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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite its clinical and histological heterogeneity, anaplastic large cell lymphoma (ALCL) is now a well-recognized clinicopathological entity accounting for 2% of all adult non-Hodgkin's lymphomas (NHL) and about 13% of pediatric NHL. Immunophenotypically, ALCL are of T cell (predominantly) or Null cell type; by definition, cases expressing B cell antigens are officially not included in this entity. The translocation (2;5)(p23;q35) is a recurring abnormality in ALCL; 46% of the ALCL patients bear this signature translocation. This translocation creates a fusion gene composed of nucleophosmin (NPM) and a novel receptor tyrosine kinase gene, named anaplastic lymphoma kinase (ALK). The NPM-ALK chimeric gene encodes a constitutively activated tyrosine kinase that has been shown to be a potent oncogene. The exact pathogenetic mechanisms leading to lymphomagenesis remain elusive; however, the synopsis of evidence obtained to date provides an outline of likely scenarios. Several t(2;5) variants have been described; in some instances, the breakpoints have been cloned and the genes forming a new fusion gene with ALK have been identified: ATIC-ALK, TFG-ALK and TPM3-ALK. Cloning the translocation breakpoint and identifying the ALK and NPM genes provided tools for screening material from patients with ALCL using various approaches at the chromosome, DNA, RNA, or protein level: positive signals in the reverse transcriptase-polymerase chain reaction (RT-PCR) and the immunostaining with anti-ALK monoclonal antibodies (McAb) serve as the most convenient tests for detection of the t(2;5) NPM-ALK since the fusion gene and ALK protein expression do not occur in normal or reactive lymphoid tissue. The wide range of NPM-ALK positivity reported in different series appears to be dependent on the inclusion and selection criteria of the ALCL cases studied. Overall, however, 43% of ALCL cases were NPM-ALK+ (83% of pediatric ALCL vs 31% of adult ALCL). Occasional non-ALCL B cell lymphomas (4%) with diffuse large cell and immunoblastic histology and Hodgkin's disease cases (3%) were NPM-ALK-, but these data are questionable. The aggregate results indicate that, in contrast to primary nodal (systemic) ALCL, the t(2;5) may be present in only 10-20% of primary cutaneous ALCL and rarely, if at all, in lymphomatoid papulosis, a potential precursor lesion; however, these 10-20% positive cases were not confirmed by anti-ALK McAb immunostaining and may represent an overestimate. Positivity for NPM-ALK is associated to various degrees with the following parameters: 44% and 45% of ALCL cases with T cell and Null cell immunophenotype, respectively, are positive, whereas only 8% of cases with a B cell immunoprofile are positive; the mean age of positive patients is significantly younger than that of negative patients; positive cases carry a better overall prognosis (but not in all studies). Recently, the homogenous category of ALK lymphoma ('ALKoma') has emerged as a distinct pathological entity within the heterogenous group of ALCL. The fact that patients with ALK lymphomas experience significantly better overall survival than ALK- ALCL demonstrates further that analysis of ALK expression has important prognostic implications. The term ALK lymphoma signifies a switch in the use of the diagnostic criteria: cases are selected on the basis of a genetic abnormality (the ALK rearrangement), instead of the review of morphological or immunophenotypical features which are clearly more prone to disagreement and controversy. Since its initial description in 1985 ALCL has become one of the best characterized lymphoma entities.
Leukemia 2000 Sep
PMID:Pathobiology of NPM-ALK and variant fusion genes in anaplastic large cell lymphoma and other lymphomas. 1099 99

CD56, a neural adhesion molecule, is a marker of natural killer (NK) lymphocytes as well as a subgroup of CD8+ T cells. Normal lymphocytes with a CD56/CD4 phenotype are scarce. Physiologic increases may occur in patients with immunosuppression, chronic inflammation, and autoimmune disorders. We report 4 cases of lymphomas/leukemias with the unusual CD56/CD4 phenotype. Two were of T-cell and 2 of true NK-cell origin. The T-cell lymphomas had large granular lymphocyte morphologic features and splenomegaly. One patients had a benign course; the other died within months of the leukemia diagnosis. The 2 NK cell lymphomas had blastic morphologic features, initially involved skin, and had a very aggressive clinical course; 1 patient died of acute leukemia, and 1 had recurrence after bone marrow transplantation. Cytogenetic analyses did not show a consistent pattern of abnormalities. The NK lymphoma with acute leukemia had a t(2;5) but was CD30- and anaplastic lymphoma kinase negative. Although CD56+/CD4+ lymphomas/leukemias are a heterogeneous group, there may be a distinct subgroup of NK lymphoblastoid lymphomas of the skin, judging from our cases, as well as those previously reported.
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PMID:CD56+/CD4+ lymphomas and leukemias are morphologically, immunophenotypically, cytogenetically, and clinically diverse. 1148 62

This report describes an unusual extramedullary hematologic malignancy in an 18-month-old child who presented with a capillary leak syndrome that evolved into hyperleukocytosis with malignant cells. The circulating tumor cells did not express an antigen profile typical of any subtype of leukemia commonly observed in children. Tumor cells were CD3(-)/CD56(+); had germline TCR genes; and strongly expressed CD30, epithelial membrane antigen, and anaplastic lymphoma kinase (ALK) consistent with a null cell anaplastic large cell lymphoma (ALCL). The malignant cells contained a t(2;19)(p23;p13.1) that interrupted ALK and translocated it to the der(19). Reverse transcriptase-polymerase chain reaction and nucleotide sequence analysis revealed fusion of ALK to tropomyosin 4, an ALK fusion partner not described previously in hematologic malignancies. The clinical presentation and phenotypic features of this malignancy were not typical for ALCL because tumor cells expressed both myeloid (CD13, CD33, HLA-DR) and natural killer (NK) cell antigens. The neoplastic cells most resembled NK cells because in addition to being CD3(-)/CD56(+) with germline TCR genes, these cells were CD25(+)/CD122(+)/granzyme B(+) and possessed the functional properties of immature NK cells. The unusual clinical presentation, immunophenotype, and functional properties of these neoplastic cells suggest that this malignancy may be derived from the putative myeloid-NK precursor cell. Furthermore co-expression of NK and ALCL features supports the concept that a minority of null-ALCL may be derived from NK cells and expands the spectrum of phenotypes that can be seen in tumors produced by ALK fusion proteins. (Blood. 2001;98:1209-1216)
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PMID:Unusual childhood extramedullary hematologic malignancy with natural killer cell properties that contains tropomyosin 4--anaplastic lymphoma kinase gene fusion. 1149 72

This review covers the diagnosis and management of natural killer and peripheral T-cell lymphomas (PTCL). Problems with PTCL include their rarity, representing usually 10-15% of non-Hodgkin's lymphomas in the Western Hemisphere, morphologic heterogeneity, and lack of immunophenotypic markers for clonality. Additionally, their clinical behavior is variable and may not correlate with morphology. Dr. Kinney gives a general overview of the diagnosis of PTCL and NK cell neoplasms. Emphasis will be placed on extranodal T cell and natural killer (NK) cell lymphomas such as hepatosplenic lymphoma, subcutaneous panniculitis-like lymphoma and nasal/nasal type T/NK-cell lymphoma. The use of ALK gene regulation in the classification of anaplastic large cell lymphoma is also reviewed. Dr. Loughran describes current understanding of the pathogenesis of large granular lymphocyte (LGL) leukemia. The discussion focuses on LGL leukemia as an instructive model of dysregulated apoptosis causing both malignant and autoimmune disease. Current management options and mechanisms of therapeutic response are also described. Dr. Greer addresses whether PTCL should be treated differently from the more common diffuse large B cell lymphomas. He discusses the therapeutic options for anaplastic large cell lymphoma (ALCL), from a conservative approach for primary cutaneous ALCL to combination chemotherapy for the highly chemosensitive ALCL expressing anaplastic lymphoma kinase. He reviews therapy options for the extranodal subtypes of PTCL by drawing from series in adults, pediatrics, dermatology, and the Far East.
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PMID:T cell and NK cell lymphoproliferative disorders. 1172 88

Acquired chromosomal anomalies (most commonly translocations) in lymphoma and leukemia usually result in either activation of a quiescent gene (by means of immunoglobulin or T-cell-receptor promotors) and expression of an intact protein product, or creation of a fusion gene encoding a chimeric protein. This review summarizes current immunocytochemical studies of these 2 categories of oncogenic protein, with emphasis on the clinical relevance of their detection in diagnostic samples. Among the quiescent genes activated by rearrangement, expression of cyclin D1 (due to rearrangement of the CCND1 [BCL-1] gene) is a near-specific marker of t(11;14) in mantle cell lymphoma; BCL-2 expression distinguishes follicular lymphoma cells from their nonneoplastic counterparts in reactive germinal centers and appears to be an independent prognostic marker in diffuse large cell lymphoma; and TAL-1 (SCL) expression identifies T-cell acute lymphoblastic neoplasms in which this gene is activated. The protein products of other genes activated by chromosomal rearrangement have a role as markers of either lineage (eg, PAX-5 [B-cell-specific activator protein] for B cells, including B-lymphoblastic neoplasms), or maturation stage (eg, BCL-6 for germinal-center and activated B cells and MUM-1/IRF4 for plasma cells). Currently, no hybrid protein encoded by fusion genes is reliably detectable by antibodies recognizing unique junctional epitopes (ie, epitopes absent from the wild-type constituent proteins). Nevertheless, staining for promyelocytic leukemia (PML) protein will detect acute PML with t(15;17) because the microspeckled nuclear labeling pattern for PML-RARalpha is highly distinctive. Similarly, antibodies to the anaplastic lymphoma kinase (ALK) tyrosine kinase are valuable (because wild-type ALK is not found in normal lymphoid tissue) in detecting neoplasms (CD30-positive large T-cell lymphomas) with t(2;5) or its variants. Thus, immunocytochemical detection of the products of many rearranged genes in lymphoma and leukemia can be clinically informative and provide information on cellular and subcellular protein expression that cannot be inferred from studies based on messenger RNA.
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PMID:Proteins encoded by genes involved in chromosomal alterations in lymphoma and leukemia: clinical value of their detection by immunocytochemistry. 1178 Dec 20

Peripheral (post-thymic) T-cell lymphoma consists of a wide spectrum of disorders with marked differences in biology and behavior. Proper classification is pivotal for evaluating treatment results, and most studies performed a decade ago lump together different disease entities and cannot be interpreted. With improved use of immunophenotyping and molecular methods for these disorders, their exact nature is better defined in the Revised European-American Lymphoma and subsequent World Health Organization (WHO) classifications. The WHO classification of post- thymic T/natural killer (NK)-cell lymphoma consists of 15 entities, including about 30% that are unclassified cases. A wide range in incidence exists between different populations, but it is likely to be lower than previously estimated. Certain entities, like nasal/nasal-type T/NK-cell lymphoma and human T-cell leukemia/lymphoma virus 1, are much more prevalent in certain racial groups and show exquisite viral association. In these entities as a group, prognosis and treatment seem inferior to those of their B-cell counterparts, but treatment must be tailored to the exact pathologic diagnosis and prognostic index. Aggressive combination chemotherapy appears to be curative for certain entities (eg, anaplastic lymphoma kinase-positive), whereas purine analogues may be useful for low-grade entities. The role of autologous and allogeneic stem cell transplantation is still poorly defined. Specific antibody-based therapy is also on the horizon.
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PMID:Peripheral T-cell lymphoma. 1216 19

Peripheral T-cell lymphoma primary to the central nervous system is a rare occurrence. The authors report a case of an 89-year-old woman who presented with a 3-month history of worsening confusion and recent onset of headache, nausea and vomiting, and upper limb tremors. Computed tomography and magnetic resonance imaging examinations demonstrated a 4.5-cm solitary brain mass in the right basal ganglia with compression along the ventricular system. No other lesion was found in the patient. Histologic and immunohistochemical studies of a stereotactic biopsy of the mass showed a T-cell lymphoproliferative lesion positive for CD3, CD8, CD57, and T-cell intracellular antigen 1 and negative for CD4, CD56, CD30, anaplastic lymphoma kinase, and CD20. A monoclonal T-cell receptor-gamma gene rearrangement was detected by polymerase chain reaction analysis of genomic DNA isolated from paraffin-embedded tumor tissue sections. These findings were consistent with peripheral T-cell lymphoma of cytotoxic/suppressor phenotype, resembling the phenotype of T-cell large granular cell leukemia. To the authors' best knowledge, this represents the first reported case of primary brain T-cell lymphoma with a cytotoxic/suppressor immunophenotype. A brief review of the literature of primary brain T-cell lymphoma is also presented.
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PMID:Primary central nervous system cytotoxic/suppressor T-cell lymphoma: report of a unique case and review of the literature. 1271 53

The World Health Organization (WHO) classification of malignant lymphoma presented a list of disease entities well defined by clinical, immunological and genetic features. Therefore, the current diagnosis of peripheral T/NK-cell lymphomas (PTNKLs) essentially requires the inclusion of anatomical sites of disease and phenotypical features. We analyzed 408 Japanese cases of PTNKLs in order to clarify the relationship between anatomical sites of disease and phenotypical features and to translate the functional subsets of T and NK cells into their diagnoses for further understanding lymphomatic biology. The T/NK-cell lymphoma entities were allocated into three categories: (i) cytotoxic memory T-cell and/or NK-cell lymphoma (n = 151) consisting of extranodal NK/T-cell tumors other than mycosis fungoides (MF); (ii) non-cytotoxic memory T-cell lymphoma (n = 142) consisting of nodal and cutaneous tumors such as angioimmunoblastic T-cell lymphoma, adult T-cell lymphoma/leukemia and MF; and (iii) anaplastic lymphoma kinase positive anaplastic large cell lymphoma (n = 110) that has unique features and might be regarded as cytotoxic 'naive' T-cell lymphoma. Overall, these three categories were significantly correlated with age of onset, anatomical sites, the level of expression of cytotoxic molecules and CD45RO, and association with Epstein-Barr virus. This concept might provide a new insight enabling further understanding of the interrelationships among WHO T/NK-cell disease entities.
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PMID:Phenotypic analysis of peripheral T/NK cell lymphoma: study of 408 Japanese cases with special reference to their anatomical sites. 1278 7

Down syndrome is the most common birth defect associated with mental retardation. Identifying proteins that are aberrantly expressed therefore helps to understand how chromosomal imbalance leads to subnormal intelligence in Down syndrome. In the present study, we generated a fetal brain map with the use of an analytical method based on two-dimensional electrophoresis coupled with mass spectrometry and searched the proteome for differential protein expression. Among 49 proteins analyzed in seven control and nine Down syndrome fetuses, we found 11 proteins that have been deregulated in cerebral cortex of fetal Down syndrome. While double-strand break repair protein rad 21 homologue, eukaryotic translation initiation factor 3 subunit 5, mixed lineage leukemia septin-like fusion protein-B and heat shock protein 75 were increased; beta-amyloid precursor-like protein 1, tropomyosin 4-anaplastic lymphoma kinase fusion oncoprotein type 2, Nck adaptor protein 2, Src homology domain growth factor receptor bound 2-like endophilin B2, beta tubulin, septin 7 and hematopoietic stem/progenitor cells 140 were decreased. The current data suggest that misexpression of proteins that have functions ranging from signaling to cellular structural organization could contribute to or reflect brain dysgenesis in Down syndrome.
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PMID:Aberrant protein expression in cerebral cortex of fetus with Down syndrome. 1459 56

Using a cDNA microarray, we found that suppressor of cytokine signaling 3 (SOCS3) is highly expressed in anaplastic lymphoma kinase (ALK)+ anaplastic large cell lymphoma (ALCL) cell lines. As SOCS3 is induced by activated signal transducer and activator of transcription 3 (STAT3), and ALK activates STAT3, we hypothesized that SOCS3 may play a role in ALK+ ALCL pathogenesis via the Janus kinase 3 (JAK3)-STAT3 pathway. Using ALCL cell lines, we show by coimmunoprecipitation experiments that SOCS3 physically binds with JAK3 in vitro, and that JAK3 inhibition by WHI-P154 downregulates SOCS3 expression. Western blot analysis confirmed expression of SOCS3 and also showed coexpression of phosphorylated (activated) STAT3 (pSTAT3). Direct sequencing of the SOCS3 gene showed no mutations or alternative splicing. In ALCL tumors that were assessed by immunohistochemistry, nine of 12 (75%) ALK+ tumors were SOCS3 positive and eight (67%) coexpressed pSTAT3. In comparison, 18 of 25 (72%) ALK-- tumors were SOCS3 positive and seven (28%) coexpressed pSTAT3. These results show that SOCS3 is overexpressed in ALCL, attributable to JAK3-STAT3 activation and likely related to ALK in ALK+ tumors. However, SOCS3 is also expressed in tumors that lack STAT3 and ALK suggesting alternative mechanisms of upregulation.
Leukemia 2004 Nov
PMID:Suppressor of cytokine signaling 3 expression in anaplastic large cell lymphoma. 1538 32


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