RESUMO
Oral transmission of Chagas disease has been increasing in Latin American countries. The present study aimed to investigate changes in hepatic function, coagulation factor levels and parasite load in human acute Chagas disease (ACD) secondary to oral Trypanosoma cruzi transmission. Clinical and epidemiological findings of 102 infected individuals attended in the State of Pará from October 2013 to February 2016 were included. The most common symptoms were fever (98%), asthenia (83.3%), face and limb edema (80.4%), headache (74.5%) and myalgia (72.5%). The hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of 30 ACD patients were higher compared with controls, and this increase was independent of the treatment with benznidazole. Moreover, ACD individuals had higher plasma levels of activated protein C and lower levels of factor VII of the coagulation cascade. Patients with the highest parasite load had also the most increased transaminase levels. Also, ALT and AST were associated moderately (r = 0.429) and strongly (r = 0.595) with parasite load respectively. In conclusion, the present study raises the possibility that a disturbance in coagulation and hepatic function may be linked to human ACD.
Assuntos
Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Doença de Chagas/fisiopatologia , Fator VIIa/análise , Fígado/fisiopatologia , Proteína C/análise , Doença Aguda , Adulto , Biomarcadores/sangue , Brasil/epidemiologia , Estudos de Casos e Controles , Doença de Chagas/sangue , Doença de Chagas/enzimologia , Doença de Chagas/transmissão , Feminino , Humanos , Fígado/enzimologia , Masculino , Pessoa de Meia-Idade , Carga Parasitária , Estudos ProspectivosRESUMO
Oral transmission of Chagas disease has been increasing in Latin American countries. The present study aimed to investigate changes in hepatic function, coagulation factor levels and parasite load in human acute Chagas disease (ACD) secondary to oral Trypanosoma cruzi transmission. Clinical and epidemiological findings of 102 infected individuals attended in the State of Pará from October 2013 to February 2016 were included. The most common symptoms were fever (98%), asthenia (83.3%), face and limb edema (80.4%), headache (74.5%) and myalgia (72.5%). The hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of 30 ACD patients were higher compared with controls, and this increase was independent of the treatment with benznidazole. Moreover, ACD individuals had higher plasma levels of activated protein C and lower levels of factor VII of the coagulation cascade. Patients with the highest parasite load had also the most increased transaminase levels. Also, ALT and AST were associated moderately (r = 0.429) and strongly (r = 0.595) with parasite load respectively. In conclusion, the present study raises the possibility that a disturbance in coagulation and hepatic function may be linked to human ACD.
Assuntos
Animais , Masculino , Feminino , Adulto , Aspartato Aminotransferases/sangue , Proteína C/análise , Fator VIIa/análise , Doença de Chagas/fisiopatologia , Alanina Transaminase/sangue , Fígado/fisiopatologia , Brasil/epidemiologia , Biomarcadores/sangue , Estudos de Casos e Controles , Doença Aguda , Estudos Prospectivos , Doença de Chagas/enzimologia , Doença de Chagas/sangue , Doença de Chagas/transmissão , Carga Parasitária , Fígado/enzimologia , Pessoa de Meia-IdadeRESUMO
Thrombosis is a common phenomenon in patients with malignancies. It is believed that thrombosis is multifactorial and that in addition to mechanisms directly associated with cancer and its treatment, it may also be related to the interaction between the immune system and clotting. The present work describes four cancer patients (three adults and one child) whose clinical course was characteristic of catastrophic antiphospholipid syndrome (CAPS) in intensive care units of the National Cancer Institute of Rio de Janeiro. The presence of findings similar to those in CAPS can be attributed to an unbalanced interaction between the immune system and coagulation.
Assuntos
Síndrome Antifosfolipídica , Neoplasias dos Ductos Biliares , Neoplasias Ósseas , Colangiocarcinoma , Neoplasias do Colo , Fíbula/patologia , Neoplasias Pulmonares , Sarcoma de Ewing , Trombose , Idoso , Anticorpos Antifosfolipídeos/sangue , Anticoagulantes/uso terapêutico , Síndrome Antifosfolipídica/etiologia , Síndrome Antifosfolipídica/imunologia , Síndrome Antifosfolipídica/terapia , Autoimunidade , Neoplasias dos Ductos Biliares/complicações , Neoplasias dos Ductos Biliares/imunologia , Neoplasias dos Ductos Biliares/patologia , Coagulação Sanguínea/imunologia , Neoplasias Ósseas/complicações , Neoplasias Ósseas/imunologia , Neoplasias Ósseas/patologia , Criança , Colangiocarcinoma/complicações , Colangiocarcinoma/imunologia , Colangiocarcinoma/patologia , Neoplasias do Colo/complicações , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Feminino , Glucocorticoides/uso terapêutico , Humanos , Neoplasias Pulmonares/complicações , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Plasmaferese/métodos , Sarcoma de Ewing/complicações , Sarcoma de Ewing/imunologia , Sarcoma de Ewing/patologia , Índice de Gravidade de Doença , Trombose/etiologia , Trombose/imunologia , Trombose/terapia , Resultado do TratamentoRESUMO
PURPOSE: The purpose of this study is to evaluate the prevalence and the prognostic impact of antiphospholipid antibodies (aPL) in critically ill cancer patients. METHODS: This is a prospective cohort study in adult patients admitted to the intensive care unit for more than 48 hours at a cancer center. Clinical and laboratory data including coagulation parameters were obtained. Cox proportional hazard models were used to identify predictors of 6-month mortality. RESULTS: Ninety-five (solid tumor, 79%; hematologic malignancies, 21%) patients were included, and aPL were identified in 74% of them. Median Simplified Acute Physiology Score 3 and Sequential Organ Failure Assessment scores were 51 (37-65) and 5 (2-8) points, respectively. The most frequent aPL were lupus anticoagulant (61%) and anti-ß2 glicoprotein I (32%). Vascular complications occurred in 18% of patients and were comparable between aPL+ and aPL- patients. Sepsis and need for renal replacement therapy were more frequent in aPL+ patients. Hospital and 6-month mortality rates were 44% and 56%, respectively. Higher Sequential Organ Failure Assessment scores (each point) (hazard ratios [HR]=2.83 [95% confidence interval, 1.59-5.00]), medical admissions (HR=2.66 [1.34-5.27]), and d-dimer more than 500 ng/dL (HR=1.89 (1.04-3.44]) were independently associated with mortality. After adjusting for these covariates, aPL status was not associated with outcomes (HR=1.22 [0.60-2.47]). CONCLUSIONS: Lupus anticoagulants were frequent in critically ill cancer patients. However, they were not associated with medium-term survival in these patients.
Assuntos
Anticorpos Antifosfolipídeos/sangue , Neoplasias/imunologia , Idoso , Intervalos de Confiança , Estado Terminal , Feminino , Produtos de Degradação da Fibrina e do Fibrinogênio/análise , Neoplasias Hematológicas/imunologia , Neoplasias Hematológicas/mortalidade , Humanos , Unidades de Terapia Intensiva , Inibidor de Coagulação do Lúpus/sangue , Masculino , Pessoa de Meia-Idade , Neoplasias/mortalidade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Terapia de Substituição Renal , Sepse/sangue , beta 2-Glicoproteína I/sangueRESUMO
Given the lack of information about catastrophic antiphospholipid syndrome (APS) in pediatric patients, the objective of the current study was to describe the clinical characteristics, laboratory features, treatment, and outcome of pediatric patients with catastrophic APS and compare them with the adult patients with catastrophic APS. We identified patients who were under 18years of age at time of catastrophic APS diagnosis included in the international registry of patients with catastrophic APS (CAPS Registry). Their main demographic and clinical characteristics, laboratory features, treatment, and outcome were described and compared with those of adult patients with catastrophic APS. From the 446 patients included in the CAPS Registry as of May 2013, 45 (10.3%) patients developed 46 catastrophic events before 18years of age (one patient presented two episodes). Overall, 32 (71.1%) patients were female and the mean age was 11.5±4.6years (range, 3months-18years). A total of 31 (68.9%) patients suffered from primary APS and 13 (28.9%) from systemic lupus erythematosus (SLE). The main differences between the two groups of patients were the higher prevalence of infections as precipitating factor for catastrophic event in the pediatric population (60.9% versus 26.8% in the adult population, p<0.001) and of peripheral vessel thrombosis (52.2% versus 34.3%, p=0.017). In addition, catastrophic APS was the first manifestation of APS more frequently in pediatric patients (86.6% versus 45.2%, p<0.001). Interestingly, pediatric patients showed a trend of lower mortality, although the difference was not statistically significant (26.1% versus 40.2%; odds ratio, 1.9; 95% confidence interval, 0.96-3.79; p=0.063). No differences were found neither in the laboratory features nor in the isolated or combination treatments between groups. Catastrophic APS in pediatric patients is a rare disease. There are minimal differences in the clinical and laboratory features, treatment, and outcome of pediatric and adult catastrophic APS patients.
Assuntos
Síndrome Antifosfolipídica/fisiopatologia , Sistema de Registros , Adolescente , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/patologia , Síndrome Antifosfolipídica/terapia , Criança , Pré-Escolar , Feminino , Humanos , Lúpus Eritematoso Sistêmico/diagnóstico , Lúpus Eritematoso Sistêmico/patologia , Lúpus Eritematoso Sistêmico/fisiopatologia , Masculino , Doenças Raras/diagnóstico , Doenças Raras/patologia , Doenças Raras/fisiopatologia , Doenças Raras/terapiaRESUMO
Thrombosis is highly prevalent in cancer patients, being accepted as a bad prognosis marker. The importance of various mechanisms involved in the thrombophilic state of lung cancer patients is not well understood. In this prospective study, involving 109 unselected patients with lung adenocarcinoma, thrombosis was present in 24% of patients and affected survival in a bivariable model. However, in a multivariable evaluation, considering all the factors under study, only LAC and IgM anti-beta(2) GP I modified thrombosis risk, whereas in a Kaplan-Meyer regression model, thrombosis, IL-6, LAC, factor VIII, and IgM anti-beta(2) GP I interfered with patient's survival.
Assuntos
Adenocarcinoma/complicações , Autoanticorpos/sangue , Coagulação Sanguínea , Citocinas/sangue , Neoplasias Pulmonares/complicações , Trombose Venosa/etiologia , Adenocarcinoma/sangue , Adenocarcinoma/imunologia , Adenocarcinoma/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Trombose Venosa/sangue , Trombose Venosa/imunologia , Trombose Venosa/mortalidadeRESUMO
Thrombosis is a frequent finding in cancer patients, being referred to as a poor prognostic factor. The mechanisms underlying the thrombophilic state in malignancy are not well elucidated but involve a complex interaction between tumor and host cells as well as the hemostatic system. A number of studies have demonstrated the presence of antiphospholipid antibodies (aPL) in cancer patients, suggesting a potential role in tumor-associated thrombosis. A prospective analysis has been performed in a group of lung adenocarcinoma patients in respect to the presence of aPL and thrombotic manifestations. Lupus anticoagulant (LAC) was identified in 61 out of 105 patients and it correlated highly with thrombosis (22/61, LAC positive vs 2/44, LAC negative RR=7.93; p<0.001). On the other hand, patients that displayed IgM anti-beta2-glycoprotein I (abeta2GPI) (22/80) showed an unexpected decrease in thrombosis risk (2/22, with IgM abeta2GPI vs 18/58, without IgM abeta2GPI RR=0.29; p=0.04). Considerations on the mechanisms that link cancer, thrombosis and aPL are discussed in this article.
Assuntos
Adenocarcinoma/diagnóstico , Adenocarcinoma/imunologia , Anticorpos Antifosfolipídeos/sangue , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/imunologia , Adenocarcinoma/sangue , Adenocarcinoma/mortalidade , Anticorpos Antifosfolipídeos/imunologia , Autoanticorpos/sangue , Coagulação Sanguínea , Humanos , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/mortalidade , Inibidor de Coagulação do Lúpus/imunologia , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Fatores de Risco , Análise de Sobrevida , Trombose , beta 2-Glicoproteína I/imunologiaRESUMO
OBJECTIVES: To describe the clinical outcomes and thrombotic events in a series of critically ill cancer patients positive for antiphospholipid (aPL) antibodies. DESIGN: Retrospective case series study. SETTING: Medical-surgical oncologic intensive care unit (ICU). PATIENTS AND PARTICIPANTS: Eighteen patients with SIRS/sepsis and multiple organ failure (MOF) and positive for aPL antibodies, included over a 10-month period. INTERVENTIONS: None MEASUREMENTS AND RESULTS: aPL antibodies and coagulation parameters were measured up to 48 hours after the occurrence of acrocyanosis or arterial/venous thrombotic events. When current criteria for the diagnosis of aPL syndrome were applied, 16 patients met the criteria for 'probable' and two patients had a definite diagnosis of APL syndrome in its catastrophic form (CAPS). Acrocyanosis, arterial events and venous thrombosis were present in eighteen, nine and five patients, respectively. Sepsis, cancer and major surgery were the main precipitating factors. All patients developed MOF during the ICU stay, with a hospital mortality rate of 72% (13/18). Five patients were discharged from the hospital. There were three survivors at 90 days of follow-up. New measurements of lupus anticoagulant (LAC) antibodies were performed in these three survivors and one patient still tested positive for these antibodies. CONCLUSIONS: In this small series of patients, we observed a high frequency of auto-antibodies and micro- and macro-vascular thrombotic events in critically ill cancer patients. The coexistence of sepsis or SIRS and aPL antibodies was often associated with MOF and death. More studies are necessary to determine the pathophysiological significance of antiphospholipid antibodies in severely ill cancer patients.
Assuntos
Anticorpos Antifosfolipídeos/sangue , Estado Terminal , Neoplasias Gastrointestinais/complicações , Linfoma não Hodgkin/complicações , Insuficiência de Múltiplos Órgãos/etiologia , Sepse/complicações , Idoso , Anticorpos Antifosfolipídeos/imunologia , Síndrome Antifosfolipídica/diagnóstico , Síndrome Antifosfolipídica/imunologia , Feminino , Neoplasias Gastrointestinais/imunologia , Humanos , Neoplasias Laríngeas/complicações , Neoplasias Laríngeas/imunologia , Linfoma não Hodgkin/imunologia , Masculino , Pessoa de Meia-Idade , Insuficiência de Múltiplos Órgãos/imunologia , Estudos Retrospectivos , Sepse/imunologia , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Trombose/complicações , Trombose/imunologiaRESUMO
There is a high incidence of thrombosis in cancer patients. Retrospective studies indicate that lupus anticoagulant (LA) antibodies can be a thrombosis risk factor in cancer. In 77 patients with different forms of cancer LA and thrombosis incidence were retrospectively evaluated. In a prospective study, with 42 lung adenocarcinoma patients, we measured plasma LA, fibrinogen, factor VIII (FVIII), and thrombosis incidence. A high frequency of LA and thrombosis were observed in both studies. In isolation LA, increased levels of FVIII and fibrinogen could not be considered good markers for the development of thrombosis.
Assuntos
Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Inibidor de Coagulação do Lúpus/metabolismo , Trombose/metabolismo , Trombose/patologia , Humanos , Fatores de RiscoRESUMO
Reduced-intensity conditioning has extended the use of allogeneic hematopoietic stem cell transplantation (HSCT) to patients otherwise not eligible for this treatment due to older age or frailty. One hundred twelve acute myelogenous leukemia/myelodysplastic syndromes patients received fludarabine and melphalan (FM) conditioning with allogeneic HSCT. Most patients (73%) were not in remission. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and mini-methotrexate. Median age was 55 years (range, 22-74). Donors were related (53%) and unrelated (47%). Median follow-up of surviving patients (n = 43) was 29.4 months (range, 13.1-87.7). The complete remission (CR) rate was 82%. Estimates of 2-year survival were 66%, 40%, and 23% for patients in CR, with active disease without and with circulating blasts at HSCT, respectively. In multivariate analysis, survival was negatively influenced by active disease at HSCT and development of grade II-IV acute GVHD. Presence of circulating blasts at HSCT negatively influenced freedom from disease progression. Incidence of nonrelapse mortality (NRM) was significantly higher for patients with active disease, but was not influenced by patient age. Patients in CR had a day-100 and 2-year NRM of 0% and 20%, respectively. Use of unrelated donors increased the risk of NRM only among patients with active disease. FM and HSCT elicited long-term disease control in a significant fraction of this high-risk cohort.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Transplante de Células-Tronco Hematopoéticas/métodos , Leucemia Mieloide Aguda/terapia , Síndromes Mielodisplásicas/terapia , Condicionamento Pré-Transplante/métodos , Adulto , Idoso , Progressão da Doença , Quimioterapia Combinada , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Melfalan/administração & dosagem , Pessoa de Meia-Idade , Fatores de Risco , Sobreviventes , Transplante Homólogo , Vidarabina/administração & dosagem , Vidarabina/análogos & derivadosRESUMO
The expression and activity of P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP1) were analyzed in 178 leukemia samples. Rhodamine-123 (Rho-123) and DiOC(2) were used as substrate to evaluate efflux pump activity. Chronic myeloid leukemia (CML) exhibited a higher percentage of positivity using Rho-123 than DiOC(2) (p=0.000) as compared to other types of leukemia. Moreover, Rho-123 was able to detected Pgp positive cells in a higher proportion of samples than DiOC(2) samples (p=0.004). Similarly, MRP1 positive cells were best detected by Rho-123 as opposed to DiOC(2) (p=0.003). The co-functionality of Rho-123 and DiOC(2) was observed in 26 out of 105 (24.8%) leukemic samples. Co-expression between Pgp and MRP1 was detected in 30 out of 56 (53.6%) samples. As a whole, when the same samples were analyzed, Rho-123 was able to detect Pgp positive cells in a higher proportion of samples than DiOC(2) (p=0.000). Similarly, MRP1 positive cells were best detected by Rho-123 as opposed to DiOC(2) (p=0.007). Our results support the idea that Rho-123 is the substrate of choice for leukemic cells.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Corantes Fluorescentes/metabolismo , Leucemia/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Carbocianinas/metabolismo , Citometria de Fluxo , Humanos , Leucemia/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/metabolismo , Fenótipo , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Rodamina 123/metabolismo , Células Tumorais CultivadasRESUMO
With the currently available commercial kits, as well as homemade assays for detecting anticardiolipin antibodies (aCL), it is not possible to discriminate nonpathogenic, beta 2 glycoprotein (GPI)-independent, infection-related antibodies from those of patients with the true autoimmune thrombotic syndrome, known as antiphospholipid syndrome (APS). We devised an assay that is able to differentiate these two types of antibodies by determining the beta 2 GPI requirements to bind in a cardiolipin ELISA. Beta 2 GPI was purified by perchloric acid precipitation, and fixed amounts were used in the dilution solutions of the tested samples that were also tested with no source of beta 2 GPI. The ELISA plates were coated with cardiolipin, as usual, and blocked with a chicken ovalbumin solution. The serum samples had to be highly diluted in order not to have beta 2 GPI from the patient serum. The reaction was detected with alkaline phosphate tablets and developed with pNp in diethanolamine buffer. The adapted ELISA aCL assay described here was able to discriminate infectious [syphilis, hepatitis C virus (HCV), dengue fever, human immunodeficiency virus (HIV) and leprosy] and autoimmune [primary APS and systemic lupus erythematosus (SLE) related APS]. Further testing should be performed to demonstrate that this method consistently differentiates pathogenic antibodies that bind in an aCL ELISA only in the presence of beta 2 GPI.
Assuntos
Anticorpos Anticardiolipina/imunologia , Anticorpos Antifosfolipídeos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Glicoproteínas/química , Animais , Anticorpos Anticardiolipina/química , Anticorpos Antifosfolipídeos/química , Síndrome Antifosfolipídica/diagnóstico , Cardiolipinas/química , Humanos , beta 2-Glicoproteína IRESUMO
PURPOSE: To treat non-Hodgkin's B-cell lymphoma (B-NHL) in children with manageable toxicity-related morbidity and without any decrease in survival. PATIENTS AND METHODS: Between January 1998 and April 2003, 53 consecutive patients (age 16 years or less) from a single institution were enrolled. The patients were stratified by risk factors (stage and LDH level) and treated with a BFM 86/90 (Berlin-Frankfurt-Münster)-based protocol with reduction of the methotrexate dose from 5 mg/m to 2 mg/m. RESULTS: The mean age of the patients was 6 years (range 1-16 years). Seventy-two percent of the patients had lymphomas classified as Burkitt type, 11% as diffuse large cell lymphoma, and 6% as Burkitt-like lymphoma, and 11% were not classified. At a median follow-up of 35 months, 44 patients (83%) survived in complete remission. The event-free survival rate for all patients was 78% (SE = 0.07): 100% (SE = 0.0) for stage I/II patients and 74% (SE = 0.08) for stage III/IV patients. Six patients suffered initial treatment failure and one patient relapsed, all of whom died. There was only one death from sepsis related to treatment. CONCLUSIONS: This strategy was very effective for treating B-NHL in a developing country. The results were comparable to those of the BFM 90 study and other contemporary groups and represented an increase in the cure rates in childhood B-NHL in Brazil.
Assuntos
Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Asparaginase/uso terapêutico , Daunorrubicina/uso terapêutico , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/mortalidade , Prednisona/uso terapêutico , Vincristina/uso terapêutico , Adolescente , Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Asparaginase/efeitos adversos , Brasil , Criança , Pré-Escolar , Daunorrubicina/efeitos adversos , Feminino , Humanos , Lactente , Masculino , Estadiamento de Neoplasias , Prednisona/efeitos adversos , Fatores de Risco , Análise de Sobrevida , Resultado do Tratamento , Vincristina/efeitos adversosRESUMO
OBJECTIVES: The TP53 gene encodes a nuclear protein implicated in the regulation of the cell cycle, DNA repair, and apoptosis. TP53 mutations and other alterations have been described in numerous types of tumors, and some of these have been associated with poor prognosis. The aim of this study was to characterize TP53 mutations in childhood B non-Hodgkin's lymphoma, their correlation with clinical prognostic factors and response to therapy. PATIENTS AND METHODS: Samples from 49 children with B non-Hodgkin's lymphoma were examined for TP53 alterations by single-strand conformation polymorphism analysis (SSCP) of exons 5-9, direct sequencing and by p53 immunohistochemistry. RESULTS: Mutations of TP53 were detected in 11 of 49 (22.5%) patients and more specifically in 20% of Burkitt's lymphoma. The sequence analysis showed missense mutations in 10 cases and an insertion mutation in one case. Mutations of the transition type occurred more frequently than transversions (seven of 11). Analysis of the spectrum of single-nucleotide substitutions showed a 30% frequency of transition mutations in CpG dinucleotide sequences. The overall frequency of p53 immunostaining positivity was 36% (15 of 41). There was a very good agreement between protein expression and the presence of TP53 mutation (P=0.0005). No significant correlation was found regarding age, gender, clinical stage and LDH level and TP53 mutations. Comparison of EFS curves using the log-rank test were also not significant. However, the analysis of the effects of mutations on the core p53 structure identified biological and biochemical mutants with phenotypes probably related to different response to chemotherapy. CONCLUSIONS: Our data suggest that some types of mutants can alter the protein distinctly and may be associated with a more aggressive phenotype. In addition, the impact of TP53 mutations on response to therapy may also be influenced by disruption of other genes.