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

In the work it has been decided to evaluate the occurrence of locus bcl-1 rearrangement in type B chronic lymphatic leukemia and that of gene bcl-2 in non-Hodgkin's lymphoma with diffuse morphology, as well as in reactive lymph nodes. The study material comprised DNA isolated from fragments of lymph nodes sent for routine diagnostic examinations at the Institute of Pathology--Pomeranian Medical Academy. Southern's method was used to examine DNA having been cut with restrictive enzymes, estimating the distribution of gene bcl-2 and locus bcl-1. Resorting to Polymerase Chain Reaction (PCR) translocation t (14;18) was assessed by means of short nucleotides hybridizing with 14 and 18 chromosome sequences restricting this translocation. The amplification product was subsequently studied by Southern's method with probe bcl-2. In 1 out of 18 examined cases of type B chronic lymphocyte leukemia it was disclosed that locus bcl-1 had been rearranged. In 45 cases of non-Hodgkin's lymphoma with diffuse morphology the gen bcl-2 was found to display germline arrangement. Germline position of gen bcl-2 was also revealed in 60 cases of reactive lymph nodes.
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PMID:[Molecular-genetic evaluation of translocation of bcl-2 gene and locus bcl-1 in selected lymphoproliferative changes]. 129 Mar 53

Recent immunopathologic studies have demonstrated that primary follicles and the mantle zones of secondary follicles are composed largely of virgin B lymphocytes which migrate from the bone marrow to these areas, and are the precursor cells of germinal centers. Non-Hodgkin's lymphomas corresponding to these immature B cells include mantle zone lymphoma (MZL), a primary follicle variant of MZL without reactive germinal centers, and diffuse intermediate lymphocytic (centrocytic) lymphoma. Diffuse intermediate lymphocytic lymphoma (DILL) is considered a late stage in the progression of MZL. Cytologically, these lymphomas usually resemble their normal cellular counterparts and consist predominantly of atypical small lymphoid cells with slightly-irregular and indented nuclei, moderately-coarse chromatin, inconspicuous nucleoli, and scant cytoplasm. Small lymphocytic, cerebriform and blastic variants have also been described. In smears and touch preparations, the neoplastic cells are usually prolymphocytes. Immunologically, the cells have features of virgin B cells, bearing pan-B cell antigens along with monoclonal surface IgM, with or without surface IgD, and CD5 (Leu 1) antigen, and lacking common acute lymphocytic leukemia associated (CALLA) antigen. Cytogenetically, the t(11;14)(q13;q32) has been associated with this group of lymphomas, and expression of the putative cellular oncogene bcl-1 (11q13) has been demonstrated in 30-50% of cases. Clinically, the patients have a median age of 60 years and usually present with advanced stage disease. Splenomegaly, often massive, is present in 80% of those with MZL. Patients with MZL have a significantly longer median survival (74-77 months) than those with DILL (30-33 months), and survival in both groups is significantly prolonged if a complete clinical remission is attained. Based on clinical studies, MZL should be considered a low grade lymphoma and DILL should be considered an intermediate grade lymphoma by Working Formulation criteria. The lymphomas of primary follicle/mantle zone origin are a distinct clinicopathologic entity biologically analogous to the follicular and diffuse lymphomas of germinal center origin, from which they should be distinguished in current and future classifications of non-Hodgkin's lymphoma.
Leukemia 1991
PMID:Non-Hodgkin's lymphomas of primary follicle/mantle zone origin. 171 36

Cytogenetic studies using B-cell mitogens indicate that approximately 50% of patients with chronic B-cell leukemia (CLL) have chromosome abnormalities. The most common abnormality is an additional chromosome 12, either as the sole abnormality or in conjunction with other abnormalities such as 14q+, 6q-, and 11q-. In two instances, the 14q+ is a result of a translocation from either chromosome 11, t(11;14), or chromosome 19, t(14;19). These two translocations led to the identification of the bcl-1 and bcl-3 genes located on chromosomes 11 and 19, respectively. Very few instances of oncogene activation have been described and it does not seem to be an important mechanism in the pathogenesis of CLL. Further cytogenetic and molecular studies may provide clues for the identification of the genes involved in CLL.
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PMID:Cytogenetic and molecular changes in chronic B-cell leukemia. 259 62

We analyzed 50 B cell lymphoma samples by Southern blot analysis, using the bcl-1 and heavy chain immunoglobulin (JH) probes with two or more restriction endonucleases. All samples showed JH rearrangement, and three samples (two diffuse small lymphocytic lymphomas and one diffuse large cell lymphoma probably transformed from a diffuse small lymphocytic lymphoma) demonstrated rearranged bcl-1 sequences. The three samples showed the t(11;14)(q13;q32) chromosome translocation, and all three contained rearranged JH fragments that comigrated with the rearranged bcl-1 fragment. The breakpoint of the translocation occurred within a 1.6-kb region on chromosome 11 in the three cases. Two of the three patients had primary refractory disease. Two of the three patients had gastrointestinal involvement. Bcl-1 rearrangement may identify an unusual subset of patients with primary refractory disease with gastrointestinal involvement. It may also describe a unique subset of large cell lymphoma patients transformed from diffuse small cell histology.
Leukemia 1988 Jun
PMID:Bcl-1 gene rearrangements in B cell lymphoma. 325 59

Oncogenes, in the context of retroviruses, are a common cause of leukemia in animals. Recently, activation of cellular oncogenes has been shown to be associated with leukemia in humans. Relatively few studies of oncogene activation in chronic lymphocytic leukemia (CLL) have been reported. In most instances, rearrangement of oncogenes has not been detected. Exceptions include the bcl-1 oncogene in B-cell prolymphocytic leukemia, the tcl-1 oncogene in T-cell CLL, the Hu-ets-1 and Hu-ets-2 oncogenes in small cell lymphocytic lymphoma and c-myc in a Sezary cell leukemia cell/line. Overall, it appears that oncogene abnormalities are less common in CLL than in other leukemias. The reason for it is uncertain and may relate to the relatively few cases evaluated. Alternatively, novel mechanisms of oncogene involvement or gene other than oncogenes may be important in the etiology or pathogenesis of CLL.
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PMID:Oncogenes in chronic lymphocytic leukemia. 328 28

Cyclin D1/PRAD1 (bcl-1) is a recently discovered proto-oncogene that is overexpressed in mantle cell lymphomas and several other human tumors. In a previous study, the authors demonstrated expression of cyclin D1 in 15 of 15 cases of mantle cell lymphoma and 1 of 8 cases of B-chronic lymphocytic leukemia (B-CLL) using a polyclonal antibody and microwave enhanced immunohistochemical staining method on paraffin-embedded tissue sections. In this study, 107 additional B- and T-cell neoplasms were studied, including 47 cases of high grade lymphoma (33 diffuse large B-cell type, 9 Burkitt and Burkitt-like, 4 precursor T-lymphoblastic lymphoma, and 1 adult T-cell lymphoma/leukemia), 38 additional cases of low grade B-cell lymphoma (18 CLL, 15 hairy cell leukemia and 5 mantle cell lymphoma), and 22 plasmacytomas for expression of cyclin D1 using the same immunohistochemical staining technique. All cases of mantle cell lymphoma showed diffuse nuclear staining. No additional cases of CLL showed cyclin D1 expression. In contrast, 1 of 15 hairy cell leukemias and 1 of 22 plasmacytomas showed cyclin D1 staining. None of the high grade lymphomas demonstrated expression of cyclin D1 protein by immunostaining, including three cases of large B-cell lymphoma that coexpressed CD5. The authors conclude that cyclin D1 is expressed in all cases of mantle cell lymphoma, and only in very rare cases of B-CLL, hairy cell leukemia and plasmacytoma/myeloma. Cyclin D1 does not appear to play an important role in high grade lymphomas. In addition, most CD5 positive high grade B-cell lymphomas do not express cyclin D1, and are not likely to be derived from mantle cell lymphoma or other lymphomas with t(11;14).
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PMID:Cyclin D1 expression in non-Hodgkin's lymphomas. Detection by immunohistochemistry. 754 Mar 62

The p27Kip1 gene codes for a cyclin-dependent kinase inhibitor implicated in G1 arrest by transforming growth factor beta, cell-cell contact, agents that elevate cyclic AMP, and the growth-inhibitory drug rapamycin. p27 binds to and inhibits complexes formed by cyclin E-cdk2, cyclin A-cdk2, and cyclin D-cdk4. The involvement of p27 in the negative regulation of cell proliferation suggests that it may also function as a tumor suppressor gene. Using a combination of somatic cell hybrid panels and fluorescence in situ hybridization p27Kip1 has been mapped to the short arm of chromosome 12 at the 12p12-12p13.1 boundary, reported to harbor deletions and rearrangements in leukemia and mesotheliomas. In order to assess potential p27Kip1 gene alterations, we have screened a total of 147 human primary solid tumors and found no detectable cancer-specific mutations. These results argue that the often observed loss of antimitogenic transforming growth factor beta responsiveness in human cancer cells is not due to structural defects in p27Kip1.
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PMID:p27Kip1: chromosomal mapping to 12p12-12p13.1 and absence of mutations in human tumors. 788 10

A phenotypic and molecular evaluation was made of 15 patients with mature B-cell leukemia/lymphoma showing exclusive spleen and bone marrow involvement. According to French-American-British criteria, these cases could not be classified as classical B-cell chronic lymphocytic leukemia, hairy cell leukemia and its variant forms, splenic lymphoma with villous lymphocytes, or leukemic phase non-Hodgkin's lymphoma (NHL; follicular or intermediate type). The immunophenotype pattern (high surface Ig and CD25 expression, and little or no reactivity with CD5, CD23, and CD11c) and cytomorphologic features of these neoplasms suggested an origin in the marginal zone of the spleen. Molecular analysis did not show any involvement of the dominantly acting oncogenes generally associated with lymphoid malignancies (c-myc, bcl-2, bcl-1, Ras), but mutations of the p53 tumor suppressor gene involving exons 5, 6, and 8 were found in 6 cases (6 of 15, 40%). In 4 cases, the p53 alterations consisted of a point mutation leading to amino acid substitution. In the remaining 2 cases, an insertion or deletion resulting in a frame-shift of the protein was observed. In all but 1 of the cases, the wild-type sequence at the mutation site was barely visible, implying the loss of the normal p53 allele in leukemic cells. All of the cases showed a clinical course compatible with that of low-grade NHL, regardless of the p53 loss/mutation. Overall, our data suggest the existence of a form of splenic B-cell leukemia/lymphoma of possible marginal zone origin in which p53 inactivation may play an important pathogenetic role.
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PMID:Frequent p53 gene involvement in splenic B-cell leukemia/lymphomas of possible marginal zone origin. 801 22

The 11q13 breakpoint region of t(11;14) (q13;q32), translocated to the Ig heavy chain locus at 14q32, has been designated as BCL-1 for B-cell leukemia/lymphoma-1, but the nature of the transcriptional unit has long remained unclear. Recently, the PRAD1 gene encoding cyclin D1, isolated from the 11q13 region, was proposed as a candidate BCL-1 gene on the basis of chromosome walking and concordant overexpression of PRAD1 mRNA in cell lines with t(11;14)(q13;q32). We report here molecular analysis of a variant translocation at the BCL-1 locus, t(11;22)(q13;q11), showing juxtaposition of the Ig light chain gene, Ig lambda, to the PRAD1 gene at its 3' end, resulting in overexpression of PRAD1 mRNA. Because only the PRAD1 gene is present between the Ig heavy chain and light chain gene breakpoints, an identity between BCL-1 and the PRAD1/cyclin D1 gene is strongly indicated.
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PMID:A variant chromosome translocation at 11q13 identifying PRAD1/cyclin D1 as the BCL-1 gene. 804 38

Chromosome 11q13 translocation breakpoints have been found dispersed over more than 100 kb of genomic DNA in centrocytic lymphoma and lymphocytic lymphoma of intermediate differentiation (mantle cell lymphoma). Approximately one-half of these translocations occur at the bcl-1 major translocation cluster (MTC) and appear tightly clustered by Southern blot restriction mapping. In order to specifically characterize these t(11;14)(q13;q32) translocations, six cases of centrocytic lymphoma with MTC rearrangements on Southern blot were studied. Genomic DNA was amplified by PCR (polymerase chain reaction) using a consensus immunoglobulin heavy-chain joining gene (JH) primer and two separate MTC primers. Sequencing of the PCR products revealed the MTC breakpoints in all six cases to be clustered within a 61 basepair span, very similar to those previously reported in t(11;14)-containing human B-cell lines. No two breakpoints were identical. JH breakpoints involved JH4 in five cases and JH6 in the other. Tight clustering of the MTC breakpoints thus permits PCR detection of the t(11;14) in many cases of centrocytic lymphoma, which may be of value in classifying this subtype of non-Hodgkin's lymphoma.
Leukemia 1993 Sep
PMID:Chromosome t(11;14)(q13;q32) breakpoints in centrocytic lymphoma are highly localized at the bcl-1 major translocation cluster. 837 93


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