Treatment of children with B-cell non-Hodgkin's lymphoma in developing countries: the experience of a single center in Brazil.

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.

Geographic variation in Epstein-Barr virus-associated Burkitt's lymphoma in children from Brazil.

In developing countries, BL has a strong association with EBV infection during childhood. In South America, the data have shown an EBV association intermediate between that reported in the United States (30%) and that in equatorial Africa (95%). Early age at EBV infection and lower socioeconomic status have been related to increased EBV-associated BL in developing countries. In Brazil, there are not enough data on childhood BL related to EBV infection. Our aim was to evaluate the clinicopathologic features and EBV association of 44 children with NHL from the state of Rio de Janeiro, situated in the southeast of Brazil. EBV was detected using RNA in situ hybridization in 36 biopsy specimens. DNA from fresh tumor samples and from paraffin-embedded tissues of patients were analyzed by PCR, in which the first reaction included primers for an EBNA-2 common region while the nested reaction amplified the region discriminating between EBV types 1 and 2 in separate reactions. EBV was detected in 21 of 29 BLs (72%), and type 1 virus infected the majority of EBV-positive BLs (18/21). There was a trend for younger age in children with EBV-positive BL compared to EBV-negative BL (median age 4 compared to 6 years, respectively; p = 0.056). Our study confirmed that in the southeast of Brazil BL had an intermediate association with EBV. A higher rate of EBV-associated BL was described in the northeast of Brazil. These differences are probably related to regional socioeconomic status. In conclusion, our study suggests that early infection with EBV in the background of a low socioeconomic condition associated with other environmental factors could contribute to BL in Brazil.

DNA sequence profile of TP53 gene mutations in childhood B-cell non-Hodgkin's lymphomas: prognostic implications.

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.

Burkitt-like lymphoma in an infant: a case report.

Childhood non-Hodgkin's lymphomas, including Burkitt and Burkitt-like, are rarely diagnosed in infants. A case of B-cell lymphoma in a 13-month-old girl with extensive abdominal disease, ascites, pleural effusion, and tumor lysis syndrome is reported. Phenotypic analysis showed a germinal center B-cell phenotype, and a B-cell clonality was confirmed by polymerase chain reaction. There was no evidence of Epstein-Barr and HIV infection. The case herein reported emphasizes the need for considering the diagnosis of lymphoma even in very young children.