Is p190 bcr-abl rearrangement necessary for acute transformation in some p210 CML of childhood?

Chronic myeloid leukemia (CML) is a rare disease in childhood which is almost exclusively associated with bcr-abl p210 (M-bcr) rearrangements. It has been suggested that co-expression of p190 and p210 may be a pathway of CML progression in adult patients. We report two cases of pediatric patients with a diagnosis of CML who presented co-expression of the p210 and p190 transcripts during progression to the blastic phase. The present data suggest that p190 may be a secondary event in at least some cases of childhood CML, suggesting an association with progression to a blastic crisis in these patients.

Use of simplified strategies to evaluate early treatment response in childhood acute lymphoblastic leukemia

Early treatment response assessment has become an import prerequisite in the selection therapy in childhood ALL. In this study we compare classical diagnostic factors and the significance of three simplified strategies, WBC count at day 7 and a simplified PCR methodology to minimal residual disease detection on days 14 and 28, to evaluate early treatment response in 84 consecutive children with ALL. The use of these simplified methods for the evaluation of early response, proved to be a good predictor of an unfavorable course in children with ALL and could be used as a stratification criterion in treatment protocols, specially in low-budget countries.

PCR detection of clonal IgH and TCR gene rearrangements at the end of induction as a non-remission criterion in children with ALL: comparison with standard morphologic analysis and risk group classification

BACKGROUND

The initial response to induction therapy is currently considered one of the most important prognostic factors in acute lymphoblastic leukemias (ALL). A series of methods for the detection of submicroscopic levels of residual disease in patients with ALL mainly based on PCR and immunophenotyping has been developed, demonstrating that the presence of high levels of residual disease at the end of induction therapy is an important, independent prognostic factor. We determined the usefulness of PCR detection of minimal residual disease using consensus primers as a non-remission criterion.

PROCEDURE

Bone marrow samples obtained from 49 children with ALL were analyzed at diagnosis and at the end of induction therapy for the detection of clonal IgH, TCRdelta, and TCRgamma rearrangements by PCR. The results were compared with those obtained by standard morphologic analysis and risk group classification.

RESULTS

Patients who had clonality detected at the end of induction showed a significantly higher recurrence rate and lower event-free survival than those without detected clonality (24.9% vs. 89.7%) (P < 0.0001). Multivariate analysis revealed that detection of clonality at the end of induction was the most important, independent prognostic factor when associated with age, number of white blood cells, and immunophenotyping.

CONCLUSIONS

PCR detection of clonality using consensus primers is a relatively simple technique that is able to identify patients with a high chance of recurrence, and shows a higher sensitivity and a better prognostic value than standard morphologic analysis and risk group classification, defining a new remission criterion. However, further multicentric prospective studies using this technique employing a larger number of cases are necessary to confirm these findings.

Minimal residual disease in Brazilian children with acute lymphoid leukemia: comparison of three detection methods by PCR

The minimal residual disease (MRD) detection by the polymerase chain reaction (PCR) in children with acute lymphoblastic leukemia has been pointed to be an adverse prognostic factor. Detection methods based on this technique using clone-specific primers are cumbersome and time consuming. The detection of monoclonal gene rearrangements of gamma T-cell receptors (TCRgamma) is a simpler although less sensitive method. In the present study, we analyzed the presence of MRD during four different phases of treatment (week 4; 3-6, 12-24 months, and end of treatment) in 34 Brazilian children with lymphoid leukemia by three detection methods based on the PCR technique: (1) using consensus primers for the detection of a clonal population for TCRgamma; (2) clone-specific primers for the junctional region of TCRgamma; and (3) a semi-nested reaction with an initial cycle with consensus primers followed by a second cycle with clone-specific primers. MRD presence was associated with a shorter event-free survival and was the major independent prognostic factor in most of the phases analyzed. The use of consensus primers for the detection of TCRgamma clonality, although less sensitive, proved to be a simpler, faster and less costly method whose positivity was associated with more than 90% relapse rates during all phases analyzed.

Prognostic significance of bi/oligoclonality in childhood acute lymphoblastic leukemia as determined by polymerase chain reaction

CONTEXT

The CDR-3 region of heavy-chain immunoglobulin has been used as a clonal marker in the study of minimal residual disease in children with acute lymphoblastic leukemia. Southern blot and polymerase chain reaction studies have demonstrated the occurrence of bi/oligoclonality in a variable number of cases of B-lineage acute lymphoblastic leukemia, a fact that may strongly interfere with the detection of minimal residual disease. Oligoclonality has also been associated with a poorer prognosis and a higher chance of relapse.

OBJECTIVES

To correlate bi/oligoclonality, detected by polymerase chain reaction in Brazilian children with B-lineage acute lymphoblastic leukemia with a chance of relapse, with immunophenotype, risk group, and disease-free survival.

DESIGN

Prospective study of patients outcome.

SETTING

Pediatric Oncology Unit of the University Hospital, Faculty of Medicine of Ribeirão Preto, University of São Paulo.

PARTICIPANTS

47 children with acute lymphoblastic leukemia

DIAGNOSTIC TEST

Polymerase chain reaction using consensus primers for the CDR-3 region of heavy chain immunoglobulin (FR3A, LJH and VLJH) for the detection of clonality.

RESULTS

Bi/oligoclonality was detected in 15 patients (31.9%). There was no significant difference between the groups with monoclonality and biclonality in terms of the occurrence of a relapse (28.1% versus 26.1%), presence of CALLA+ (81.2% versus 80%) or risk group (62.5% versus 60%). Disease-free survival was similar in both groups, with no significant difference (p: 0.7695).

CONCLUSIONS

We conclude that bi/oligoclonality was not associated with the factors investigated in the present study and that its detection in 31.9% of the patients may be important for the study and monitoring of minimal residual disease.

[Transient pancytopenia induced by parvovirus B19 in a child with hereditary spherocytosis]

OBJECTIVE: To describe the occurrence of transient pancytopenia induced by parvovirus B19 infection in a patient with hereditary hemolytic anemia and to discuss the importance of the diagnosis of this pathology.METHODS: Case report of a child whose diagnosis was made by polymerase chain reaction (PCR) and serology, and review of the literature.CLINICAL REPORT: A twelve year-old male patient with hereditary spherocytosis, presenting non-specific symptoms of an infectious syndrome followed by severe and transient pancytopenia, whose diagnosis was a parvovirus B19 infection.CONCLUSION: The diagnosis of parvovirus infection has a particular importance in hematology, especially on some morbid conditions, among them the hereditary hemolytic anemias. PCR is useful because of its rapidness and sensitivity on the specific diagnosis of this disease.

Analysis of the p53 gene by PCR-SSCP in ten cases of Wilms' tumor

CONTEXT

Mutations of the p53 tumor suppressor gene are the most frequent alterations observed in human neoplasias affecting adults. In pediatric oncology, however, they have seldom been identified. Wilms' tumor is a renal neoplasia commonly occurring in children and is associated with mutations of the WT1 gene. The correlation between Wilms' tumor and alterations of the p53 gene has not been well established, with a low frequency of mutations having been reported in this type of tumor. Mutation may be associated with advanced stage disease and unfavorable histology.

OBJECTIVE

To screen for mutations of the p53 gene by the PCR-SSCP method and DNA sequencing in cases of Wilms' tumor sug-gestive of mutation.

DESIGN

Case Report.

CASE REPORT

Evaluations of exons 5-9 of the p53 gene in DNA samples extracted by PCR-SSCP from 10 Wilms' tumors in children at different stages, and DNA sequencing. Changes in SSCP analy-sis were observed in exon 8 in two samples. The probable muta-tions were not confirmed by DNA sequencing. The absence of point mutations in p53 gene observed in the 10 samples of Wilms' tumor studied agrees with literature data, with DNA sequencing being of fundamental importance for the confirmation of possible mutations.

Childhood B lineage acute lymphoblastic leukemia clonality study by the polymerase chain reaction

PURPOSE

B cell precursors acute lymphoblastic leukemia (ALL) present rearrangements in the heavy chain immunoglobulin and T cell receptor genes, especially in the complementarity determining region 3 (CDR-3) and T cell receptor delta (TCR delta) (V delta 2 D delta 3) regions. These rearrangements may be amplified by the polymerase chain reaction (PCR) and used as clonal markers of B lineage ALL. Our purpose was to study clonality at the DNA level by PCR in B lineage ALL.

PATIENTS AND METHODS

Fifty-three pediatric patients (36 with B lineage ALL, 7 with ALL-T, and 10 with nonlymphocytic disease) were investigated using consensus primers for the CDR-3 regions of IgH and TCR delta.

RESULTS

Clonality was detected in 86.1% of the patients with B lineage ALL when the primers for the CDR-3 regions were used, in 41.6% when the primers for TCR delta were used, and in 91.6% when the two primers were used together. Biclonality was found in 22.5% and 6.6% of patients that have shown clonality for CDR-3 and TCR delta, respectively. Clonality was not detected in any other samples using these primers.

CONCLUSIONS

PCR using CDR-3 and TCR delta primers can be used as an aid for B lineage ALL diagnosis and clonal evolution of theses disease.

Translocation (1;5)(q32;q35) in CD30+ anaplastic large cell non-Hodgkin lymphona of childhood. A case report

The authors studied cytogenetically a case of CD30+ anaplastic large cell non-Hodgkin lymphoma previously diagnosed as malignant histiocytosis and detected a translocation involving chromosomes 1 and 5, t(1;5)(q32:q35). After comparing their findings with those from reports in the literature, they comment about the importance of breakpoint q35 on chromosome 5 and point out the importance of associating morphologic, immunoperoxidase, and cytogenetic findings to confirm the diagnosis of this tumor.