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

Experiments were undertaken to investigate a genetic event involved in leukemogenesis in adult T-cell leukemia (ATL). For this purpose, the p53 gene was chosen for study, since alteration of the gene has been found in a wide variety of human cancers. Structures and expression of the p53 gene in ATL cells were investigated by Southern and Northern blot analyses and a polymerase-chain-reaction single-strand conformation-polymorphism (PCR-SSCP) analysis. Either subtle alterations of the p53 gene or the absence of detectable level of p53 mRNA were found in 2 of 3 acute ATL cell lines and 2 of 12 acute ATL fresh samples. In contrast, no mutation was detected in 4 cases with less aggressive types of ATL (3 chronic and 1 smoldering ATL cases). Mutations found in acute ATL cells occurred in regions highly conserved in evolution and all the cells carrying p53 mutation showed loss of the other p53 allele. These results suggests that alteration of the p53 gene may contribute to progression of the disease in some cases of ATL.
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PMID:Adult T-cell leukemia: structures and expression of the p53 gene. 195 92

The 5C2 cell line was derived following culture of mouse spleen cells exposed in vivo and in vitro to radiation leukemia virus (RadLV) containing supernatants from the C6VL/1 T cell lymphoma. This cell line has been found to express an alpha beta T-cell receptor (TCR) identifiable with the Mab124-40 anti-clonotypic antibody which is specific for C6VL/1. It has been shown to be genetically and phenotypically distinct from C6VL/1 with a unique phenotype, i.e. CD4-, CD8-, CD3+, TCR-alpha beta. 5C2 has been shown to express high levels of alpha and beta chain mRNA and to utilize the same or similar V alpha and V beta region genes as C6VL/1. Whereas C6VL/1 binds cross-reactively to both RadLV/C6VL and an unrelated isolate RadLV/VL3, 5C2 has binding specificity for only RadLV/C6VL, which induced its proliferation. The anti-clonotypic antibody Mab124-40 specifically and completely inhibits binding of 5C2 to RadLV/C6VL at concentrations as low as 300 ng/ml. The 5C2 cell line can also be stimulated to increased proliferation by RadLV/C6VL. All of these data are consistent with the role of a TCR alpha beta heterodimer in binding and stimulation by RadLV and satisfy one prediction of the receptor-mediated leukemogenesis hypothesis that T-cell clones identifiable by their T-cell receptor clonotype may be targets for transformation by a particular retrovirus.
Leukemia 1991 Nov
PMID:Radiation leukemia virus-induced T-cell lymphomas with common T-cell receptor variable region structure and similar binding specificity for retrovirus. 196 Oct 32

We performed a genotypic study on lymphoid cells from a patient with adult T-cell leukemia (ATL). Clonal proliferation of human lymphotropic virus type-1(HTLV-1)-infected helper T-cells was detected in the primary skin tumors, while no clonality of the virus-infected lymphocytes was observed in the peripheral blood. Following intensive chemotherapy, however, we detected the presence of two genotypically different HTLV-1-infected lymphocyte clones in different samples taken from the peripheral blood. These data demonstrated the exchange of the dominant neoplastic clone in the clinical course of ATL, suggesting the possibility that a certain clone among many repertoires of HTLV-1-infected T-cells has a capability of leukemogenesis, instead of the primary tumour cells.
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PMID:Exchange of dominant lymphoid cell clones in a patient with adult T-cell leukemia/lymphoma. 196 72

We have cloned and sequenced a cDNA encoding gp34, a novel glycoprotein expressed in cells bearing human T-cell leukemia virus type I (HTLV-I). HTLV-I has a trans-acting transcriptional activator, p40tax, that is thought to be implicated in leukemogenesis through the activation of cellular enhancers. With a subline (JPX-9) of the human T-cell line Jurkat, in which p40tax is inducible, gp34 was shown to be of cellular origin and to be transcriptionally activated by p40tax. It was also demonstrated that two species of mRNA are generated from one copy of the gp34 gene and that these mRNAs encode the identical gp34 product and differ in the 3' untranslated region. Analysis of the deduced amino acid sequence of gp34 showed that it lacks typical signal peptides; however, it has a hydrophobic stretch for membrane anchoring and four possible N-linked glycosylation sites at the carboxy-terminal portion, indicating that it belongs to the family of membrane proteins whose carboxy-terminal portion protrudes out of the cell. The gp34 gene displayed relatively delayed induction compared with other genes activated by p40tax. Taken together with the observation of the dependence of gp34 expression on HTLV-I p40tax, unlike other p40tax-dependent genes such as those for the interleukin-2 receptor alpha chain and c-fos, which are expressed or induced under physiological conditions, we predict that the mechanism involved in the induction of gp34 expression by p40tax is distinct from and more intricate than those for the previously characterized genes.
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PMID:Molecular cloning and characterization of a novel glycoprotein, gp34, that is specifically induced by the human T-cell leukemia virus type I transactivator p40tax. 199 93

We report a mouse model with which to study leukemogenesis initiated by a specific genetic change introduced into a primary lymphoid-myeloid pluripotent stem cell. Fetal liver hemopoietic cells were infected with a high titer of helper-free Abelson murine leukemia virus (A-MuLV) and were used to reconstitute lethally irradiated mice. Two weeks later, progenies of a single primitive hemopoietic stem cell carrying a specifically integrated A-MuLV proviral DNA could be detected in both colony-forming units in spleen and myeloid colony-forming cells in the bone marrow. Beginning at 3 weeks after transplantation, the recipients developed elevated leukocyte counts, splenomegaly, and increase of blast cells in the peripheral blood. Multiple clones of A-MuLV-infected cells were infused into each recipient. However, in the same animal, DNA extracted from various affected organs and from factor-independent lymphoid and myeloid immortalized cells all contained an identical, specifically integrated proviral genome. The A-MuLV-infected stem cells differentiated into various lineages of hemopoietic cells. Our data show that the expression of the v-abl oncogene in a primary lymphoid-myeloid hemopoietic stem cell directly initiates leukemogenesis by stimulating factor-independent growth. The monoclonal-type disease development seen in these animals may require the occurrence of an additional genetic event.
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PMID:Leukemia initiated by hemopoietic stem cells expressing the v-abl oncogene. 199 61

In some cases of acute leukemia an initial potentially leukemogenic genetic alteration can result in clonally derived end-cells normal in appearance and numbers. We refer to this clonal expansion as preleukemia. Subsequent alterations, intrinsic or extrinsic, often referred to as transformation, result in abnormal differentiation and/or growth regulation; we refer to this as leukemia. Several issues are unresolved. Where in the hierarchy of hematopoiesis clonal expansion and transformation occur is unknown. It is quite likely that clonal expansion occurs in cells with considerable self-renewal potential--probably stem or progenitor cells. The precise site may vary in different cases and account for the diverse phenotypes of acute leukemia. How the preleukemia clone comes to dominate hematopoiesis and the fate of the residual normal stem cells and their progeny are also unknown. Likewise, there is controversy whether different models of leukemogenesis operate in different subjects. For example, are older persons or those with occupational exposure to potentially leukomogenic agents more likely to exhibit one pattern of leukomogenesis? Finally, it is unknown whether these diverse models of leukemogenesis respond differently to therapy.
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PMID:Relationship between clonality and transformation in acute leukemia. 199 41

Serum interleukin-2 (IL-2), soluble IL-2 receptors (sIL-2R) and tumor necrosis factor-alfa (TNF-alpha) levels were determined in 66 previously untreated consecutive patients with acute myeloid leukemia (AML) and in 22 normal volunteers. The following mean (+/- SE) values were observed in patients and controls, respectively: 35 +/- 14.7 (range 0.5-500) and 0.7 +/- 0.02 (0.5-0.8 U/ml for IL-2 (p = 0.001); 1622 +/- 289 (110-10,600) and 422 +/- 30 (207-666) U/ml for sIL-2R (p = 0.0001); 1247 +/- 196 (218-4672) and 152 +/- 11 (75-308) pg/ml for TNF-alpha (p = 0.0001). With respect to the FAB classification system, we found a significantly different distribution of serum IL-2 mean values in distinct subcategories, i.e. 3.4 +/- 1.9 U/ml in M1-M2-M3 and 42.4 +/- 20.4 U/ml in M4-M5 subgroups, respectively (p = 0.01), whereas sIL-2R and TNF-alpha levels were 1144 +/- 322 U/ml and 1120 +/- 317 pg/ml in M1-M2-M3 patients and 1945 +/- 317 U/ml and 1270 +/- 259 pg/ml in the M4-M5 group. A significantly positive correlation between TNF-alpha and sIL-2R (r = 0.53; p = 0.002) was also detected in the M4-M5 group. Sixty-three out of 66 patients received an intensive chemotherapy program. Univariate analysis showed that age and sIL-2R greater than 2000 U/ml significantly affected both complete remission rate and overall survival, whereas by multivariate analysis, age was the only independent variable significantly influencing survival. These data confirm recent in vitro evidence suggesting the role of IL-2, sIL-2R, and TNF-alpha in the control of normal hematopoiesis and leukemogenesis. Since the availability of recombinant cytokines for clinical use in AML, it is crucial to understand their spectrum of interaction in order to select the appropriate combination for in vivo administration.
Leukemia 1991 Jan
PMID:Serum interleukin-2 (IL-2), soluble IL-2 receptors and tumor necrosis factor-alfa levels are significantly increased in acute myeloid leukemia patients. 199 55

The gene E2A has recently been cloned, mapped to 19p13 and shown to be rearranged in cases of pre-B acute lymphoblastic leukemia (ALL) with t(1;19) (q23;p13). Nine cases with a 19p13 breakpoint, four having a phenotype other than pre-B, have been investigated with the E12 probe to the E2A gene. Five cases had t(1;19) (q23;p13) and C-ALL with pre-B phenotype in four out of four cases tested. Two cases had t(1;19) (q21;p13), one with Null cell phenotype, t(4;11), and 'jumping translocations' and the other with acute non-lymphocytic leukemia M5 following bone marrow transplantation for C-ALL. Variant translocations in patients with ALL were t(15;19) (q15;p13) and t(17;19) (q21;p13). Southern blotting with E12 showed rearrangement in the cases with t(1;19) (q23;p13) and t(1;19) (q21;p13), but not in other cases with variant 19p13 breakpoints. Thus rearrangement of the E2A gene is not restricted to cases with pre-B ALL but may also occur in acute leukemias with other immunological phenotypes. Failure to detect rearrangement in 19p13 variants may be due to an E2A breakpoint outside the E12 recognition region. Alternatively, there may be further genes in this location with relevance to leukemogenesis.
Leukemia 1991 Jan
PMID:Molecular investigation of 19p13 in standard and variant translocations: the E12 probe recognizes the 19p13 breakpoint in cases with t(1;19) and acute leukemia other than pre-B immunophenotype. 199 56

In a patient with idiopathic myelofibrosis (MFI) that had progressed to acute nonlymphoid leukemia (ANLL) after a long-lasting cytotoxic treatment, we observed two karyotypically independent cell populations, one showing trisomy of chromosome 8 as the only anomaly and one with an unbalanced translocation t(5;17)(q11) resulting in partial monosomy of 5q and 17p. The overall karyotypic configuration suggested that chromosome changes occurred as secondary events during the multistep process of leukemogenesis. The probable sequence of cytogenetic events in this patient and a review of the literature indicated that the t(5;17) may represent a therapy-induced abnormality nonrandomly related to the terminal phase of myeloid disorders.
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PMID:Trisomy 8 and an unbalanced t(5;17)(q11;p11) characterize two karyotypically independent clones in a case of idiopathic myelofibrosis evolving to acute nonlymphoid leukemia. 200 12

T-lymphoma, including adult T-cell leukemia-lymphoma (ATL) accounted for 75% of non-Hodgkin's lymphoma in the Kyushu district of Japan and for 43% in the nation as a whole. Human T-cell leukemia/lymphoma virus type I (HTLV-I) is closely associated with ATL; however, 11 (7.5%) of 147 patients with ATL were HTLV-I negative. The cumulative percentage incidence of anti-HTLV-I seropositive ATL patients can be simply described by a Weibull model of the typical tear-off type, suggesting that ATL leukemogenesis may be the result of accumulation of approximately five critical events, most likely somatic mutations within HTLV-I-infected T-cells. ATL is still a difficult disease to treat successfully, while peripheral non-ATL T-lymphoma responded to standard chemotherapy in the same way as B-lymphoma. The disease entity of immunoblastic lymphadenopathy (IBL)-like T-lymphoma was also described. Morphological recognition of focal or sheetlike proliferation of atypical neoplastic pale cells and immunoblasts of T-cell nature were important findings for the diagnosis. Major prognostic factors differed greatly among ATL, peripheral non-ATL T-lymphoma and B-lymphoma. Pathology was not associated with treatment outcome and survival in T-cell diseases. These results indicate that the terms ATL, peripheral non-ATL T-lymphoma, and B-lymphoma should be used instead of the all-inclusive term non-Hodgkin's lymphoma, because of differences in cellular origin, clinical features, treatment outcome, prognosis, prognostic factors, chromosomal aberrations, and etiology.
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PMID:Peripheral T-cell lymphoma in Japan: recent progress. 204 13


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