The glycosaminoglycan hyaluronan is an essential component of the extracellular matrix in all higher organisms, affecting cellular processes such as migration, proliferation and differentiation. Hyaluronan is synthesized by a plasma membrane bound hyaluronan synthase (HAS) which exists in three genetic isoforms. This thesis focuses on the understanding of the hyaluronan biosynthesis by studies on the expression and regulation of the HAS proteins. In order to characterize the structural and functional properties of the HAS isoforms we developed a method to solubilize HAS protein(s) while retaining enzymatic activity. The partially purified HAS protein is, most likely, not asscociated covalently with other components. Cells transfected with cDNAs for HAS1, HAS2 and HAS3 were studied and all three HAS isozymes were able to synthesize high molecular weight hyaluronan chains in intact cells. The regulation of the hyaluronan chain length involves cell specific elements as well as external stimulatory factors. HAS3 transfected cells with high hyaluronan production exhibit reduced migration capacity and reduced amounts of a cell surface hyaluronan receptor molecule (CD44) compared to wild-type cells. The three HAS isoforms were studied and shown to be differentially expressed and regulated in response to external stimuli. Platelet derived growth factor (PDGF-BB) and transforming growth factor (TGF-β1) are important regulators of HAS at both the transcriptional and translational level. The HAS2 isoform is the isoform most susceptible to external regulation. The role of the UDP-glucose dehydrogenase in mammalian glycosaminoglycan biosynthesis was assessed. The enzyme is essential for hyaluronan, heparan sulfate and chondroitin sulfate biosynthesis, but does not exert a rate-limiting effect.

Hyaluronan (HA), a structural component in the extracellular matrix (ECM), has been recognized as a signaling molecule. It is important during various biological activities such as embryogenesis, angiogenesis, wound healing and tumor progression. Increased amount of hyaluronan during embryonic development is necessary for cell migration and differentiation, but the increased production of hyaluronan by tumor cells or tissue fibroblasts is correlated to poor prognosis for tumor progression and chronic inflammation, respectively. Therefore, understanding the mechanisms regulating HA-enriched matrices and the roles of HA in the biological functions is of fundamental biological importance. Four novel findings are described in this thesis: (1) HA fragments (HA12) and the known angiogenic factor FGF-2 promote endothelial cell differentiation by induction of common but also distinct sets of genes, particularly, upregulation of the chemokine CXCL1/GRO1 gene is necessary for HA12-induced angiogenesis and this effect is dependent on CD44 activation. (2) High concentrations of hyaluronan suppress PDGF-BB-induced fibroblasts migration and PDGFRβ tyrosine phosphorylation upon activation of hyaluronan receptor CD44, probably by recruiting a CD44-associated phosphatase to the PDGFRβ. (3) PDGF-BB stimulates HAS2 transcriptional activity and HA synthesis through upregulation of MAP kinase and PI3 kinase signaling pathways in human dermal fibroblasts. (4) Specific suppression of HAS2 gene in the invasive breast cancer cell line Hs578T by RNA interference (RNAi) leads to a less aggressive phenotype of breast tumor cells. This suppressive effect can be reversed by exogenously added hyaluronan. In conclusion, binding of hyaluronan to CD44 plays an important role in cell signaling, inflammation and tumor progression. Further studies are required to elucidate the molecular mechanisms through which hyaluronan levels are regulated under physiological or pathological conditions, and to explore compounds involved in hyaluronan accumulation and activity as targets for therapies of chronic inflammation and tumors.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

Structured abstract Hypothesis Cancer stem cells (CSCs) are subpopulations of cells which could contribute to tumor growth, metastasis formation and chemoresistance. CSCs can be detected by surface markers assessed by immunohistochemistry methods. A typical surface marker for CSCs is CD44 (standard form). We assumed, that CD44(s) could serve as a prognostic factor and marker of chemoresistance in patients with epithelial ovarian cancer. The aim of study 1. To recruit group of patients with histologically verified epithelial ovarian carcinoma. 2. To evaluate prognostic significance of known prognostic factors in our series of patients. 3. To assess the expression of CD44 in specimens of primary tumors and specimens of implantation metastasis using immnunohistochemistry and analyze their correlation. 4. To evaluate the expression of CD44 in relation to known prognostic factors. To analyze the significance of CD44 expression evaluation for overall survival, disease-free interval and chemoresistance. To find CD44 positivity cut-off by using statistical methods Materials and Methods A retrospective study was performed on 87 patients with histologically verified EOC. All patients were tested for primary tumor specimens, 48 of them were tested with regard to both specimens of primary tumor and implantation...

INTRODUÇÃO: o câncer de mama é uma doença heterogênea. Há necessidade de critérios diagnósticos e prognósticos mais refinados. O emprego da imunohistoquímica, através do painel prognóstico, fez despontar a figura do carcinoma triplonegativo e, da mesma forma, a histogenética trouxe à evidência o carcinoma basal. Paralelamente, o conhecimento sobre a origem biológica das neoplasias e da sua heterogeneidade vem sendo acentuadamente debatido através do tema das células-tronco tumorais. OBJETIVOS: investigar a prevalência de carcinomas basais e pentanegativos, numa amostra de carcinomas triplonegativos, e estabelecer associações com a expressão de células-tronco tumorais nestes tumores. Verificar diferenças entre estes subtipos com as variáveis clinicopatológicas. MÉTODOS: 94 carcinomas mamários triplonegativos foram testados para CK5/6, HER1, CD44 e CD24. As expressões desses marcadores por imuno-histoquímica automatizada foram avaliadas através de escore simples de positividade (porcentagem de células) e correlacionadas com os dados clínico-patológicos e análise de sobrevivência. RESULTADOS: carcinomas basais apresentam maior grau tumoral que carcinomas pentanegativos (p=0,004). A negatividade para CD44 (p=0,007) e o perfil CD44- CD24+ (p=0,013) foram associados com maior invasão vascular entre carcinomas triplonegativos. A expressão de CD44 foi associada aos carcinomas basais (p=0,007). O perfil CD44-CD24-/low foi associado aos carcinomas pentanegativos (p=0,04). Nenhuma das variáveis em estudo foi associada com os desfechos clínicos. CONCLUSÃO: Carcinomas mamários basais e pentanegativos são subtipos tumorais bastante próximos. Nosso estudo é o primeiro desenhado especificamente para avaliar a presença células tronco-tumorais mamárias entre carcinomas basais e pentanegativos, onde o perfil CD44-CD24-/low foi associado ao subtipo pentanegativo, e o perfil CD44-CD24+ à invasão vascular, resultados que merecem confirmação por histogenética em estudos de maior porte. / INTRODUCTION: Breast cancer is a heterogeneous disease, and there is a need for more refined diagnostic and prognostic criteria. Immunohistochemistry, as a breast prognostic panel, has given rise to triple-negative carcinoma, as well as histogenetics highlighted basal carcinoma. Concomitantly, the understanding of the biological origins of neoplasia and its heterogeneity has been strongly debated through the theme of cancer stem cells. OBJECTIVES: To investigate the prevalence of basal and penta-negative carcinomas in a sample of triple-negative carcinomas and to establish associations with cancer stem cells (CD44/CD24 expression profiles) and the clinicopathological variables within these tumors. METHODS: Ninety-four triplenegative breast carcinomas were tested for CK5/6, HER1, CD44 and CD24. The expression of these markers was evaluated by automated immunohistochemistry using a simple positivity score (percentage of cells) and was correlated with the clinicopathological and survival analysis data. RESULTS: Basal carcinomas had higher tumor grades than penta-negative carcinomas (p=0.004). CD44 negativity (p=0.007) and the CD44-CD24+ phenotype (p=0.013) were associated with increased vascular invasion amongst the triple-negative carcinomas. CD44 expression was associated with basal carcinomas (p=0.007). The CD44-CD24-/low phenotype was associated with penta-negative carcinomas. None of the variables in the study were associated with clinical outcome. CONCLUSION: Basal and penta-negative breast carcinomas are closely related tumor subtypes. Our study is the first to be specifically designed to assess the presence of breast cancer stem cells in basal and pentanegative carcinomas. The CD44-CD24-/low phenotype was associated with the pentanegative subtype, and the CD44-CD24+ phenotype was associated with vascular invasion. These results require histogenetic confirmation in larger studies.

Dissertação (mestrado) - Pontifícia Universidade Católica do Paraná, Curitiba, 2011 / Bibliografia: f. 58-67 / Introdução: O câncer de mama é o tumor mais comum entre as mulheres, com exceção dos tumores de pele não melanoma, e uma doença muito heterogênea. Na última década foram identificados basicamente 5 subtipos moleculares intrínsecos: Luminal A, Luminal B, H / Introduction: Breast cancer is the most frequent tumor in women, except skin tumors non melanoma, and is a very heterogeneous disease. In the last decade there were identified basically 5 intrinsic molecular subtypes: Luminal A, Luminal B, HER2, Basal, Cl

HIRTH, C.G. Valor prognóstico de marcadores de diferenciação neuroendócrina e de células-tronco em pacientes submetidos a prostatectomia radical por câncer de próstata localizado. 2016. 134 f. Dissertação (Mestrado em Patologia) - Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Erika Fernandes (erikaleitefernandes@gmail.com) on 2017-01-18T13:27:42Z No. of bitstreams: 1 2016_dis_cghirth.pdf: 3230766 bytes, checksum: 651e7c54b6b9dec6b84cbf5bcfd553cd (MD5) / Approved for entry into archive by Erika Fernandes (erikaleitefernandes@gmail.com) on 2017-01-18T13:27:53Z (GMT) No. of bitstreams: 1 2016_dis_cghirth.pdf: 3230766 bytes, checksum: 651e7c54b6b9dec6b84cbf5bcfd553cd (MD5) / Made available in DSpace on 2017-01-18T13:27:53Z (GMT). No. of bitstreams: 1 2016_dis_cghirth.pdf: 3230766 bytes, checksum: 651e7c54b6b9dec6b84cbf5bcfd553cd (MD5) Previous issue date: 2016-11-17 / This study aimed to evaluate the new immunohistochemical markers related to neuroendocrine differentiation induction and stem cells with prognostic factors and biochemical recurrence in patients submitted to radical prostatectomy. Therefore, patients operated at the Hospital Walter Cantídio, Federal University of Ceará, in the period of 2008-2013, underwent clinical and outpatient follow-up, between the years 2008-2016. Biochemical recurrence was evaluated and was correlated with pathological characteristics and immunohistochemical reactions. Chromogranin (neuroendocrine differentiation), Aurora Kinase A (AURKA), N-MYC, C-MYC and CD44s were performad in paraffined material. From 74 patients underwent surgery was obtained the followup of 69, in a median period of 41 (2-89) months. Neoplastic neuroendocrine differentiation was associated with seminal vesicles infiltration (p = 0.032) and stage (p = 0.030). C-MYC was associated with Gleason score (p = 0.001) and seminal vesicles infiltration (p = 0.014). AURKA was expressed in rare cases. N-MYC protein was negative in all patients. CD44s was associated with lower preoperative PSA levels and lower Gleason scores. Biochemical recurrence was observed in 27.0% of patients. Recurrence was associated with serum preoperative PSA, Gleason score, seminal vesicle invasion and staging at least in one form of analysis. There was no significant association between recurrence and neuroendocrine differentiation, C-MYC and CD44s expression. Therefore, immunohistochemical detection of neuroendocrine differentiation, expression of C-MYC and loss of CD44s were related to more aggressive carcinomas (PSA, Gleason, seminal vesical invasion and/or stage), but no association with biochemical recurrence. Classic prognostic factors were affirmed like biochemical recurrence predictores. / Este estudo objetivou avaliar novos marcadores imuno-histoquímicos relacionados à indução da diferenciação neuroendócrina e células-tronco com fatores de prognóstico e recorrência bioquímica, em pacientes submetidos à prostatectomia radical. Para tanto, pacientes operados no Hospital Walter Cantídio, Universidade Federal do Ceará, no período de 2008 a 2013, foram submetidos a acompanhamento clínico-ambulatorial, entre os anos de 2008 a 2016. Avaliou-se a proporção daqueles que apresentaram recorrência bioquímica, bem como as características clínico-patológicas e a marcação em reações de imuno-histoquímica para cromogranina (diferenciação neuroendócrina), Aurora quinase A (AURKA), N-MYC, C-MYC e CD44s, em material parafinado. De 74 pacientes submetidos à cirurgia, obteve-se acompanhamento de 69, com tempo de seguimento de 41 (2-89) meses; diferenciação neuroendócrina na neoplasia se associou com infiltração de vesículas seminais (p=0,032) e estadiamento (p=0,030). C-MYC associou-se com escore de Gleason (p=0,001) e infiltração de vesículas seminais (p=0,014). AURKA expressou-se em raros casos. N-MYC foi negativo em todos os pacientes. CD44s se associou com menores níveis de PSA pré-operatório e menores escores de Gleason. Observou-se recorrência bioquímica em 27,0% dos pacientes. Recorrência se associou, em pelo menos uma das formas de análise, com níveis séricos de PSA pré-operatório, escore de Gleason, invasão de vesículas seminais e estadiamento. Não houve associação significativa entre recorrência e diferenciação neuroendócrina, C-MYC e CD44s. Dessa forma, nesse estudo, a detecção imuno-histoquímica da diferenciação neuroendócrina; a expressão de C-MYC e a perda da expressão de CD44s relacionaram-se com carcinomas mais agressivos (PSA, Gleason, infiltração de vesícula seminal e/ou estadiamento), porém sem associação com a recorrência bioquímica; bem como confirma a importância de fatores prognósticos considerados como clássicos em série regional de pacientes com câncer de próstata.

Made available in DSpace on 2014-06-11T19:23:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-23Bitstream added on 2014-06-13T19:29:09Z : No. of bitstreams: 1 gouveia_gm_me_araca.pdf: 550439 bytes, checksum: 076629ee6a296748de89f110784f058d (MD5) / Os tumores mamários são as mais freqüentes neoplasias em cadelas, representando cerca de 50% dos tumores diagnosticadas nesta espécie e tem maior incidência em fêmeas de meia idade a idosas. Têm sido utilizadas como modelo de estudo para neoplasias mamárias de mulher devido às várias características comuns como as similaridades histológicas e imuno- histoquímicas. Na última década, estudos baseados nos perfis moleculares das neoplasias mamárias, tornaram possível a identificação de algumas células neoplásicas com características de células tronco – as células tronco tumorais (CTT). Uma das moléculas putativas para marcação das CTTs é o CD44. A telomerase, que vem sendo relatada como marcador tumoral, é potencialmente expressa também em CTTs. Estudos recentes estabeleceram um elo crucial entre a transição epitelial-mesenquimal (EMT) e a aquisição de propriedades moleculares e funcionais de células-tronco. Por este motivo analisamos a expressão das proteínas CD44, Citoqueratinas AE1/AE3 e Vimentina, e da enzima telomerase, em tumores mamários de cadelas a fim de investigar o potencial de marcação de CTTs e sua relação com a EMT. Para tal foram utilizados métodos de imuno-histoquímica em tecidos parafinizados tanto in vivo quanto in vitro, fazendo-se uso de técnicas como Tissue MicroArrays (TMA), citoinclusão de tecidos tumorais e cultivos celulares. A expressão da telomerase nas células de tumores mamários cultivadas foi analizada por PCR em tempo real. Nas amostras de tecido parafinizado in vivo, a imunomarcação da citoqueratina demonstrou diferença significativa entre tumores benignos e malignos (p˂0,05), mostrando-se mais intensa em tumores malignos. Já a vimentina apresentou maior intensidade de marcação em tumores benignos, porém não apresentando diferença significativa (p˂0,05)... / Mammary tumors are the most frequent cancers in dogs, representing about 50% of tumors, and have a higher incidence in females of middle aged and elderly. These tumors have been used as a model for breast cancer in women due to several common characteristics such as histological and immunohistochemical similarities. In the last decade, studies based on molecular profiles of breast cancer, made possible the identification of some neoplastic cells with characteristics of stem cells – cancer stem cells (CSC). One of the putative molecules of CSCs is CD44. Telomerase, which has been reported as a tumor marker, is potentially also expressed in CSCs. Recent studies have established a crucial link between the epithelial- mesenchymal transition (EMT) and the acquisition of molecular and functional properties of stem cells. For that reason we analyzed the expression of proteins CD44, Cytokeratins AE1/AE3 and Vimentin, and the telomerase enzyme, in dogs mammary tumors, to investigate the potencial for CSC markers, and its relation with the EMT using immunohistochemistry in paraffin embedded tissues in both in vivo and in vitro, making use of techniques such as Tissue MicroArrays (TMA), cell blocks from tumors and cell cultures. Besides that, we analyzed the telomerase expression in mammary tumor cultivated cells by quantitative real time PCR. Immunostaining of cytokeratin had no significant difference between benign and malignant tumors (p ˂ 0,05), being more intense in malignant tumors. However vimentina showed higher staining intensity in benign tumors, but with no significant difference (p ˂ 0,05). The expression of CD44 was higher in malignant tumors that have greater proliferative and metastatic potencial, however its relation with EMT was not detected in the analyzed tumors. Telomerase expression was positive in the neoplastic cultivated cells, however without significant difference... (Complete abstract click electronic access below)

INTRODUÇÃO: o câncer de mama é uma doença heterogênea. Há necessidade de critérios diagnósticos e prognósticos mais refinados. O emprego da imunohistoquímica, através do painel prognóstico, fez despontar a figura do carcinoma triplonegativo e, da mesma forma, a histogenética trouxe à evidência o carcinoma basal. Paralelamente, o conhecimento sobre a origem biológica das neoplasias e da sua heterogeneidade vem sendo acentuadamente debatido através do tema das células-tronco tumorais. OBJETIVOS: investigar a prevalência de carcinomas basais e pentanegativos, numa amostra de carcinomas triplonegativos, e estabelecer associações com a expressão de células-tronco tumorais nestes tumores. Verificar diferenças entre estes subtipos com as variáveis clinicopatológicas. MÉTODOS: 94 carcinomas mamários triplonegativos foram testados para CK5/6, HER1, CD44 e CD24. As expressões desses marcadores por imuno-histoquímica automatizada foram avaliadas através de escore simples de positividade (porcentagem de células) e correlacionadas com os dados clínico-patológicos e análise de sobrevivência. RESULTADOS: carcinomas basais apresentam maior grau tumoral que carcinomas pentanegativos (p=0,004). A negatividade para CD44 (p=0,007) e o perfil CD44- CD24+ (p=0,013) foram associados com maior invasão vascular entre carcinomas triplonegativos. A expressão de CD44 foi associada aos carcinomas basais (p=0,007). O perfil CD44-CD24-/low foi associado aos carcinomas pentanegativos (p=0,04). Nenhuma das variáveis em estudo foi associada com os desfechos clínicos. CONCLUSÃO: Carcinomas mamários basais e pentanegativos são subtipos tumorais bastante próximos. Nosso estudo é o primeiro desenhado especificamente para avaliar a presença células tronco-tumorais mamárias entre carcinomas basais e pentanegativos, onde o perfil CD44-CD24-/low foi associado ao subtipo pentanegativo, e o perfil CD44-CD24+ à invasão vascular, resultados que merecem confirmação por histogenética em estudos de maior porte. / INTRODUCTION: Breast cancer is a heterogeneous disease, and there is a need for more refined diagnostic and prognostic criteria. Immunohistochemistry, as a breast prognostic panel, has given rise to triple-negative carcinoma, as well as histogenetics highlighted basal carcinoma. Concomitantly, the understanding of the biological origins of neoplasia and its heterogeneity has been strongly debated through the theme of cancer stem cells. OBJECTIVES: To investigate the prevalence of basal and penta-negative carcinomas in a sample of triple-negative carcinomas and to establish associations with cancer stem cells (CD44/CD24 expression profiles) and the clinicopathological variables within these tumors. METHODS: Ninety-four triplenegative breast carcinomas were tested for CK5/6, HER1, CD44 and CD24. The expression of these markers was evaluated by automated immunohistochemistry using a simple positivity score (percentage of cells) and was correlated with the clinicopathological and survival analysis data. RESULTS: Basal carcinomas had higher tumor grades than penta-negative carcinomas (p=0.004). CD44 negativity (p=0.007) and the CD44-CD24+ phenotype (p=0.013) were associated with increased vascular invasion amongst the triple-negative carcinomas. CD44 expression was associated with basal carcinomas (p=0.007). The CD44-CD24-/low phenotype was associated with penta-negative carcinomas. None of the variables in the study were associated with clinical outcome. CONCLUSION: Basal and penta-negative breast carcinomas are closely related tumor subtypes. Our study is the first to be specifically designed to assess the presence of breast cancer stem cells in basal and pentanegative carcinomas. The CD44-CD24-/low phenotype was associated with the pentanegative subtype, and the CD44-CD24+ phenotype was associated with vascular invasion. These results require histogenetic confirmation in larger studies.

IntroduÃÃo â AlteraÃÃes na expressÃo ou funÃÃo das molÃculas de adesÃo (MA) nas cÃlulas leucÃmicas podem contribuir para a evoluÃÃo e no comportamento biolÃgico das leucemias agudas. A expressÃo aumentada nas LLAs parece relacionar-se aos mecanismos de disseminaÃÃo extramedular dos linfoblastos, infiltraÃÃo do SNC e formaÃÃo de massas tumorais. Objetivos â Analisar a expressÃo da L-selectina e do CD44 nas LLAs em crianÃas e adolescentes. Avaliar os fatores prognÃsticos (idade, sexo, leucometria ao diagnÃstico, imunofenÃtipo, classificaÃÃo FAB, EGIL, Ãndice de DNA e resposta ao tratamento de induÃÃo) e as apresentaÃÃes extramedulares das LLAs e correlacionÃ-los com essas MA. Pacientes e MÃtodos â Foram avaliados 76 pacientes com LLA, tratados com o Protocolo GBTLI-LLA. O diagnÃstico foi baseado em critÃrios FAB, imunofenotÃpicos (EGIL) e citogenÃticos. A expressÃo das MA foi avaliada por citometria de fluxo, utilizando tripla marcaÃÃo. O anticorpo monoclonal CD45-PerCP (ImmunotechÂ) foi utlizado como marcador dos linfoblastos. O CD44-PE (Clone HP2/9 - ImmunostepÂ) e o CD62L-FITC (Clone HI62L - ImmunostepÂ) foram utilizados para a marcaÃÃo das MA. Para a anÃlise das amostras e o cÃlculo da intensidade mÃdia de fluorescÃncia foi utilizado o programa Cell Quest. Na anÃlise estatÃstica utilizou-se o software SPSS 16.0. A associaÃÃo entre as variÃveis, os fatores prognÃsticos e resposta foi realizada com os testes de Qui-quadrado, exato de Fisher e Mann-Whitney. Sobrevida global foi determinada por curvas Kaplan-Meier e teste log-rank. AnÃlise multivariada por modelo proporcional de Cox foi utilizada para assegurar a independÃncia dos fatores prognÃsticos. Resultados â A mÃdia de idade foi 6,3Â0,5 anos (5m -17a) e predominou o sexo masculino (65%). Ao diagnÃstico os achados clÃnicos foram: hepatomegalia (63%), esplenomegalia (58%) e linfadenomegalia (44%). A infiltraÃÃo SNC ocorreu em 6,6% dos casos e o alargamento de mediastino em 11,8%. Quanto ao risco, 54% eram baixo risco e 46% alto risco. A classificaÃÃo FAB determinou 83% como L1 e 17% L2. DiagnÃstico de LLA-B foi mais frequente (89,5%) e o da LLA-T em 10,5% dos pacientes. O subtipo EGIL mais prevalente foi B II e B III, 51,5% e 45% respectivamente. O IDNA &#8805; 1.16 foi encontrado em 19% dos pacientes e associou-se a bom prognÃstico. Na avaliaÃÃo do D8, 95% dos pacientes apresentaram contagem de blastos <1000/mm3 e leucÃcitos < 5.000/mm3. A taxa de remissÃo de induÃÃo foi de 95% e ocorreram 2,6% de Ãbitos na induÃÃo. Observou-se uma maior expressÃo do CD44 na LLA-T (87,5%/ IMF=150,44Â20,29), porÃm sem significÃncia estatÃstica. LLAs com massa tumoral apresentaram 84% de expressÃo do CD44, quando comparada a 52% das LLAs sem massa tumoral (p=0.01; OR=4,8). ExpressÃo aumentada da L-selectina na LLA-T (87,5%/IMF=272,33Â52,72) foi estatisticamente significante (p=0,004), comparado a LLA-B (54,5%/ IMF= 115,90Â12,75). NÃo houve correlaÃÃo entre os outros fatores prognÃsticos e essas MA. Na anÃlise multivariada as variÃveis de maior impacto para a sobrevida foram: a leucometria ao diagnÃstico, sexo, imunofenÃtipo T e a L-selectina. ConclusÃo â A expressÃo da L-selectina e do CD44 estÃo aumentadas nas LLAs estudadas, principalmente na LLA-T. O CD44 correlacionou-se com LLAs com massas tumorais e parece estar relacionado aos mecanismos de disseminaÃÃo extramedular dos linfoblastos / Introduction â Altered expression or function of adhesion molecules on leukemic blasts may contribute to the evolution of acute leukemia and its biological behavior. The elevated expression of adhesion molecules in ALL might be correlated with the extramedullary dissemination of blast cells, CNS involvement and leukemia tumor burden. Purpose â To analyze the expression of L-selectin and CD44 in ALL in children and adolescents. As well as to evaluate the prognostic factors (age, gender, initial leukocyte count, immunophenotype, FAB and EGIL classification, DNA index and early response to treatment) and the extramedullary presentation of ALL, to finally correlate the prognostic factors with these adhesion molecules. Patients and Methods â From November 2007 to November 2008, 76 patients with newly diagnosed ALL started on Brazilian GBTLI-ALL Protocol. The diagnosis was based on cytological, immunophenotypic, and cytogenetic methods. The mean fluorescence intensity (MFI) and the percentage of the adhesion molecules blasts cells was measured by flow cytometry using triple staining with McAb directly conjugated. CD45-PerCP positive cells were gated for blasts analysis. Anti-CD44-PE (Clone HP2/9 - ImmunostepÂ) and CD62L-FITC (Clone HI62L - ImmunostepÂ) were used to mark the adhesion molecules. The Cell Quest program was used for data acquisition and analysis. Statistical analysis was done by SPSS 16.0 Software. The association of features, prognosis and response to treatment was assessed by Chi-square, Fisher exact and Mann-Whitney tests. Overall survival curves were constructed by the Kaplan-Meier method and the log-rank test. Multivariate Cox regression analysis showed independent prognostic factors. Results â The mean age at diagnosis was 6.3Â0.5 years (range 9mo to 17yr) and 65% of them were boys. Clinical findings were hepatomegaly (63%), splenomegaly (58%), lymphadenopathy (44%). CNS involvement was detected in 6.6% of cases and mediastinal mass appeared in 11.8% of them. Patients were classified into low risk (54%) and high risk (46%). FAB classification identified 83% as L1 and 17% as L2. Immunophenotypically, 89.5% of patients were classified as B-lineage ALL and 10.5% as T-lineage ALL. The most frequent EGIL subtype was B common and pre-B-ALL (51.5% and 45.5%, respectively). DNA index greater than 1.16 was found in 19% of the patients and was associated with favorable prognosis. On the D8 evaluation, 95% of the patients had blast count lower than 1.000/mm3 and leukocyte count lower than 5.000/mm3. The remission induction rate was 95% and there was a rate of 2.6% of death during induction therapy. CD44 had greater expression to the rate of 87.5% in T-cell ALL (MFI=150.44Â20.29) with no statistical correlation. A significant positive correlation was demonstrated between 84% of CD44 expression and Leukemia burden tumor cases (p=0.01; OR=4.8). There was statistical correlation between L-selectin expression (87.5%/MFI=272.33Â52.72) and T-cell ALL (p=0,004). No significant correlation was detected between L-selectin and CD44 expression and other prognostic factors. Multivariate statistical analysis (adjusted for overall survival) indicated that initial leukocyte count, gender, T immunophenotype and L-selectin were independent factors. Conclusion â L-selectin and CD44 expressions were elevated in ALL studied, mainly in T-cell ALL. The research demonstrated that there is an association between CD44 expression and leukemia tumor burden, which might be involved in the dissemination of leukemic cells and the progression of the disease.