Molecular cytogenetics localizes two new breakpoints on 11q23.3 and 21q11.2 in myelodysplastic syndrome with t(11;21) translocation.

Translocation t(11;21)(q24;q11.2) is a rare but recurrent chromosomal abnormality associated with myelodysplastic syndrome (MDS) that until now has not been characterized at the molecular level. We report here results of a molecular cytogenetic analysis of this translocation in a patient with refractory anemia.

Genomic organization of human JAK2 and mutation analysis of its JH2-domain in leukemia.

The Janus kinase family of proteins, with four mammalian members (JAK1, JAK2, JAK3 and TYK2), plays an essential role in the signal transduction pathway from non-catalytic cytokine receptors to the nucleus. We recently reported the involvement of ETV6-JAK2 fusion genes in the development of leukemia of both lymphoid and myeloid origin. Dominant missense mutations of hopscotch, a Drosophila JAK homologue, causing leukemia-like defects were described.

Identification of multiple copies of a 20q-chromosome in a case of myelodysplastic syndrome: a FISH study.

In myelodysplastic syndromes (MDS) karyotypic aberrations identify subgroups of patients with distinct clinical-morphological features and can be relevant in risk assessment of developing leukemia. Often conventional cytogenetic analysis is not sufficiently informative due to the presence of partially or completely unrecognizable chromosome markers. By chromosome microdissection (MD) and fluorescence in situ hybridization (FISH) we investigated the nature of a karyotypic marker occurring in multiple copies in one case of MDS arisen in a patient previously treated for breast cancer.

New reciprocal translocation t(5;10)(q33;q22) associated with atypical chronic myeloid leukemia.

We report a new chromosomal reciprocal translocation t(5;10)(q33;q22) in a 49-year-old man with atypical chronic myeloid leukemia (a-CML) and history of occupational exposure to petroleum products including benzene and other hydrocarbons. The t(5;10) (q33;q22) was found in 94% and 84% of metaphases in peripheral blood and bone marrow cells, respectively. Cytogenetic analysis of single colonies derived from granulocyte-macrophage (CFU-GM), and erythroid (BFU-E) hematopoietic progenitors showed that 88% and 40% of CFU-GM and BFU-E, respectively, had the t(5;10)(q33;q22).

Genomic instability and recurrent breakpoints are main cytogenetic findings in Hodgkin's disease.

Background And Objective: Successful cytogenetic studies in Hodgkin's disease (HD) are rare, and, except for hyperdiploidy, no chromosome changes typical for this disorder have been described. The purpose of this study was to collect cytogenetic information from a new series of lymphoid neoplasms diagnosed either as classical HD or as Hodgkin's-like anaplastic large cell lymphoma (HD-like ALCL), according to the REAL Classification.

Design And Methods: We studied 27 cases of HD and 10 cases of HD-like ALCL.

Cytogenetics of myelodysplastic syndromes.

This review focuses on karyotypic and molecular findings of myelodysplastic syndromes (MDS). Genetic entities are distinct on the basis of structural (deletions, translocations, inversions) or numerical chromosomal abnormalities (trisomies, monosomies). New information about the amount and nature of malignant cells in MDS, as well as of genes rearranging in specific translocations, recently provided by molecular cytogenetics, are analysed.

Involvement of MLL gene in a t(10;11)(q22;q23) and a t(8;11)(q24;q23) identified by fluorescence in situ hybridization.

We describe two cases of acute myeloblastic leukemia, classified as M4 and M5 in the French-American-British nomenclature, with an 11q23 rearrangement at karyotypic analysis. The involvement of the MLL gene with two new partner loci on chromosome 10q22 and 8q24, respectively, was demonstrated by fluorescence in situ hybridization using a YAC clone B22B2L.

Interstitial insertion of AF10 into the ALL1 gene in a case of infant acute lymphoblastic leukemia.

The ALL1 gene at 11q23 is a promiscuous gene participating in chromosomal abnormalities of acute leukemias with 1 of over 30 potential partner genes. Among these, the AF10 gene at band 10p12 has been recently cloned and characterized. Acute leukemias with the ALL1/AF10 chimeric gene frequently show heterogeneity in the breakpoints on 10p, as well as complex insertion (10;11) as a result of complex molecular mechanisms leading to the ALL1/AF10 fusion.

Rearrangement between the MYH11 gene at 16p13 and D12S158 at 12p13 in a case of acute myeloid leukemia M1 (AML-M1).

A case of acute myeloid leukemia (AML) M1 with bone marrow eosinophilia was characterized by cytogenetics and fluorescence in situ hybridization (FISH). A complex karyotype including a der(12)t(12;17)(p12-13;q11) and a der(16)t(16;20)(p13;p11) was found at diagnosis. FISH studies with probes for chromosome 16 and for the short arm of chromosome 12 showed even more complex rearrangements.

Trisomy 6 is the hallmark of a dysplastic clone in bone marrow aplasia.

Clonal hematopoiesis with trisomy 6 as the sole karyotypic change was revealed by cytogenetics in two cases of aplastic anemia. In both patients, dyserythropoiesis was characterized by asynchrony of maturation between nucleus and cytoplasm, binucleated elements, and intercytoplasmic connections. In addition to conventional cytogenetics, the size of the trisomic clone was evaluated by fluorescence in situ hybridization on fixed cells at diagnosis and in the course of the disease by using an alpha-satellite centromeric probe for chromosome 6.

Molecular features of primary MDS with cytogenetic changes.

Cytogenetic changes in primary myelodysplastic syndromes (MDS) have been extremely useful to identify clonality and to define specific clinico-pathological entities. More recently, with the development of DNA technology, a bulk of new information has been added to classical cytogenetics. Genes corresponding to chromosomal breakpoints implicated in reciprocal translocations have been cloned.

Detection and monitoring of trisomy 8 by fluorescence in situ hybridization in acute myeloid leukemia: a multicentric study.

Background And Objective: The role of fluorescence in situ hybridization (FISH) in the detection and monitoring of trisomy 8 (+8) in acute myelogenous leukemia (AML) has not been defined exactly. This multicentric study was performed in order to: i) analyze the sensitivity of interphase FISH with respect to conventional chromosome analysis (CCA) in detecting +8; ii) compare the results of FISH and CCA in the quantitation of the frequency of +8-positive cells; iii) analyze the possible role of FISH in the cytogenetic follow-up of patients with +8.

Design And Methods: One hundred and ninety-eight nonconsecutive patients with a diagnosis of AML seen at five centers over a 3-year period were studied by CCA and FISH with a chromosome 8-specific centromeric probe.

Diagnosis, classification, and cytogenetics of myelodysplastic syndromes.

Background And Objective: The diagnosis of myelodysplastic syndromes (MDS) is essentially morphological and based on the presence of dysplastic features in the peripheral blood and bone marrow. The French-American-British (FAB) Cooperative Group proposed a classification based on easily obtainable laboratory information. In spite of some limitations, the FAB criteria have been useful for a long time.

Fluorescence in situ hybridization characterization of new translocations involving TEL (ETV6) in a wide spectrum of hematologic malignancies.

The ETV6 (also known as TEL) gene on chromosome 12p13 is the target of a number of translocations associated with various hematologic malignancies. The contribution of ETV6 to leukemogenesis occurs through different mechanisms that involve either its helix-loop-helix dimerization domain or its E26 transformation-specific (ETS) DNA-binding domain. Using fluorescence in situ hybridization we characterized seven new ETV6 rearrangements in chronic myeloid leukemia, acute myeloid leukemia, acute lymphoblastic leukemia, and non-Hodgkin's lymphoma.

Molecular delineation of 13q deletion boundaries in 20 patients with myeloid malignancies.

Fluorescent in situ hybridization (FISH) analysis with a panel of DNA probes for 13q13.1-q14.3 was performed on 20 cases of myeloid malignancies, of which 17 showed a del(13)(q) and three had translocations affecting 13q.

FISH identifies different types of duplications with 12q13-15 as the commonly involved segment in B-cell lymphoproliferative malignancies characterized by partial trisomy 12.

Clinical, cytogenetic, fluorescence in situ hybridization (FISH), and Southern blot data of 18 patients with different subtypes of B-cell non-Hodgkin's lymphoma, cytogenetically characterized by partial trisomy 12, are presented. These chromosomal changes occurred predominantly in clinically progressive chronic lymphocytic leukemia, mixed cell type, and advanced-stage follicle center cell lymphoma at the time of relapse or transformation into diffuse large cell lymphoma. Partial trisomy 12 consistently included the long arm of chromosome 12, either completely or partially, and resulted from dup(12q) or other rearrangements involving chromosome 12.

Philadelphia-like translocation t(9;22)(q34;q11) found in a follicular lymphoma involving not BCR and ABL but IGL-mediated rearrangement of an unknown gene on 9q34.

In a case of follicular center cell lymphoma (FCCL) without evidence of histologic progression towards a high-grade lymphoma, t(9;22)(q34;q11) was found simultaneously with a t(14;18)(q32;q21) and a t(8;14)(q24;q32). Molecular studies of this case showed BCL2 and MYC rearrangements in addition to the rearrangements of immunoglobulin heavy (IGH) and lambda (IGL) loci. Investigation of the t(9;22) using Southern blot and RT-PCR analysis failed to detect M-bcr or m-bcr rearrangements of BCR.

Identification of chromosome changes in acute myeloid leukemia (AML-M2) by molecular cytogenetics.

Karyotyping with fluorescence in situ hybridization (FISH) is reported in two rare cases of AML-M2 FAB. In the first case FISH analysis confirmed the presence of a t(7;11)(p15:p15) translocation in a complex karyotype that also showed an unbalanced translocation involving the other chromosome 7, a rare rearrangement between chromosomes 9 and 20, and four or five copies of a small marker derived from chromosome 9. In the second case whole chromosome painting with probes for chromosomes 8, 14, and 21 revealed the presence of a masked t(8;21) translocation in which one chromosome 14 was involved in a newly discovered rearrangement, i.

Further characterization of morphologically defined typical and atypical CLL: a clinical, immunophenotypic, cytogenetic and prognostic study on 390 cases.

We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low-risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I-II), usually required immediate treatment and their survival was shorter.

A new subtype of pre-B acute lymphoblastic leukemia with t(5;12)(q31q33;p12), molecularly and cytogenetically distinct from t(5;12) in chronic myelomonocytic leukemia.

Translocation t(5;12)(q33;p13), resulting in an ETV6/PDGFRB gene fusion, is a recurrent chromosomal abnormality associated with chronic myelomonocytic leukemia (CMML). An analogous translocation was also found in four cell lines with features of pre-B acute lymphoblastic leukemia (ALL). Using fluorescence in situ hybridization (FISH) we show here that in three of these cell lines identical complex rearrangements occurred.

del(7q) in chronic B-cell lymphoid malignancies.

Twelve patients with diagnosis of B-cell non-Hodgkin's lymphoma/leukemia and del[7q] were studied for their clinical, cytogenetic, and molecular characteristics. Eleven patients were classified as small cell lymphoma whereas one had a diffuse large cell lymphoma. Lymphoplasmacytic features were observed in six out of eleven small cell lymphomas.

Primary effusion Burkitt's lymphoma with t(8;22) in a patient with hepatitis C virus-related cirrhosis.

Hepatitis C virus (HCV) infection may be complicated by non-Hodgkin's lymphoma through yet unknown pathogenetic mechanisms. We describe the case of a patient with HCV-related cirrhosis who developed a primary effusion lymphoma (PEL) of Burkitt's type confined to the peritoneal cavity, in the absence of immunodeficiency or autoimmunity. Paracentesis followed by immunophenotyping, karyotyping, and molecular studies allowed us to diagnose a small noncleaved B-cell lymphoma (CD20+, CD24+, CD10+, CD5-, CD23-, lambda+) with the t(8;22) (q24;q11) translocation and clonal rearrangement of the immunoglobulin heavy chain gene.

ETV6 gene rearrangements in hematopoietic malignant disorders.

Chromosomal abnormalities involving the short arm of chromosome 12 have been frequently observed in a broad spectrum of hematological malignancies. Recently, a gene located in this chromosomal region and implicated in leukemogenesis was identified. The gene, called ETV6 (previously known as TEL) is a new member of the ETS family, a group of genes thought to act as transcriptional activators.

Successful use of the same slide for consecutive fluorescence in situ hybridization experiments.

The feasibility of using the same slide repeatedly for fluorescence in situ hybridization (FISH) experiments was systematically evaluated by applying standard procedures and various combinations of direct- and indirect-labeled probes to slides from patients with hematologic malignancies. Specific and distinct hybridization signals along with weak background signals and chromosome morphology of good to moderate quality could be obtained in up to three experiments performed consecutively on the same slide. Signals related to biotin- or digoxigenin-labeled probes applied in previous hybridizations were still visible with variable intensity, but interpretation problems that may result from this signal noise can be avoided by using adequate probes, detection systems and fluorochromes, and sequence of experiments.

ider(9)(q10)t(9;22)(q34;q11) is a recurrent chromosomal abnormality in acute lymphoblastic leukemia and lymphatic blastic phase of chronic myelogenous leukemia.

We report on two cases, one with acute lymphoblastic leukemia and a second with lymphatic blastic phase of Philadelphia chromosome-positive chronic myelogenous leukemia, cytogenetically characterized by ider(9)(q10)t(9;22)(q34;q11). Our findings and the data of the 4 cases previously published indicate that ider(9)(q10)t(9;22)(q34;q11) represents a rare but recurrent chromosomal abnormality occurring in hematological malignancies with lymphoid differentiation, namely acute lymphoblastic leukemia and lymphatic blastic phase of chronic myelogenous leukemia, and most likely evolves from a preexistent der(9) involved in the standard t(9;22).