of TNF-α and MCP-1 were not significantly different

Linfomas são as neoplasias hematopoiéticas mais comumente relatadas em cães, podendo ocorrer em qualquer idade. A etiologia ainda é desconhecida, porém se aceita que seja multifatorial. São classificadas de acordo com sua localização anatômica, estadio clínico da Organização Mundial de Saúde (OMS), critérios cito-histológicos e imunofenotípicos. A anemia é a anormalidade hematológica mais observada em pacientes com câncer e manifesta-se em cerca dois terços dos cães com linfoma. Os radicais livres de oxigênio produzidos pelas células tumorais aumentam o estresse oxidativo, sendo este demonstrado por mudanças na atividade das enzimas antioxidantes, podendo ocorrer oxidação de proteínas de DNA, aumento da peroxidação de lipídeos e alterações da fragilidade osmótica eritrocitária, acarretando a diminuição da meia vida das hemácias e, sendo essa diminuição um dos fatores que pode levar à anemia nos casos de linfoma. A superoxido dismutase (SOD) é uma enzima antioxidante que catalisa a dismutação do radical superóxido em oxigênio e peróxido de hidrogênio, protegendo as células dos danos induzidos por estes radicais livres. O objetivo deste estudo foi determinar as concentrações eritrocitárias de superóxido dismutase, além de substâncias reativas ao ácido tiobarbitúrico (MDA), o estado antioxidante total (TAS) e a fragilidade osmótica eritrocitária, em cães hígidos e com linfoma multicêntrico com e sem anemia, para avaliar a influência desses mecanismos no desenvolvimento das anemias associadas a essa neoplasia. Amostras de sangue foram obtidas de 24 cães com linfoma multicêntrico, sendo 10 sem anemia e 14 com anemia, e 20 cães saudáveis. Foi observada diferença significante no estado antioxidante total entre os grupos controle, grupos experimentais com linfoma multicêntrico com anemia e sem anemia (p < 0,0001). Não houve diferença significante quando os cães com linfoma com anemia e sem anemia foram comparados, assim como na avaliação das concentrações plasmáticas do MDA entre o grupo controle, grupo experimental com linfoma multicêntrico com anemia e grupo experimental com linfoma multicêntrico sem anemia (p = 0,823). A diferença também não foi significante quando se comparou o grupo controle e o grupo dos animais doentes (p=0,671). A diferença não foi significante na avaliação das concentrações eritrocitárias de superoxido dismutase entre o grupo controle, grupo experimental com linfoma multicêntrico com anemia e grupo com linfoma multicêntrico sem anemia (p=0,0748.). Entretanto, foi observada diferença significante entre o grupo controle e o grupo experimental com linfoma multicêntrico (p=0,0168). Não foi observada diferença na fragilidade osmótica eritrocitária dos cães com linfoma multicêntrico com anemia e sem anemia, as concentrações de NaCl em que observou-se 50% de hemólise estavam dentro dos valores postulados por Jain, 1963. Os resultados obtidos indicam um aumento do estresse oxidativo em cães com linfoma e que a anemia observada nos pacientes com linfoma não esta relacionada diretamente a diminuição das defesas antioxidantes eritrocitárias ou à alterações nas propriedades de membrana secundarias a peroxidação lipídica, que poderiam interferir na fragilidade do eritrócito / Lymphoma is hematopoietic malignancies most commonly reported in dogs can occur at any age. The etiology is still unknown, but is accepted to be multifactorial. They are classified according to their anatomic location, clinical stage of the World Health Organization (WHO), cytological and histological criteria and immunophenotype. Anemia is the most commonly observed hematologic abnormalities in patients with cancer and manifests itself in about two thirds of dogs with lymphoma. The oxygen free radicals produced by tumor cells increases oxidative stress, which is demonstrated by changes in antioxidant enzyme activities, protein and DNA oxidation, increased lipid peroxidation and alterations of erythrocyte osmotic fragility, leading to a decrease in half life of red blood cells and this decrease is one factor that can lead to anemia in cases of lymphoma. The superoxide dismutase (SOD) is an antioxidant enzyme that catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide, protecting cells from damage induced by these free radicals. The aim of this study was to determine erythrocyte superoxide dismutase, and thiobarbituric acid reactive substances (MDA), total antioxidant status (TAS) and erythrocyte osmotic fragility, and in healthy dogs with multicentric lymphoma with and without anemia, to evaluate the influence of these mechanisms in the development of anemia associated with this neoplasia. Blood samples were obtained from 24 dogs with multicentric lymphoma, 10 and 14 with anemia without anemia and 20 healthy dogs. Significant difference was observed in total antioxidant status between the control group, experimental groups with multicentric lymphoma with anemia and without anemia (p <0.0001). There was no significant difference when dogs with lymphoma with anemia and without anemia were compared no significant difference in assessment of plasma concentrations of MDA between the control group, experimental group with multicentric lymphoma with anemia and experimental group with multicentric lymphoma without anemia (p=0.823). The difference was not significant when comparing the control group and the group of sick animals (p = 0.671). The difference was not significant in the evaluation of erythrocyte superoxide dismutase concentrations between the control group, experimental group with multicentric lymphoma with anemia and patients with multicentric lymphoma without anemia (p = 0.0748).. However, significant difference was observed between the control and experimental group with multicentric lymphoma (p = 0.0168). No difference was observed in erythrocyte osmotic fragility of dogs with multicentric lymphoma with anemia and without anemia, the concentrations of NaCl in which there was 50% hemolysis were within the range postulated by Jain, 1963. The results indicate an increased oxidative stress in dogs with lymphoma and that the anemia observed in patients with lymphoma is not directly related to the decrease in erythrocyte antioxidant defenses or the changes in properties of secondary membrane lipid peroxidation, which could interfere with the fragility of erythrocyte

Nós avaliamos a utilidade de um painel de anticorpos constituído por CD5, CD10, CD23, CD43, bcl-2 e ciclina D1 na classificação de 134 linfomas de pequenas células B. O CD10, positivo nos linfomas foliculares, o CD23, positivo nos linfomas linfocíticos/LLC, e a ciclina D1, expressa nos linfoma do manto, foram os que mais contribuíram na diferenciação destes linfomas, firmando o diagnóstico em 88,1% dos casos. A ausência de aspecto nodular e de células dendríticas, e a presença de centros de proliferação diferencia o linfoma linfocítico/LLC dos outros tipos. A expressão de proteína p53 e de antígeno Ki-67 > 20% foi associada com tempo de sobrevida menor, principalmente no linfoma do manto / We evaluated the usefulness of a panel of antibodies comprising CD5, CD10, CD23, CD43, bcl-2 and cyclin D1 in the classification of 134 small B-cell lymphomas. CD10, positive in follicular lymphomas, CD23, positive in lymphocytic lymphoma/CLL and cyclin D1 expressed in mantle cell lymphoma were the ones that contributed the most in the differentiation of these lymphomas, confirming the diagnosis in 88.1% of the cases. The absence of nodular aspect and dendritic cells and the presence of proliferation centers differentiate the lymphocytic lymphoma/CLL from the other types. The expression of p53 protein and Ki-67 > 20% was associated to a shorter survival, especially in mantle cell lymphoma

Os linfonodos podem ser compreendidos como estruturas integrantes de dois sistemas orgânicos, o circulatório e o imunológico, apresentando estrutura mutável decorrente do tipo, da intensidade e do tempo da estimulação antigênica. As doenças nodais são complexas devido ao grande número de agentes que atingem os linfonodos via linfa e por causa da complexidade inerente do sistema imunológico e suas doenças próprias. A linfadenopatia é um achado clínico muito comum em cães, e o seu significado não deve ser desprezado. Inúmeros processos patológicos são observados no linfonodo canino, particularmente as hiperplasias reacionais benignas, linfadenites e os linfomas, e a sua total compreenção requer o conhecimento de histofisiologia, noções de imunologia, e biologia molecular. O conhecimento dos métodos diagnósticos disponíveis tem fundamental importância para o manejo do paciente, permitindo um tratamento acurado e eficiente / The lymph nodes may be known as integrants of two organic systems, circulatory and immunological, demonstrating mutable structure depending on the type, intensity, and time of antigenic stimulation. Nodal diseases are complex, because of the large number of diseases reaching nodes via lymph and because of the inherent complexity of the immune system and its own diseases. Lymphadenopathy is a common clinical finding, Many pathological processes has been found in canine lymph nodes, primarily benign reative hiperplasia, lymphadenitis and lymphomas, and your complete comprehension requires knowledge in histophysiology, immunology notions, and molecular biology. An understanding of the available diagnostic methods has fundamental importance for patient management, allowing an accurate and efficient treatment

Linfoma é uma neoplasia maligna originária dos linfócitos. Podem atingir regiões nodais e extranodais, este último ocorrendo mais comumente em casos de linfoma não-Hodking (LNH) e raramente em linfomas de Hodking (LH). Na cavidade oral, o linfoma é classificado como a terceira neoplasia mais comumente encontrada depois do Carcinoma epidermóide e tumores de glândula salivar. O linfoma difuso de grandes células B (LDGCB) é o subtipo mais comum de LNH na cavidade oral, e ocorre mais comumente em região do palato e gengiva marginal. O diagnóstico do linfoma requer um estudo imuno-histoquímico, incluindo anticorpos específicos para maior precisão. O presente trabalho fez um levantamento de todos os casos de linfoma oral diagnosticados no Serviço de Patologia Cirúrgica da FOUSP de maneira retrospectiva no período de 1997 a 2017. Foram analisadas as fichas de pedido de exame e diagnóstico histopatológico. Através da coleta de dados foi possível a visualização do perfil dos casos presentes e de um painel imuno-histoquimico mínimo encontrados no acervo da Faculdade de Odontologia da USP. Concluímos que em um laboratório de patologia Oral com recursos limitados, os anticorpos LCA, CD20, CD3 e Plasma cell são de grande valia para diagnosticar a maior parte dos principais linfomas que acometem a cavidade oral. / Lymphoma is a malignant neoplasm originating from lymphocytes. They may reach nodal and extranodal regions, the latter occurring most commonly in cases of non-Hodgkin\'s lymphoma (NHL) and rarely in Hodgkin\'s lymphoma (LH). In the oral cavity, lymphoma is classified as the second neoplasm most commonly found after spinous-cell carcinoma. Diffuse large B-cell lymphoma (LDGCB) is the most common subtype of NHL in the oral cavity, and occurs mostly in the palate and marginal gingiva. Diagnosis of lymphoma requires an immunohistochemical study, including specific antibodies for greater accuracy. The present study made a survey of all cases of oral lymphoma diagnosed in the Department of Surgical Pathology of FOUSP, retrospectively, in the period from 1997 to 2017. The files of the application for examination and histopathological diagnosis were analyzed. Through the collection of data it was possible to visualize the profile of the present cases and a minimal immunohistochemical panel found in the collection of the Faculty of Dentistry of USP. We conclude that in an oral pathology laboratory with limited resources, the LCA, CD20, CD3 and Plasma cell antibodies are of great value to diagnose some of the main lymphomas that affect the oral cavity.

Pacientes com linfoma de Hodgkin (LH) tratados com poliquimioterpia com adriamicina, bleomicina, vincristina e doxorrubicina (ABVD) apresentam resposta terapêutica distinta. Para aprimorar a avaliação prognóstica e a abordagem terapêutica em LH objetivamos avaliar o valor prognóstico da PET-FDG após 2 ciclos de ABVD (PET2) em pacientes com LH. Foram incluídos nesse estudo prospectivo 115 pacientes com diagnóstico recente de LH no período de agosto de 2005 a dezembro de 2007. Os pacientes foram estadiados com exame clínico, laboratorial, tomografia computadorizada e PET-FDG (PET0). Todos os pacientes foram tratados com ABVD e aqueles com massa tumoral extensa foram tratados com radioterapia associada. Após dois ciclos de ABVD os pacientes foram submetidos a PET2. Nenhum tratamento foi alterado baseado na PET2. Foi avaliado o valor prognóstico dos fatores clínicos, Índice Prognóstico Internacional (IPI) e PET2 em relação à sobrevida livre de eventos (SLE) em três anos. Dos 104 pacientes que foram avaliados, 82 atingiram remissão completa e 22 pacientes apresentaram falha de tratamento durante a mediana de 36 meses de acompanhamento. A SG e SLE em três anos foi de 94,2% e 74,2% respectivamente. A SLE em três anos da PET2 positiva foi de 54,3%, enquanto da PET2 negativa foi de 90,5% (p< 0.001). Na análise de subgrupos de pacientes com estádio precoce, avançado, IPI baixo e alto risco, a PET2 também apresentou correlação estatisticamente significativa com o prognóstico. Concluímos que a PET2 é o melhor fator prognóstico independente na avaliação de pacientes com LH / Patients with Hodgkin lymphoma (HL) treated with poliquimioteraphy with adriamycin, bleomycin, vincristine and doxorubicin (ABVD) have distinct therapeutic response. In order to improve the prognostic assessment and therapeutic approach in HL we have evaluated the prognostic value of FDG-PET after 2 cycles of ABVD (PET2). Were included in this prospective study 115 patients with newly diagnosed LH in the period of August 2005 to December 2007. The patients were staged with physical examination, laboratory, CT and PET-FDG (PET0). All patients were treated with ABVD and those with extensive tumor were treated with radiotherapy associated. After two cycles of ABVD patients underwent PET2. No treatment was changed based on PET2. We assessed the prognostic value of clinical factors, international prognostic score (IPS) and PET2 in relation to event-free survival (EFS) in three years. Of the 104 patients who finalized the evaluation, 82 achieved complete remission and 22 patients experienced treatment failure during the median of 36 months of follow-up. The EFS at three years was 74.2%. EFS in three years of PET2 positive was 54.3%, while the PET2 negative was 90.5% (p <0.001). In subgroup analysis of patients with early stage, advanced, low and high risk IPS, PET2 also showed significant correlation with the prognosis. We conclude that the PET2 is the best independent prognostic factor in the evaluation of overall patients with LH, or in subgroups of early, advance; low and high risk of HL

Apoptosis is a cell death pathway that regulates tissue homeostasis, and is often altered in oncogenesis. Autophagy is a lysosome degradation pathway that mediates cellular adaptation in response to stresses. Altered autophagy pathways are proposed to be associated with pathogenesis of neurodegenerative diseases and oncogenesis. The goal of this work is to study the complex link between apoptosis and autophagy pathways, and their possible roles in the development of cancer. Using transgenic mice models, we found that impaired apoptosis by overexpression of a dominant negative form of Caspase-9 (Casp9DN) failed to accelerate T-cell lymphoma either by itself or in tumor-prone Bax overexpressing transgenic mice. Additionally, heterozygous disruption of Beclin 1, a central upstream autophagy regulator, failed to promote T-cell lymphoma in either Casp9DN or tumor-prone Bax overexpressing transgenic mice. However, caspase inhibition enhanced a unique form of selective mitochondrial autophagy, referred to as mitochondrial outer membrane permeabilization (MOMP)-induced mitophagy. Parkin, a protein mutated in early-onset Parkinson's disease, mediates mitophagy following protonophore (CCCP) treatment, suggesting that Parkin may also play a role in MOMP-induced mitophagy. Thus, two different types of mitochondrial stresses, MOMP and CCCP, cause mitochondrial depolarization and induce mitophagy. We therefore examined if there is a mechanistic link between two mitophagy pathways. Focusing on the roles of autophagy and apoptosis regulators using isogenic hematopoietic cell lines, our studies demonstrate that MOMP-induced mitophagy is dependent upon Bcl-2 family members, but independent of Parkin or ULK1 (an autophagy regulator). In contrast, CCCP-induced mitophagy is dependent upon Parkin and ULK1, but independent of Bcl-2 family members. However, we found that both pathways ultimately result in the following properties: reduced mitochondrial respiration rate, altered cellular metabolism, and high sensitivity to 2-DG (an inhibitor of glycolysis). Interestingly, 2-DG induced cell death in cells following Parkin-dependent mitophagy is independent of Bcl-2 and Bax/Bak. Overall, the work in this dissertation demonstrates that the two different mitochondrial stresses, MOMP and protonophore (CCCP) treatment, lead to two mechanistically distinct mitophagy pathways, but both alter mitochondrial respiration and cellular metabolism.

Manganese superoxide dismutase (MnSOD), is a mitochondria-localized antioxidant enzyme that scavenges superoxide anions generated in the respiratory chains, has been known to play an important role in the radioprotection, and function as a tumor suppressor gene in many types of cancer. Sirtuin 3 (Sirt3) is a mitochondrial NAD+-dependent deacetylase that regulates mitochondrial oxidative metabolism, MnSOD activity, and tumorigenesis. The current study was designed to examine the role of MnSOD and Sirt3 in regulating mitochondrial metabolism and steady-state levels of O2*- in thymocyte responses to ionizing radiation (IR) and lymphomagenesis. Loss of MnSOD in thymocytes resulted in the decreased levels of viability when mice were exposed to 0.1 or 1 Gy 137Cs radiation. In contrast, loss of Sirt3 did not affect thymocyte radiosensitivity or radiation-induced superoxide levels when mice were exposed to a single dose of 137Cs radiation (0.1 or 1 Gy). Interestingly, the Sirt3-/- thymocytes demonstrated a compromised ability to induce an adaptive response following whole body exposure to a 0.1 Gy dose of 137Cs radiation when challenged 4 h later with a 1.5 Gy dose of 137Cs radiation. Of note, both Sirt3-/- and MnSOD-/- thymocytes did not demonstrate increased T cell lymphoma in C57BL/6 mice at 15-18 months following low dose (0.1 Gy or 1 Gy) radiation exposure to low linear energy transfer (LET) 137Cs or high LET 300 MeV/n Silicon (67 kev/µM) irradiation. Interestingly, the loss of Sirt3 in Bax overexpressing transgenic thymocytes did cause significant alterations in mitochondrial oxidative metabolism including increased levels of superoxide, increased mitochondrial membrane potential, and increased oxygen consumption, as well as decreased levels of MnSOD activity and decreased steady-state levels of ATP. Sirt3 was also found to be upregulated in Lck-Bax transgenic pre-malignant thymocytes, and downregulation of Sirt3 was noted in lymphomas from Lck-Bax mice. Furthermore, a significant acceleration of thymic lymphoma development was observed in Lck-Bax transgenic animals lacking Sirt3. In conclusion, the data presented here support the hypothesis that increased levels of superoxide in thymocytes induced by loss of Sirt3 or MnSOD and/or exposure to low dose radiation was not sufficient to induce T cell lymphomas. However, loss of Sirt3 significantly accelerated thymic lymphoma formation induced in Lck-Bax overexpressing C57BL/6 mice, showing that Sirt3 could act as a tumor suppressor in this model system. These results also support the speculation that mitochondrial oxidative metabolism regulated by Sirt3 leads to increased steady-state levels of O2*- and may contribute to the promotion of carcinogenesis in the Lck-Bax model of T cell lymphoma development.

<p>The Notch signalling pathway is an evolutionary conserved pathway, named after the Notch receptors, Notch1-4 in mammals, which upon cell-cell contact and ligand binding releases the intracellular domain (NICD). NICD translocates into the nucleus where it binds the transcriptional repressor RBP-Jk, which together with co-activators belonging to the Mastermind-like family of proteins form a transcriptional activation complex. This complex activates genes controlling cell fate decision, embryonic development, proliferation, differentiation, adult homeostasis and stem cell maintenance. On the other hand, disrupted Notch signalling may result in pathological conditions like cancer, although the mechanisms behind the disruption are often complex and in many cases largely unknown.</p><p>Notch1 drives the lymphocyte differentiation towards a T-cell fate and activating mutations in the gene have been suggested to be involved in T-cell lymphoma. In <em>paper I, </em>genetic alterations in <em>Notch1 </em>and the Notch1 regulating gene <em>CDC4 </em>were investigated in tumours from murine T-cell lymphoma induced with phenolphthalein, 1,3-butadiene or 2’,3’-dideoxycytidine. We identified activating <em>Notch1</em> mutations in 39% of the lymphomas, suggesting that <em>Notch1 </em>is<em> </em>an important target gene for mutations in chemically induced lymphomas.<em></em></p><p>While it is known that constitutively activated Notch signalling has a clear oncogenic function in several solid malignancies as well, the molecular mechanisms are less known in this context. Unpublished data of our lab, together with other recent studies, suggest that mutations of Notch and Notch-related genes <em>per se</em> are uncommon in solid malignancies including colorectal cancer, while a growing body of evidence indicates that aberrant Wnt/b-catenin signalling may result in pro-tumoural Notch activation in these contexts. In <em>paper II</em>, we therefore investigated potential transcriptional interactions between the Notch and Wnt signalling pathways in colorectal cancer cell lines. The proximal Notch and Wnt pathway gene promoters were bioinformatically identified and screened for putative TCF/LEF1 and RBP-Jk sites. In canonical Wnt signalling, Apc negatively regulates b-catenin leading to repression of TCF/LEF1 target genes. Upon repression of the Wnt pathway we observed that several genes in the Notch pathway, including <em>Notch2</em>, were transcriptionally downregulated. We also confirmed binding of Lef1 to <em>Notch2</em> as well as other Notch pathway gene promoters and luciferase assays showed an increased activity for at least one LEF1/TCF-site in the <em>Notch2</em> promoter upon co-transfection of HT29 or HCT116 cells with mutated b-catenin. HT29 cell lines were also treated with the g-secretase inhibitor DAPT, leading to inactivation of the Notch pathway by preventing release of NICD. However, results showed no effects on Apc, b-catenin or their target <em>cyclin D1</em>. Taken together, these results indicate that the Wnt pathway may function as a regulator of the Notch pathway through the TCF/LEF1 target gene program in colon cancer cell lines.</p><p>In summary, Notch pathway deregulation is of importance in both murine T-cell lymphoma and human colorectal cancer, although the mechanisms differ. The current results give new insights in Notch pathway alterations as well as the signalling networks in which the Notch pathway interacts, and thus increase the understanding of Notch’s involvement in malignant diseases.</p> / Studies on molecular genetic alterations in colorectal cancer

<p>The relationship between Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) is not entirely elucidated and a clonal relation may be present more often than previously believed. Mechanisms of tumour progression and resistance to therapy are poorly understood.</p><p>Between 1974 and 1994 all individuals in Sweden with both HL and NHL were identified. Thirty-two cases were studied using clinical, histopathological and immunohistochemical methods. The second lymphoma often appeared in an aggressive clinical form and a significant correlation between the expression of p53 and LMP-1 in the first and second lymphoma was demonstrated.</p><p>The treatment outcome for 307 patients with advanced stages of HL, in an unselected population was in accordance with the treatment results of large centres world-wide. Some patients were successfully selected for a shorter chemotherapy-regimen without inferior treatment results.</p><p>In 124 patients with relapse, the survival of those primarily treated with radiotherapy according to the National guidelines was in accordance with the survival of patients of initially advanced stages. A worse outcome was found for those who received both chemotherapy and radiotherapy initially, probably because of a higher frequency of bulky disease in this group. </p><p>Immunohistochemical analysis of the tumour suppressor protein p53 and retinoblastoma protein (Rb) of paired samples at diagnosis and at relapse in 81 patients did not reveal any specific staining pattern affecting survival.</p><p>A novel B-cell line (U-2932) was established from a patient with a diffuse large B-cell lymphoma previously treated for advanced stage and subsequent relapses of HL. An identical rearranged IgH gene was demonstrated in tumour cells from the patient and in U-2932. A p53 point mutation was detected and over-expression of the p53 protein was found. A complex karyotype with high-level amplifications of the chromosomal regions 18q21 and 3q27, i.e. the loci for <i>bcl-2</i> and <i>bcl-6</i> were demonstrated. </p>