Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alterations of onco/tumour suppressor genes are involved in the formation of human hematological malignancies. Previously, in animal models, we demonstrated the applicability of in vivo gene expression investigations to monitor the effects of certain carcinogenic chemicals. In our present study we determined the expression of onco/suppressor genes from isolated peripheral white blood cells of patients with chronic myeloid leukaemia (CLL) and non-Hodgkin lymphoma (NHL). Gene expressions were determined by isolation of total RNA and slot blot hybridization with chemiluminescently labeled gene probes (Ha-ras, c-myc and p53) Expression levels were compared before and after treatment with a combined cytostatic protocol, containing cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP). Both the CLL and NHL group of patients exhibited significantly higher expression of the investigated genes than healthy controls. One month after the cytostatic treatment, we found considerably fewer individuals with overexpressed oncogenes than before the treatment. Our study proved that onco/tumour suppressor gene expressions could be used as biomarkers of certain hematological malignancies, and to monitor the therapeutical effect of cytostatic drugs.
 ...
PMID:The usefulness of in vivo gene expression investigations from peripheral white blood cells: a preliminary study. 1049 9

Small amounts of free DNA circulate in both healthy and diseased human plasma/serum, and increased concentrations of DNA are present in the plasma of cancer patients. Characteristics of tumour DNA have been found in genetic material extracted from the plasma of cancer patients. These features include decreased strand stability and the presence of specific oncogene, tumour suppressor gene and microsatellite alterations. Point mutations of the ras genes have been detected in the plasma DNA of patients suffering from haematopoetic malignancies, colorectal and pancreatic cancer, sometimes prior to clinical diagnosis. Rearranged immunoglobulin heavy chain DNA has been found in the plasma of patients with non-Hodgkins lymphoma and acute B cell leukaemia. Microsatellite instability, expressed either as a new allele or a loss of one allele (LOH) occurs in the plasma and serum DNA of patients suffering from head and neck, lung and renal cell cancer. The results obtained in many different cancers have opened a new research area indicating that plasma DNA might eventually be a suitable target for the development of non-invasive diagnostic, prognostic and follow-up tests for cancer.
 ...
PMID:Detection of circulating tumour DNA in the blood (plasma/serum) of cancer patients. 1050 46

X-linked lymphoproliferative disease (XLP) is a primary immunodeficiency, which most often manifests itself after Epstein-Barr virus (EBV) infection. The main clinical phenotypes include fulminant or fatal infectious mononucleosis, dysgammaglobulinaemia and malignant lymphoma. We have recently cloned the SH2D1A gene, which has been shown to be mutated in approximately 70% of XLP patients. Now we report five novel SH2D1A mutations in patients from five unrelated XLP families. No mutations were found in another three XLP families. In three boys with early onset non-Hodgkin lymphoma (NHL) from two unrelated families a deletion of SH2D1A exon 1 and a splice site mutation were found, respectively. These patients did not show any laboratory or clinical signs of a previous EBV infection. A fourth EBV-uninfected and unrelated boy with a stop mutation in the SH2D1A gene shows only signs of dysgammaglobulinaemia. Development of dysgamma-globulinaemia and lymphoma without evidence of prior EBV infection in four of our patients suggests that EBV is unrelated to these phenotypes, in contrast to fulminant or fatal infectious mononucleosis. The role of SH2D1A as a putative tumour suppressor gene remains to be investigated.
 ...
PMID:Epstein-Barr virus-negative boys with non-Hodgkin lymphoma are mutated in the SH2D1A gene, as are patients with X-linked lymphoproliferative disease (XLP). 1055 88

Specific defects in DNA repair pathways are reflected by DNA microsatellite instability (MSI) and play an important role in carcinogenesis. Reported frequencies in gastric non-Hodgkin's lymphomas (NHL) vary from 14% to as high as 90%. Another form of genetic instability in tumours is allelic imbalance (AI) due to loss or gain of genetic material at a specific chromosomal region. This might point to the presence of a tumour suppressor gene or oncogene. We examined both MSI and AI in 26 gastric lymphomas (10 low-grade and 13 high-grade MALT lymphomas and three cases lacking MALT features and categorised as diffuse large B cell lymphoma (DLCL)). Tumour components and normal cells (epithelium, muscle) were microdissected from paraffin-embedded resection samples. Contrary to other studies we did not observe frequent MSI when investigating 18 different loci distributed over 12 chromosomes. Microsatellite instability of a single locus was found in 1/10 (10%) low-grade MALT lymphomas and 2/13 (15%) high-grade MALT lymphomas. These data indicate that DNA mismatch repair genes do not play a role in the pathogenesis of these lymphomas. Allelic imbalance was detected in 60% (6/10) of low-grade MALT lymphomas, in 62% (8/13) of high-grade MALT lymphoma and in 67% (2/3) of DLCL. In high-grade lymphomas more loci showed AI (one to seven loci, with a mean of 2.5 loci per case) than in the low-grade lymphomas (one to two loci, with a mean of 1.3 loci per case), possibly reflecting an increased genomic instability.
 ...
PMID:Frequent allelic imbalance but infrequent microsatellite instability in gastric lymphoma. 1055 55

The aim was to investigate the combined immunoexpression of p53, p21, bcl-2, bax, Rb and Ki67 proteins in Hodgkin's lymphomas (HL) and correlate expression patterns with the histotype and the Epstein-Barr Virus (EBV) status. Paraffin-sections from 56 cases of HL (18 nodular sclerosis and 38 mixed cellularity) and from ten "reactive" lymph nodes were investigated. P53, p21, bcl-2, bax, Rb and Ki67 proteins were detected in Hodgkin and Reed-Sternberg (HRS) cells in 35/56, 56/56, 24/56, 23/56, 56/56 and 56/56 cases of HL, respectively. No correlation was found between the expression of each protein and the EBV status or the histotype of HL. Comparison between p53 and p21 staining revealed two patterns: a) p53+/p21+ (35 cases); and b) p53-/p21+ (21 cases). The pattern p53+/p21+ suggests wild type p53 protein able to induce the expression of p21 while the p53-/p21+ pattern suggests p53-independent p21 expression. These results are consistent with the interpretation that inactivating p53 gene mutations may be rare in HL. Comparison between bcl-2 and bax staining showed a statistically significant relationship (p<0.001) for coexpression (19 cases) or absence of expression of both proteins (28 cases) in HRS cells. In contrast, bax expression was observed in most lymphoid cells in all "reactive" lymph nodes. Since the proapoptotic bax protein may act as tumour suppressor it is possible that the absence of this protein in HRS cells in a substantial proportion of HL may confer growth advantage and play a role in their pathogenesis. This could suggest bax gene alterations in some HL since in other studies acute lymphoblastic leukaemia cell lines demonstrate bax gene mutations with loss of bax immunoexpression. Another possibility is that reduced bax expression may be due to post transcriptional regulation, as was described in lymphoma cell lines. Comparison between Rb and Ki67 staining disclosed two main deviations from the normal parallel relationship in reactive lymph nodes: a) 2 cases with low Rb and high Ki67 expression possibly reflecting loss of Rb expression due to chromosome loss or to other abnormalities in the structure or the expression of Rb gene; and b) 9 cases with high RB and low Ki67 possible reflecting an attempt of Rb protein in excess to induce cell cycle arrest. Taken together, our findings provide combined immunohistological evidence for deregulated expression of cell-cycle and apoptosis-related proteins, that may play a role in the pathogenesis of HL.
 ...
PMID:Expression of p53, p21/waf1, bcl-2, bax, Rb and Ki67 proteins in Hodgkin's lymphomas. 1080 63

Ataxia telangiectasia (AT) is a rare multisystem, autosomal, recessive disease characterised by neuronal degeneration, genome instability, and an increased risk of cancer. Approximately 10% of AT homozygotes develop cancer, mostly of the lymphoid system. Lymphoid malignancies in patients with AT are of both B cell and T cell origin, and include Hodgkin's lymphoma, non-Hodgkin's lymphoma, and several forms of leukaemia. The AT locus was mapped to the chromosomal region 11q22-23 using genetic linkage analysis in the late 1980s and the causative gene was identified by positional cloning several years later. The ATM gene encodes a large protein that belongs to a family of kinases possessing a highly conserved C-terminal kinase domain related to the phosphatidylinositol 3-kinase domain. Members of this kinase family have been shown to function in DNA repair and cell cycle checkpoint control following DNA damage. Recent studies indicate that ATM is activated primarily in response to double strand breaks and may be considered a caretaker of the genome. Most mutations in ATM result in truncation and destabilisation of the protein, but certain missense and splicing errors have been shown to produce a less severe phenotype. AT heterozygotes have a slightly increased risk of breast cancer. Atm deficient mice exhibit many of the symptoms found in patients with AT and have a high frequency of thymic lymphoma. The association between mutation of the ATM gene and a high incidence of lymphoid malignancy in patients with AT, together with the development of lymphoma in Atm deficient mice, supports the proposal that inactivation of the ATM gene may be of importance in the pathogenesis of sporadic lymphoid malignancy. Loss of heterozygosity at 11q22-23 (the location of the ATM gene) is a common event in lymphoid malignancy. Frequent inactivating mutations of the ATM gene have been reported in patients with rare sporadic T cell prolymphocytic leukaemia (T-PLL), B cell chronic lymphocytic leukaemia (B-CLL), and most recently, mantle cell lymphoma (MCL). In contrast to the ATM mutation pattern in AT, the most frequent nucleotide changes in these sporadic lymphoid malignancies were missense mutations. The presence of inactivating mutations, together with the deletion of the normal copy of the ATM gene in some patients with T-PLL, B-CLL, and MCL, establishes somatic inactivation of the ATM gene in the pathogenesis of lymphoid malignancies, and strongly suggests that ATM functions as a tumour suppressor. The presence of missense mutations in the germline of patients with B-CLL has been reported, suggesting that some patients with B-CLL may be constitutional AT heterozygotes. The putative hereditary predisposition of B-CLL, although intriguing, warrants further investigation.
 ...
PMID:Ataxia telangiectasia gene mutations in leukaemia and lymphoma. 1142 21

BCL10 is a tumour suppressor gene originally cloned from a t(1;14)(p22;q32) breakpoint in a case of mucosa-associated lymphoid tissue (MALT) lymphoma. Translocations involving this gene, though uncommon, are sometimes encountered in MALT lymphomas. This gene is thought to play an important role in the development of malignant lymphomas. Fluorescence in situ hybridization (FISH) was therefore undertaken on 22 cases of malignant lymphoma of varying histology to establish the incidence of rearrangements involving the BCL10 gene. Initially, one case with a novel t(1;2)(p22;p12) translocation involving the BCL10 gene was identified, in a marginal zone lymphoma of the MALT type, and was reported elsewhere. Seven other cases were subsequently identified with abnormalities in the 1p region, including a translocation with a breakpoint in the 1p22 region in a case of lymphoblastic lymphoma. However, none of these involved the BCL10 gene. Mutation analysis of BCL10 was then performed on 57 cases of malignant lymphoma, including 17 MALT lymphomas, by single-strand conformational polymorphism (SSCP) analysis of tumour DNA. Tissue was obtained for mutation analysis for 12 of the 22 cases analysed by FISH. Selected cases with SSCP band shifts were further studied by direct sequencing. Polymorphisms were identified in eight cases, but no mutations of pathogenic significance were identified. Further RT-PCR and mutation analysis was performed on cDNAs from 12 cases (four MALT, seven diffuse large B-cell lymphoma, one Hodgkin's disease) in which DNA analysis had already been completed. This included the MALT lymphoma with the t(1;2)(p22;p12) rearrangement. Again, no mutations were identified in the coding sequence. This study confirms that rearrangements of the BCL10 gene are uncommon in lymphoma (1/22) and may be limited tothe MALT subtype of non-Hodgkin's lymphomas. It was also found that breakpoints or rearrangements in the 1p22 region do not necessarily involve the BCL10 gene. Moreover, the absence of mutations at both the DNA (0/60) and the mRNA (0/12) level indicates that this gene is not frequently inactivated by mutation, in those tumours in which it is not involved in translocations. Our findings suggest that the BCL10 gene is unlikely to have a frequent or key role in general lymphomagenesis.
 ...
PMID:BCL10 in malignant lymphomas--an evaluation using fluorescence in situ hybridization. 1174 43

Although the prognosis of Hodgkin's disease is relatively good, around 20% of patients do not benefit from current therapies and succumb to their disease. A large-scale molecular characterization of disease might help improve HD management. Using cDNA arrays, we studied the mRNA expression levels of approximately 1000 selected genes in 34 benign and malignant lymphoid samples including 21 classical Hodgkin's disease (HD) tissue samples. Hierarchical clustering identified three main molecular groups of HD tumours relevant with respect to histology and clinical outcome (response to therapy and survival). Samples from all bad outcome HD (BOHD) patients clustered in one group whereas the two other groups contained most good outcome HD (GOHD) cases. The nodular sclerosis GOHD samples overexpressed genes involved in apoptotic induction and cell signalling, including cytokines, while the BOHD samples were characterized by the upregulation of genes involved in fibroblast activation, angiogenesis, extracellular matrix remodelling, cell proliferation, and the downregulation of tumour suppressor genes. Our results establish a molecular taxonomy of HD correlating with response to therapy and clinical outcome, thereby suggesting the possibility of improving the current prognostic classification.
 ...
PMID:Gene expression profiling defines molecular subtypes of classical Hodgkin's disease. 1208 42

Patients with relapsing Hodgkin's lymphoma (HL) have a rather poor prognosis and mechanisms that lead to resistance to therapy are poorly understood. Our aims were to investigate the immunohistochemical staining patterns of Rb (retinoblastoma protein) and the p53 tumour suppressor protein in HL at initial presentation and at relapse in order to elucidate a possible role in disease progression and resistance to therapy. Further to evaluate the presence and prognostic importance of Epstein-Barr virus (EBV) and anaplastic lymphoma kinase (ALK). Eighty-one cases of relapsing HL were reexamined histopathologically and immunostained for the expression of p53, Rb, ALK and CD30. EBV was detected with LMP-1 stainings and in situ hybridisation for EBER. Clinical data were extracted from the Swedish National Health Care Programme for HL. Median follow-up time was six years (range 0-12) from the date of relapse. The majority of cases were positive for p53 and Rb both at presentation and at relapse, though to a different extent. Both an increase and a decrease in the proportion of stained tumour cells were observed. None of our cases was ALK-positive and 44% were EBV-positive. No specific staining pattern was directly correlated to survival. In 12 patients a switch in HL subtype from diagnosis to relapse was observed and the five-year Hodgkin-specific survival (HLS) was statistically significantly inferior, 37 vs 81% (p = 0.002), in those patients. We found a significant relation between the expression of p53 and EBV at diagnosis and relapse, indicating a clonal relationship. We were unable to find any specific staining pattern of p53 or Rb, affecting survival.
 ...
PMID:Relapsed Hodgkin's lymphoma: immunostaining patterns in relation to survival. 1215 93

Aberrant promoter hypermethylation is a mechanism of tumour suppressor gene inactivation. We explored aberrant promoter hypermethylation of multiple genes in 88 human immunodeficiency virus (HIV)-non Hodgkin lymphomas (NHL), 25 post-transplant lymphoproliferative disorders (PTLD) and five common variable immunodeficiency (CVI)-related NHL. Twenty-six of 79 (32.9%) HIV-NHL, eight of 14 (57.1%) PTLD and two of five (40.0%) CVI-NHL showed aberrant hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT). Aberrant hypermethylation of death-associated protein-kinase (DAP-K) occurred in 70 of 84 (83.3%) HIV-NHL, 19 of 25 (72.0%) PTLD and three of five (60.0%) CVI-NHL. These data implicate MGMT and DAP-K hypermethylation in lymphomagenesis of immunodeficient hosts. In particular, promoter hypermethylation of DAP-K represents the most frequent molecular alteration yet identified in immunodeficiency-related lymphomas.
 ...
PMID:Frequent aberrant promoter hypermethylation of O6-methylguanine-DNA methyltransferase and death-associated protein kinase genes in immunodeficiency-related lymphomas. 1461 9


<< Previous 1 2 3 Next >>