Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q06643 (non-Hodgkin's lymphoma)
 11,307 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inactivation of the cyclin-dependent kinase inhibitors p16INK4A and p15INK4B are frequent alterations in neoplasia, often resulting from homozygous deletion or promoter region hypermethylation. We have analyzed both modes of inactivation of p15INK4B and p16INK4A in the major types of adult and pediatric hematological malignancies. Hypermethylation of p15INK4B, without alteration of p16INK4A, was an almost universal finding in adult acute myelogenous leukemia, and occurred very frequently in adult acute lymphocytic leukemia and pediatric acute myelogenous leukemia and acute lymphocytic leukemia. In contrast, neither p15INK4B nor p16INK4A were inactivated in any stage of chronic myelogenous leukemia. Hypermethylation of p16INK4A, often without alterations of p15INK4B, was found in non-Hodgkin's lymphoma and was much more frequent in cases with high-grade than low-grade histology. Enriched normal bone marrow stem cells had no detectable promoter region methylation of these genes, as analyzed by a newly developed PCR method. Remarkably distinct patterns of inactivation of p15INK4B and p16INK4A characterize different types of hematological malignancy, and alterations in these tumor suppressor genes are one of the most common alterations in hematological malignancies.
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PMID:Distinct patterns of inactivation of p15INK4B and p16INK4A characterize the major types of hematological malignancies. 904 Nov 82

The novel human pre-B cell line OZ was established from a patient with an aggressive form of non-Hodgkin's lymphoma. Karyotypic analysis of both the primary tumour and OZ cells revealed several marker chromosomes, including the t(14;18)(q32;q21) translocation, which involves the Bcl-2 gene, and alterations on chromosome 17p. Southern blot analysis found identical rearrangements in the 5' region of Bcl-2 gene in the primary tumour and OZ cells. Homozygous deletions of the p15INK4B and p16INK4A genes, however, were present only in OZ cells. Western blot analysis detected aberrant small molecular-weight p53 proteins in both cell types. In addition, OZ cells no longer expressed the CD20 antigen. These findings suggest that Bcl-2 gene rearrangement and aberrant p53 expression resulted in the original B-cell tumour. A subsequent transforming event involving the p15INK4B and p16INK4A genes may have generated more immature cells with a growth advantage during in vitro culture. The genetic alterations involving p53, p15INK4B, and p16INK4A may be implicated in the aggressive form of t(14;18)(q32;q21)-bearing tumours and their poor prognosis.
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PMID:Establishment of a novel human B-cell line (OZ) with t(14;18)(q32;q21) and aberrant p53 expression was associated with the homozygous deletions of p15INK4B and p16INK4A genes. 960 Jan 10

The CDKN2A gene located on chromosome region 9p21 encodes the cyclin-dependent kinase-4 inhibitor p16/INK4A, a negative cell cycle regulator. We analyzed p16/INK4A expression in different types of non-Hodgkin's lymphoma to determine whether the absence of this protein is involved in lymphomagenesis, while also trying to characterize the genetic events underlying this p16/INK4A loss. To this end, we investigated the levels of p16/INK4A protein using immunohistochemical techniques in 153 cases of non-Hodgkin's lymphoma, using as reference the levels found in reactive lymphoid tissue. The existence of gene mutation, CpG island methylation, and allelic loss were investigated in a subset of 26 cases, using single-strand conformational polymorphism and direct sequencing, Southern Blot, polymerase chain reaction, and microsatellite analysis, respectively. Loss of p16/INK4A expression was detected in 41 of the 112 non-Hodgkin's lymphomas studied (37%), all of which corresponded to high-grade tumors. This loss of p16/INK4A was found more frequently in cases showing tumor progression from mucosa-associated lymphoid tissue low-grade lymphomas (31 of 37) or follicular lymphomas (4 of 4) into diffuse large B-cell lymphomas. Analysis of the status of the p16/INK4A gene showed different genetic alterations (methylation of the 5'-CpG island of the p16/INK4A gene, 6 of 23 cases; allelic loss at 9p21, 3 of 16 cases; and nonsense mutation, 1 of 26 cases). In all cases, these events were associated with loss of the p16/INK4A protein. No case that preserved protein expression contained any genetic change. Our results demonstrate that p16/INK4A loss of expression contributes to tumor progression in lymphomas. The most frequent genetic alterations found were 5'-CpG island methylation and allelic loss.
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PMID:Loss of p16/INK4A protein expression in non-Hodgkin's lymphomas is a frequent finding associated with tumor progression. 973 37

Human cancers frequently sustain genetic mutations that alter the function of their G1 cell cycle control check point. These include changes to the retinoblastoma gene and to the genes that regulate its phosphorylation, such as the cyclin-dependent kinase inhibitor p16INK4a. Altered expression of retinoblastoma protein (pRb) is associated with non-Hodgkin's lymphoma, particularly centroblastic and Burkitt's lymphomas. pRb is expressed in normal B-cells and its regulatory phosphorylation pathway is activated in response to a variety of stimuli. Since human B-lymphoma-derived cell lines are often used as in vitro model systems to analyse the downstream effects of signal transduction, we examined the functional status of pRb in a panel of human B-cell lines. We identified eleven cell lines which express the hyperphosphorylated forms of pRb. Furthermore, we suggest that the pRb protein appears to be functional in these cell lines.
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PMID:Loss of functional pRB is not a ubiquitous feature of B-cell malignancies. 1036 Jun 42

The INK4a/ARF locus at chromosome 9p21 encodes two structurally and functionally distinct molecules with tumor-suppressive properties. p16INK4a controls cell cycle progression by inhibiting phosphorylation of the retinoblastoma protein (Rb), while ARF prevents MDM2-mediated degradation of p53. By using a panel of PCR-based methods, we have examined the status of the p16INK4a, ARF and p53 genes in 123 cases of non-Hodgkin's lymphoma (NHL) at diagnosis. Alterations of one or more of these genes were detected in seven of 36 (19%) cases with low- to intermediate-grade histology, and in 35 of 87 (40%) cases with aggressive histology. For the aggressive lymphomas, the Kaplan-Meier estimate of overall survival for cases with disruption of either p16INK4a or the ARF-p53 pathway was not different from cases with retention of both pathways (5 year survival 45% vs 35%; P= 0.85), suggesting that selective inactivation of one of the pathways does not significantly influence overall survival. By contrast, the 5-year survival was only 7% for cases with concurrent disruption of p16INK4a and the ARF-p53 pathway vs 38% for cases with retention of one or both pathways (P = 0.005). Similar results were obtained when the analysis was confined to diffuse large B cell lymphomas (P= 0.019). On stepwise multivariate regression analysis including factors from the international prognostic index, concurrent disruption of p16INK4a and the ARF-p53 pathway was an independent negative prognostic factor in NHL with aggressive histology (P = 0.006). Our results suggest that the compound status of the p16INK4a and ARF-p53 pathways is a major determinant of outcome in NHL.
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PMID:Concurrent disruption of p16INK4a and the ARF-p53 pathway predicts poor prognosis in aggressive non-Hodgkin's lymphoma. 1102 47

Primary mediastinal B-cell lymphoma (PMBL) is a distinct clinical entity among non-Hodgkin's lymphoma. The malignancy has received little attention from a standpoint of basic research due in part to its rarity. However, based on recent studies consistent trends are beginning to emerge regarding the molecular and chromosomal alterations commonly observed in this disease. By both CGH and AP-PCR, genetic gains involving chromosomes 2, 5, 7, 9p, 12, and Xq are among the most frequently observed events. From a molecular standpoint, alterations in the c-myc, p16(INK4) and p53 genes have been observed in up to 30% of cases. This information along with the well-established histological, immunological, and clinical features should convince the few remaining disbelievers that PMBL is a distinct pathological entity among non-Hodgkin's lymphomas.
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PMID:Genetic alterations in primary mediastinal B-cell lymphoma: an update. 1134 56

Cancer is also an epigenetic disease. The main epigenetic modification in humans is DNA methylation. Transformed cells undergo a dramatic change in their DNA methylation patterns: certain CpG islands located in the promoter regions of tumor-suppressor genes become hypermethylated and the contiguous gene rests silenced and this phenomenon occurs in an overall genomic environment of DNA hypomethylation. The profile of CpG island hypermethylation in hematologic malignancies is an epigenetic signature unique for each subtype of leukemia or lymphoma. Although the most widely studied genes are the cell-cycle inhibitors p15INK4b and p16INK4a (specially in AML and ALL), the list of methylation-repressed genes in these neoplasms is expanding very rapidly, including MGMT, RARB2, CRBP1, SOCS-1, CDH1, DAPK1, and others. A necessary cross-talk between genetic alterations and DNA methylation exists: certain chromosomal translocations may induce hypermethylation, such as the PML-RARa, or attract methylation, such as BCR-ABL, but DNA hypomethylation can be the culprit behind the genesis of certain abnormal recombination events. From a translational standpoint, hypermethylation can be used as a marker of recurrent disease or progression, for example, in MDS, or response to chemotherapy, such as MGMT methylation in B-cell non-Hodgkin's lymphoma. Furthermore, promising studies using DNA demethylating agents and histone deacetylase inhibitors are underway to awake these dormant tumor-suppressor genes for a better treatment of the patient with a hematologic malignancy.
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PMID:Profiling aberrant DNA methylation in hematologic neoplasms: a view from the tip of the iceberg. 1458 79

Primary effusion lymphoma (PEL) is very rare type of non-Hodgkin's lymphoma (NHL) usually confined to the body cavities such as the pleural space, pericardium, and peritoneum. PEL is a human herpes virus-8 (HHV-8)-associated lymphoma and commonly observed in human immunodeficiency virus (HIV)-infected patients. However, HIV-infected patients are extremely fewer in Japan in comparison with those in Western countries; PEL is usually not associated with HIV infection in Japan. This report presents seven Japanese cases of PEL. In situ hybridization revealed that the PEL cells were negative for EBV in all cases. An immunocytological analysis showed that only one case was positive for HHV-8, and PEL cells were positive for CD20 in all cases. MUM1 was positive, but CD10 and CD138 were negative in six cases. One case each was positive for CD30 and BCL-6. The phenotypic patterns of HIV-related is BCL6-/MUM1+/CD138+, thus, the phenotypic findings observed by immunocytochemistry in this study were somehow different from those reported in Western countries. However, the cytomorphological features of PEL cells showed large cell size, abundant basophilic cytoplasm, coarse chromatin, and occasional binucleated or multinucleated cells, similar to a large cell immunoblastic and anaplastic large cell lymphoma, indicating that the cytomorphological characteristics of PE cells in Giemsa and Papanicolaou stain were consistent with those reported abroad. The prognosis for PEL in these cases was poor, but the survival time was variable ranging from 1 month to 54 months, and was different from that of Western cases. No p16/CDKN2A expression was observed, and one case showed PEL cells with a BLIMP1 mutation.
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PMID:Cytologic and immunocytochemical features of EBV negative primary effusion lymphoma: report on seven Japanese cases. 1921 41