Similar mechanisms formed ring markers containing chromosome 12 pericentromeric region in two patients with therapy-related acute myeloid leukemia.

Two cases of therapy-related acute myeloid leukemia showed complex karyotypes, including a small ring and a larger D-chromosome. Multicolor fluorescence in situ hybridization and bacterial artificial chromosome and fosmid clones showed that both ring chromosomes were composed entirely of material excised from chromosome 12. The deleted segment of 12 was found fused to the short arm of a D-group chromosome. We hypothesized that similar mechanisms were involved in both rearrangements. A fusion at the short arms of chromosome 12 and a D-group chromosome was accompanied by excision and ligation of the chromosome 12 pericentromeric region to form a small ring chromosome.

Recurrent rearrangement of the Ewing's sarcoma gene, EWSR1, or its homologue, TAF15, with the transcription factor CIZ/NMP4 in acute leukemia.

Fusions of the TET-proteins (TLS/FUS, EWSR1, and TAF15/RBP56) to different transcription factors are involved in various malignancies including Ewing's sarcoma, primitive neuroectodermal tumors, and acute myeloid leukemia. These are thought to arise through transcriptional deregulation, with the transcription factor defining the tumor phenotype. We show that, as result of a t(12;17)(p13;q11) or its variant t(12;22)(p13;q12), the transcription factor gene CIZ/NMP4 is recurrently involved in acute leukemia through fusion with either EWSR1 or TAF15. The fusions possess transforming properties in NIH3T3 cells but do not affect the expression of CIZ target genes, suggesting a contribution to oncogenesis that is independent of the transactivating properties of the fusion protein. These results also extend the involvement of TET-protein fusions to acute lymphoblastic leukemia and suggest a role for CIZ/NMP4 in lymphoid and myeloid development.

Low frequency of exon 3 PTPN11 mutations in adult de novo acute myeloid leukemia. Analysis of a consecutive series of 173 patients.

A total of 173 samples obtained from adult patients with de novo acute myeloid leukemia (AML) were assayed for exon 3 PTPN11 mutations by single strand conformation polymorphism (SSCP) analysis and direct sequencing. Only three monocytic leukemias had point mutations (1.73%).

Immunophenotypic findings in acute myeloid leukemia with FLT3 internal tandem duplication.

BACKGROUND AND OBJECTIVES: The biological characteristics and the prognostic significance of the internal tandem duplication of the FLT3 (FLT3/ITD) were investigated in a series of de novo acute myeloid leukemia (AML) patients. One hundred and fifty-six adult patients with AML were included in the study. FLT3/ITD was detected in 41 (26%) patients (FLT3/ITD(+)). DESIGN AND METHODS: The main differences observed between the groups with and without FLT3/ITD: a higher leukocyte count, a raised percentage of a normal karyotype and a more frequent M5 FAB diagnosis in the FLT3/ITD(+) patients. As regards the immunophenotype characteristics the FLT3/ITD(+) group very often expressed monocytic markers (CD36 and CD11b) and less commonly immature markers (CD34 and CD117). A promyelocytic-like immunophenotype pattern was also detected in a minority of these patients(4/36). RESULTS: The FLT3/ITD(+) patients had a shorter overall survival, a shorter event-free survival and a higher probability of relapse. Minimal residual disease (MRD) was investigated in the FLT3/ITD(+) patients using flow cytometry. This technique had a sensitivity of 62% and a specificity of 83% in relapse prediction. Minimal residual disease analysis was hampered by the low number of patients with detectable aberrant immunophenotype. INTERPRETATION AND CONCLUSIONS: A high frequency of changes in the phenotype and/or genotype pattern between diagnosis and relapse was detected (5/6). FLT3/ITD is a frequent molecular lesion in de novo adult AML and seems to be associated with a monocytic differentiation, a high leukocyte count and a poor prognosis. Immunophenotype and genotype patterns observed at relapse suggest that the FLT3/ITD(+) blasts may be genetically unstable and prone to clonal evolution. FLT3/ITD may not be a suitable target for minimal residual disease studies.

Submicroscopic deletions in 5q- associated malignancies.

BACKGROUND AND OBJECTIVES: The deletion of the long arm of chromosome 5 is common in myelodysplastic syndromes (MDS) but is not limited to the 5q- syndrome as it is also seen in acute myeloid leukemia (AML), where it is often associated with other karyotypic aberrations. The aim of this study was to investigate whether deletions of known suppressor sequences occur in myeloid malignancies associated with 5q-. DESIGN AND METHODS: Thirty patients with MDS or AML were selected for the presence of a 5q karyotypic deletion, either isolated (19 cases) or associated with other chromosome changes (11 cases). Multiple fluorescent in situ hybridization (FISH) in interphase nuclei was applied in all cases using a panel of eleven probes for known suppressor genes or loci deleted in MDS/AML. Metaphase FISH was also performed to clarify discrepancies between conventional and molecular cytogenetics. RESULTS: No additional deletions were found in nineteen cases with an isolated 5q-. Mono-allelic deletions where found in 9/11 cases, 3 of which were related to monosomies by conventional cytogenetics. Interphase-FISH showed p53, AML1, D13S25, NF1, or Ikaros in six out of nine (66%) patients with 5q- and additional karyotypic changes. Metaphase FISH was helpful in assigning some of these cryptic events to non-proliferating cells. INTERPRETATION AND CONCLUSIONS: Our study emphasizes that isolated 5q- is the marker of a highly stable clone in both MDS and AML. AML with isolated 5q- are molecularly closer to 5q- syndrome than to AML with complex changes. Interphase-FISH data strongly support a mutator phenotype underlying complex karyotypes with a 5q deletion.

Novel dic(16;18)(q11;p11) in two cases of Philadelphia chromosome positive acute B-cell lymphoblastic leukemia.

We report two adult patients with Philadelphia chromosome positive (Ph+) B-cell acute lymphoblastic leukemia (ALL) who presented an additional dic(16;18)(q11;p11) that, to the best of our knowledge, has never been previously reported. Fluorescence in situ hybridization analysis confirmed the translocation and showed it to be dicentric. Both patients were treated for the ALL, but showed refractory disease and died despite aggressive treatment. Similarly to what has been reported with other additional chromosome abnormalities, our cases suggest that the presence of this novel translocation confers an adverse effect to the already poor prognosis of Ph+ ALL.

[Persistent polyclonal B-cell lymphocytosis: study of 35 cases]. / Linfocitosis B policlonal persistente: estudio de 35 casos.

BACKGROUND AND OBJECTIVES: Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity, presenting especially in adult smoker women. It is characterized by an increase of serum IgM, DR7-HLA haplotype, cytogenetic abnormalities and multiple IgH/BCL-2 rearrangements. To date, it has not been elucidated whether this is a benign or premalignant disorder. We analyzed the PPBL characteristics with especial attention to its evolution. PATIENTS AND METHODS: Thirty-five PPBL patients from 5 hospitals in Catalonia were retrospectively analyzed. A simultaneous morphologic review of the blood smears was performed by members of the GCCH in a 16 multiple-observer optic microscope. Clinical and biological data were also analyzed. RESULTS: PPBL presents in the majority of cases with persistent polyclonal B-cell lymphocytosis and affects primarily smoker women. The morphologic hallmark, in absence of viral infections, is the presence of activated lymphocytes with bilobulated and/or cleaved nuclei, and nuclear pockets in the ultrastructural study. Increased serum IgM, HLA-DR7 haplotype, chromosomal abnormalities such as i(3)(q10) and multiple IgH/BCL-2 rearrangements were detected. Thirty-four out of 35 patients are alive after a median follow up of 70.7 months. One patient died because of lung adenocarcinoma and another developed a follicular lymphoma without relation to PPBL. CONCLUSIONS: PPBL has an asymptomatic and stable evolution, although it frequently presents genetic abnormalities. It remains unknown whether it is a premalignant entity, similar to monoclonal gammopathies of unknown significance. Hence, accurate cytologic diagnosis and follow-up are essential.

NUP98 is fused to the NSD3 gene in acute myeloid leukemia associated with t(8;11)(p11.2;p15).

Fusion between the NUP98 and NSD3 genes in a patient with acute myeloid leukemia associated with t(8;11)(p11.2;p15), is reported for the first time. The t(8;11)(p11.2;p15) was identified by classical cytogenetics. Fluorescence in situ hybridization (FISH) analysis revealed a split signal with a mix of BAC 118H17 and 290A12, indicating the translocation disrupted NUP98. FISH restriction at 8p11-12 showed a split of BAC 350N15. Molecular investigations into candidate genes in this BAC showed the NUP98 fusion partner at 8p11.2 was the NSD3 gene. To date the NSD3 gene has never been implicated in hematologic malignancies.

Linfocitosis B policlonal persistente: estudio de 35 casos / Persistent polyclonal B-cell lymphocytosis: study of 35 cases

Fundamento y objetivo: La linfocitosis B policlonal persistente (LBPP) es una entidad muy poco frecuente que se relaciona con el tabaquismo e incide especialmente en mujeres. Cursa con aumento de IgM sérica, asociación al haplotipo HLA-DR7, anomalías citogenéticas y múltiples reordenamientos de IgH/BCL-2. Todavía no está clara su naturaleza premaligna o benigna. El objetivo de este trabajo fue analizar las características de la LBPP con especial interés en su evolución. Pacientes y método: Se han estudiado retrospectivamente 35 LBPP de 5 hospitales catalanes. Se realizó una valoración morfológica de las extensiones de sangre por los miembros del Grup Català de Citologia Hematològica (GCCH) en un microscopio de 16 cabezales y se analizaron los datos clínicos y biológicos. Resultados: La LBPP se presentó, en la mayoría de los casos, como linfocitosis en mujeres fumadoras. El distintivo morfológico es la presencia de linfocitos de aspecto activado, en ausencia de enfermedades víricas recientes, y de linfocitos bilobulados y/o hendidos, y algunos con bolsillos nucleares observados por ultraestructura. En la mayoría de los casos estudiados se detectó: aumento policlonal de IgM, expresión del haplotipo HLA-DR7, anomalías cromosómicas como i(3)(q10) y múltiples reordenamientos de IgH/BCL-2. Con una mediana de seguimiento de 70,7 meses, 34 de los 35 pacientes permanecen asintomáticos y vivos, uno falleció por un adenocarcinoma de pulmón y otro desarrolló un linfoma folicular, sin demostración de relación alguna entre éste y la LBPP. Conclusiones: La LBPP presenta un curso estable y asintomático, y se acompaña con frecuencia de alteraciones genéticas. Se desconoce si es una situación premaligna, a semejanza de las gammapatías monoclonales de significado incierto. Por ello, es fundamental una correcta interpretación de la linfocitosis y un seguimiento evolutivo (AU)

Background and objectives: Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity, presenting especially in adult smoker women. It is characterized by an increase of serum IgM, DR7-HLA haplotype,cytogenetic abnormalities and multiple IgH/BCL-2 earrangements. To date, it has not been elucidatedwhether this is a benign or premalignant disorder. We analyzed the PPBL characteristics with especial attention to its evolution.Patients and methods: Thirty-five PPBL patients from 5 hospitals in Catalonia were retrospectivelyanalyzed. A simultaneous morphologic review of the blood smears was performed by members of the GCCH in a 16 multiple-observer optic microscope. Clinical and biological data were also analyzed. Results: PPBL presents in the majority of cases with persistent polyclonal B-cell lymphocytosis and affects primarily smoker women. The morphologic hallmark, in absence of viral infections, is the presence of activated lymphocytes with bilobulated and/or cleaved nuclei, and nuclear pockets in theultrastructural study. Increased serum IgM, HLA-DR7 haplotype, chromosomal abnormalities such asi(3)(q10) and multiple IgH/BCL-2 rearrangements were detected. Thirty-four out of 35 patients are alive after a median follow up of 70.7 months. One patient died because of lung adenocarcinoma and another developed a follicular lymphoma without relation to PPBL.Conclusions: PPBL has an asymptomatic and stable evolution, although it frequently presents genetic abnormalities. It remains unknown whether it is a premalignant entity, similar to monoclonal gammopathies of unknown significance. Hence, accurate cytologic diagnosis and follow-up are essential (AU)