Leukemia
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609 patients with B cell chronic lymphoproliferative disorder were studied with the primary aim of analyzing the cytogenetic profile of B cell chronic lymphocytic leukemias and, if possible, define correlations with FAB classification of these diseases. Morphological and immunological studies were performed according to criteria proposed by the FAB group. A panel of monoclonal antibodies, including at least sIg, CD19, CD5, and FMC7 was used. ⋯ Chronic lymphocytic leukemia was not statistically associated with any specific chromosomal abnormality. However, this subtype showed a high incidence of del(11)(q) and rearrangements of 13q. This study confirms the value of cytogenetic investigation in the diagnosis of these disorders and may provide some new elements for future refinement of the FAB classification in mature B cell lymphocytic disorders.
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Adult T cell leukemia (ATL) is the T cell malignancy caused by human T lymphotropic virus type I (HTLV-I), and HTLV-I is also the causative agent of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although HTLV-I causes both diseases, concomitant occurrence is reported to be rare. ⋯ This finding showed that the HTLV-I clone already existed at the stage of HAM/TSP. Since frequent detection of clonal proliferation of HTLV-I infected cells has been reported previously in patients with HAM/TSP, careful follow-up is needed for patients with HAM/TSP.
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To get more insight into the phenotypic changes of childhood acute lymphoblastic leukemia (ALL) at relapse, a detailed morphological and immunophenotypic study in 40 childhood ALL cases (32 precursor B-ALL and 8 T-ALL) was performed. Expression patterns of non-lineage specific markers (terminal deoxynucleotidyl transferase (TdT), CD34, and HLA-DR), B-lineage markers (CD10, CD19, CD20, and CD22), T-lineage markers (CD1, CD2, CD3, CD4, CD5, CD7, and CD8), and cross-lineage myeloid markers (CD14, CD15, and CD33) were compared at diagnosis and relapse. In case of low blast counts (< or = 70%) at relapse, double labeling for membrane markers and TdT was used in order to define the precise immunophenotype of the TdT+ leukemic cells. ⋯ In T-ALL, neither intra-lineage nor inter-lineage shifts were observed, although shifts were detected in all T cell markers tested, except for the lineage specific CD3 and T cell receptor (TcR) markers. In conclusion, immunophenotypic shifts at relapse frequently occur in precursor B-ALL and T-ALL, in a small percentage leading to an intra-lineage shift (10%) or inter-lineage shift (5%). Therefore immunophenotypic monitoring of minimal residual disease in ALL patients should be based on multiple marker combinations, preferably together with polymerase chain reaction analysis of rearranged immunoglobulin and/or TcR genes or chromosome aberrations.
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All-trans retinoic acid (ATRA) was used in a case of acute promyelocytic leukemia (APL) in late pregnancy. A very prompt maternal risk reduction was achieved with subsequent complete remission and spontaneous delivery of two live children in whom no fetal damage seems to have occurred.
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Comparative Study
Clonality studies and N-ras and p53 mutation analysis of hematopoietic cells in Fanconi anemia.
Patients with Fanconi anemia (FA) have an extraordinary predisposition to acute myelogenous leukemia (AML). The genetic mechanisms underlying the neoplastic transformation of FA hematopoietic cells are unknown. In this study, we have investigated the molecular features of hematopoiesis in the course of FA at different stages of the disease, including aplastic anemia, myelodysplastic syndrome (MDS), and AML. ⋯ Only normal N-ras and p53 sequences were detected in all cases analyzed. These results suggest that monoclonal hematopoiesis is a frequent finding in the course of FA and may precede the onset of neoplasia in some cases. The genetic mechanisms underlying FA-associated leukemogenesis appear to be independent of N-ras and p53 mutations, which are relatively frequent events in myeloid tumors associated with other hematologic disorders.