Many cancers, including lymphoma, are associated with increased numbers of T cells with suppressive properties, and it has been suggested that immune subversion is important in cancer pathogenesis. The ability of lymphoma cells to induce conventional CD25- T cells to adopt a regulatory phenotype was evaluated, with the aim of elucidating the factors and pathways governing this process and determining the clinical relevance. Regulatory T cell phenotype in both peripheral blood and nodal material from patients with lymphoma and healthy controls was also assessed. Preferential representation of Tregs in nodal tissue was noted with higher percentages seen than in peripheral blood. Contrary to previous studies, minimal evidence to suggest that lymphoma induces a regulatory phenotype from CD4+CD25- T cells was found. Furthermore, nodal Tregs displayed high expression of Helios and FOXP3, indicating a thymically-derived rather than induced origin. PD-1 expressing T cells were present in greater numbers in PBMCs from patients compared with healthy controls, suggesting an alternative reason for the immunosuppression that may be exhibited in these patients. These data support recruitment and amplification as the mechanism for the high proportion of Tregs seen in lymphoma. Hodgkin lymphoma is typified by a prominent reactive infiltrate and is the archetype of immune subversion in lymphoma. Inherited predisposition is demonstrated through familial and twin studies. Susceptibility loci have been identified in a number of genes that affect immune response, with the strongest association seen with the HLA region. 5 individuals with classical Hodgkin lymphoma from a family originating in North East Scotland were evaluated by linkage analysis and exome sequencing. Novel, shared variants predicted to disrupt protein function were identified in 2 genes on chromosome 3. Proximity to a previously described gene in familial Hodgkin lymphoma implicates this region as an important susceptibility locus.

Orientador: Mirela Tinucci-Costa / Banca: Erika Maria Terra / Banca: Felipe Augusto Ruiz Sueiro / Resumo: A expectativa de vida dos cães está aumentando e com isso, o diagnóstico de diferentes neoplasias, particularmente os linfomas, um dos tipos tumorais mais prevalentes. O prognóstico desses pacientes tem se pautado nas avaliações clínicas, laboratoriais e de imagem, as quais podem não indicar a presença da doença em início de curso. Com este estudo, objetivou-se avaliar a eficácia de marcadores sorológicos para melhor estabelecer o prognóstico de cães com linfoma cutâneo e multicêntrico. Foram realizadas dosagens do receptor solúvel de Interleucina 2 (sIL 2R) no soro de 9 cães sadios (grupo 1), 20 cães com linfoma cutâneo (grupo 2) e 9 cães com linfoma multicêntrico (grupo 3), e do Antígeno do câncer 125 (CA 125) em 14 cães sadios (grupo 4), 13 cães com linfoma cutâneo (grupo 5) e 11 cães com linfoma multicêntrico (grupo 6). Adicionalmente foram avaliados os tempos de sobrevida, os resultados de exames hematológicos e de imagem dos pacientes, os quais foram relacionados com as concentrações séricas dos marcadores sorológicos. Os resultados mostraram que não houve diferença estatística (p > 0,05) entre as dosagens dos marcadores sIL 2R nos grupos 1, 2 e 3 e de CA 125 entre os grupos 4, 5 e 6. Houve diferença (p < 0,05) entre os grupos 2 e 5 (linfoma cutâneo) e 3 e 6 (linfoma multicêntrico) em relação ao tempo de sobrevida, o qual foi menor nos animais diagnosticados com linfoma cutâneo. Em relação às contagens hematológicas, apenas o linfócitos diferiram entre os grupos 2 e 3 (... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The life expectancy of dogs is increasing and with that the diagnosis of different neoplasms, particularly the lymphomas, one of the more prevalent tumor types. The prognosis of these patients has been based on clinical, laboratory and imaging evaluations, which may not indicate the diagnosis at the initial stages of the disease. The aim of this study was to evaluate the efficacy of serological markers to better predict the prognosis of dogs with cutaneous and multicentric lymphoma. Serum level of the soluble Interleukin 2 receptor (sIL 2R) were performed in 9 healthy dogs (group 1), 20 dogs with cutaneous lymphoma (group 2) and 9 dogs with multicentric lymphoma (group 3), and the cancer antigen 125 (CA 125) in 14 healthy dogs (group 4), 13 dogs with cutaneous lymphoma (group 5) and 11 dogs with multicentric lymphoma (group 6). In addition, survival times, hematological tests and imaging exams of oncological patients were performed to better evaluate the aggressiveness of the neoplasms and to correlate these results with the dosed serum markers. The results showed that there was no statistical difference (p > 0.05) in the dosages of sIL 2R between groups 1, 2 and 3 and CA 125 between groups 4, 5 and 6. There was difference (p < 0,05) between the groups 2 and 5 (cutaneous lymphoma) and 3 and 6 (multicentric lymphoma) in relation to the survival time, which was lower in the animals diagnosed with cutaneous lymphoma. In relation to hematological counts, only lymphocytes counts d... (Complete abstract click electronic access below) / Mestre

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Diagnostic Radiology / Master / Master of Philosophy

published_or_final_version / Medicine / Master / Master of Medical Sciences

NK-cell malignancies (NKLL) consist of two separate entities: Extranodal NK-cell lymphoma, nasal type (ENKL) and aggressive NK-cell leukemia (ANKL). ENKL is the second most common group of extranodal lymphomas in Hong Kong. Deletions in the 6q21 region in ENKL have been consistently reported in the literature and differential expression data indicated that the transcription factor PRDM1 (PR domain containing 1, with ZNF domain) located at 6q21-q22.1 is a candidate TSG in NK-cell neoplasms. PRDM1 exists as 2 isoforms generated from the same gene by alternative transcription promoter. PRDM1- differs from PRDM1-βin that it lacks the amino-terminal 101 amino acids with a disrupted PR domain. As the PRDM1- is functionally impaired, with a loss of repressive function on multiple target genes while maintaining normal DNA-binding activity, we hypothesize that the  -isoform, which is overexpressed in NKLLs, may act as a negative regulator of the tumor suppressive α-isoform in NKLLs. In this study, we investigated the possible role of PRDM1- as a negative regulator of tumor suppressor PRDM1-α in NK-cell lymphoma by using a gene silencing technique. Short hairpin-RNA (sh-RNA) construct with sequence targeting to PRDM1- purchasing from biotechnology company was used to knockdown of the gene expression. Series of functional assays were then performed to evaluate the effect of the PRDM1-  knockdown in two NK cell line, YT and NKYS, which xpress endogenous PRDM1-. Comparison was made between the 1) shRNA targeting to nt65-nt94 of PRDM1- sequence, sh-PRDM1 -pGFP-V-RS (shV2), and 2) scrambled-pGFPV-RS (scrambled shRNA), negative control with a non-effective shRNA cassette in pGFP-VRS plasmid. Western blot analysis was performed to examine the efficiency of shRNA in knockdown the expression of PRDM1-  in 293T cells (normal human embryonic kidney cells). The protein expression level for ectopic PRMD1- was reduced in cells expressing shV2 when compared with the negative control. NKYS cell line expressed with shV2 showed a significant reduction in the number of colonies. Percentage of dead cells was found higher in these cells. The proliferation rate of shV2 expressing cells started to retarded significantly on the third day of measurement in the MTS proliferation assay. The cell also underwent G1 cell cycle arrest and had lower proliferation rate, as indicated by cell cycle analysis. For YT cell line expressed with shV2, significant reduction in both colony number and size in methylcellulose colony formation assay was observed. Base on the results obtained from the two NK-cell lines, we suggest that the shV2 inhibit the tumor cell growth. The knockdown of the PRDM1-  lead to an increase level of PRDM1- α. PRDM1- α is a tumor suppressor gene with suppressive function by preventing damaged cells from proliferation or inhibiting the clonogenecity of the tumor cells. An imbalance expression of PRDM1- and PRDM1-αplay an important role in tumor growth and formation, and PRDM1 could possibly be the new tumor suppressor gene in NK-cells lymphoma. / published_or_final_version / Pathology / Master / Master of Medical Sciences

The Best PhD Thesis in the Faculties of Dentistry, Engineering, Medicine and Science (University of Hong Kong), Li Ka Shing Prize,1997-1999 / published_or_final_version / abstract / Pathology / Doctoral / Doctor of Philosophy

Thesis (M.D.)--University of Hong Kong, 2005.

Orientador: Mirela Tinucci Costa / Coorientador: Jose Antonio Sanches / Banca: Silvia Regina Ricci Lucas / Banca: Marcela Marcondes Pinto Rodrigues / Banca: Andrigo Barboza De Nardi / Banca: Sabryna Gouveia Calazans / Resumo: O linfoma cutâneo (LC) em cães é uma doença que se caracteriza pela proliferação clonal de linfócitos atípicos na pele (MILLER et al., 2013). É um linfoma não-Hodgkin, formado por um grupo de doenças neoplásicas malignas de linfócitos T e B e células Natural Killer (NK), cuja primeira manifestação clínica é a presença de lesões cutâneas, sem existir lesão extra cutâneas no momento do diagnóstico (RUEDA; CORTES, 2008). A apresentação clínica é inespecífica e pode mimetizar muitas dermatites (FONTAINE et al., 2010). Nas fases inicias da doença torna-se difícil diferenciar a condição neoplásica de quadro inflamatório linfocítico cutâneo (MURPHY; OLIVRY 2000). Descrita pela primeira vez em 1972 (KELLY et al., 1972), e para muitos autores a doença rara e de etiologia desconhecida (FONTAINE et al., 2009; WITHROW et al., 2013). Diversos estudos mencionaram novas variedades e formas de apresentação do LC na espécie canina baseadas principalmente nos resultados de reações imuno-histoquímicas, comportamento clínico da neoplasia e nas frequentes mudanças da classificação desta doença na espécie humana, que tem levado na classificação em novas variantes de LC (WILLEMZE et al., 2005; DE BOSSCHERE; DECLERCQ, 2008; AFFOLTER et al., 2009; FONTAINE et al., 2009; MILLER et al., 2013; MOORE et al., 2012). Nas últimas três décadas, a classificação morfológica e imunofenotípica do LC em medicina veterinária baseou-se nos critérios de classificação utilizados em humanos (VALLI et al., 2011). O o... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cutaneous lymphoma (LC) in dogs is a disease characterized by the clonal proliferation of atypical lymphocytes in the skin (Miller et al., 2013). It is a non-Hodgkin's lymphoma, consisting of a group of malignant neoplastic diseases of T and B lymphocytes and Natural Killer (NK) cells, whose first clinical manifestation is the presence of cutaneous lesions, with no extra-cutaneous lesion at the time of diagnosis (WHEEL . The clinical presentation is non-specific and may mimic many dermatitis (FONTAINE et al., 2010). In the early stages of the disease, it is difficult to differentiate the neoplastic condition of cutaneous lymphocytic inflammatory disease (MURPHY; OLIVRY 2000). It was first described in 1972 (KELLY et al., 1972), and for many authors, the rare disease of unknown etiology (FONTAINE et al., 2009, WITHROW et al., 2013). Several studies have mentioned new varieties and forms of LC presentation in the canine species based mainly on the results of immunohistochemical reactions, clinical behavior of the neoplasia and the frequent changes in the classification of this disease in the human species, which has led to classification in new variants of LC (Muller et al., 2009), and in the literature on the use of this method (Macker et al., 2009). In the last three decades, the morphological and immunophenotypic classification of CL in veterinary medicine was based on the classification criteria used in humans (VALLI et al., 2011). The objective of this review is to define the current variants, types and subtypes of LC in dogs and establish the main similarities and differences with the existing classification in the human species. / Doutor

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