Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P04637 (p53)
77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

B-cell chronic lymphocytic leukemia (B-CLL) results in an accumulation of mature CD5(+)/CD23(+) B cells due to an uncharacterized defect in apoptotic cell death. B-CLL is not characterized by a unique recurrent genomic alteration but rather by genomic instability giving rise frequently to several chromosomal aberrations. Besides we reported that approximately 15% of B-CLL patients present malignant B-cells resistant to irradiation-induced apoptosis, contrary to approximately 85% of patients and normal human lymphocytes. Telomere length shortening is observed in radioresistant B-CLL cells. Using fluorescence in situ hybridization (FISH) and multicolour FISH, we tested whether specific chromosomal aberrations might be associated with the radioresistance of a subset of B-CLL cells and whether they are correlated with telomere shortening. In a cohort of 30 B-CLL patients, all of the radioresistant B-CLL cell samples exhibited homozygous or heterozygous deletion of 13q14.3 in contrast to 52% of the radiosensitive samples. In addition to the 13q14.3 deletion, ten out of the 11 radioresistant B-cell samples had another clonal genomic alteration such as trisomy 12, deletion 17p13.1, mutation of the p53 gene or translocations in contrast to only three out of 19 radiosensitive samples. Telomere fusions and non-reciprocal translocations, hallmarks of telomere dysfunction, are not increased in radioresistant B-CLL cells. These findings suggest (i) that the 13q14.3 deletion accompanied by another chromosomal aberration is associated with radioresistance of B-CLL cells and (ii) that telomere shortening is not causative of increased clonal chromosomal aberrations in radioresistant B-CLL cells.
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PMID:Increased genomic alteration complexity and telomere shortening in B-CLL cells resistant to radiation-induced apoptosis. 1918 4

This study was aimed to investigate the significance of interphase fluorescence in situ hybridization (FISH) in detecting +12, del (13q14), p53 and atm gene deletion in chronic lymphocytic leukemia (CLL). FISH and a panel of probes (CEP 12, LSI D13S319, LSI p53, LSI atm) were used to detect molecular cytogenetic abnormalities in 30 patients with CLL. Cytogenetic aberrations and their relation with some other prognostic factors (peripheral lymphocyte count, Binet stage, LDH level, ZAP-70 and so on) were analyzed. The results indicated that out of the 30 CLL patients, molecular cytogenetic aberrations were found in 19 (63.3%) cases and 7 (23.3%) patients showed more than two kinds of abnormalities. The most frequent abnormality detected was del (13q14) (43.3%), followed by trisomy of chromosome 12 (23.3%), del (atm) (13.3%) and del (p53) (10.0%). There were no significant differences between molecular cytogenetic aberrations and sex, age, Binet stage, peripheral lymphocyte count, or the serum levels of lactate dehydrogenase (LDH), beta(2)-microglobulin (beta(2)-MG), or ZAP-70. The incidence of atm gene deletion was higher in the group of CD38 high expression than that in the group of low expression (p = 0.035). It is concluded that FISH is a rapid and sensitive technique in analysing molecular cytogenetic abnormalities, but its prognostic significance in CLL needs to further investigate.
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PMID:[Detection of molecular cytogenetic abnormalities in 30 patients with chronic lymphocytic leukemia by fluorescence in situ hybridization]. 1923 42

Chronic lymphocytic leukaemia (CLL), the commonest form of leukaemia in adults in Western countries, is a genetically heterogeneous disease. The most frequent genetic alterations are deletions in 13q14, 17p13 (TP53) and 11q22-q23 (ATM), and trisomy of chromosome 12. Furthermore, additional alterations have been described. The most relevant techniques used for detection of genetic alterations in CLL include comparative genomic hybridisation (CGH) and fluorescence in situ hybridisation (FISH). Recently, PCR-based techniques, such as multiplex ligation- dependent probe amplification (MLPA), have been used to detect genetic alterations in CLL. This review summarises the genetic alterations described in CLL and the techniques used for their detection.
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PMID:Genetic alterations in chronic lymphocytic leukaemia. 1938 Feb 95

We describe a 79-year-old patient who presented with fatigue, weight loss, pancytopenia and a papular exanthem. Previous attempts to taking bone-marrow biopsies had resulted in a 'dry tap', with no material collected, suggesting idiopathic myelofibrosis. Histological examination of skin biopsies showed dermal infiltration of monocytoid cells, resulting in a diagnosis of acute myeloid leukaemia (French-American-British M5 morphology) with leukaemia cutis (LC). Numerous abnormalities of chromosome 8 (trisomy or tetrasomy) have been identified in association with LC. We performed fluorescent in situ analysis on cutaneous tissue using directly labelled probes for various gene loci often involved in patients with AML; these tests showed deletion of p53 and excluded trisomy 8. However, application of probes for AML/ETO, MYC and telomere 8q revealed a gain at 8q22/8q24/8q telomere in a significant number of infiltrating cells. We hypothesize that a partial gain at 8q rather than trisomy of the whole chromosome 8 exhibits an association with LC in AML.
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PMID:Papular exanthem discloses acute myeloid leukaemia: interphase fluorescence in situ hybridization revealed deletion of p53 and gain at 8q22/8q24/Tel8q without trisomy 8. 1943 43

Oligodendroglial tumors presenting loss of heterozygosity (LOH) at 1p and 19q have been shown to be sensitive to chemotherapy, thus making 1p-19q status testing a key aspect in oligodendroglioma diagnosis and prognosis. Twenty-nine tumor samples (19 oligodendrogliomas, 10 oligoastrocytomas) were analyzed in order to obtain a molecular profile identifying those bearing 1p-19q LOH. Other genomic anomalies usually present in gliomas, such as EGFR amplification, CDKN2A/ARF deletion, 10q LOH and TP53 mutation, were also studied. Tumors with 1p-19q LOH overexpressed genes related to neurogenesis. Genes linked to immune response, proliferation and inflammation were overexpressed in the group with intact 1p-19q; this group could in turn be further divided in two subgroups: one overexpressing genes involved in immune response and inflammation that did not show major genetic aberrations other than the TP53 mutation and EGFR trisomy in a few cases, and another overexpressing genes related to immune response and proliferation that had a predominance of samples carrying several anomalies and presenting worse outcomes. This molecular signature was validated by analyzing a set of ten tumor samples (three oligodendrogliomas, seven oligoastrocytomas); all ten samples were correctly assigned. LOH at 1p-19q results in haploinsufficiency and copy number reduction of several genes, including NOTCH 2; this phenomenon produces a global change in gene expression inducing a pro-neural status that results in restrictions to cell migration and proliferation. Tumors without LOH at 1p-19q exhibit the opposite characteristics, explaining their more aggressive behavior.
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PMID:Loss of heterozygosity at 1p-19q induces a global change in oligodendroglial tumor gene expression. 1959 1

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is common in the Western world. Genetic abnormalities detected by fluorescence in situ hybridization (FISH) and immunoglobulin heavy chain variable gene region (IGHV) mutational status are well-known independent prognostic indicators in CLL/SLL. Given the requirement for specialized testing to detect such aberrations, we investigated whether morphologic features may predict the presence of a more or less favorable genetic profile. Forty-one SLL cases were morphologically evaluated for expanded proliferation centers, increased large cells outside of proliferation centers, and nuclear contour irregularities (NCI) in small and large tumor cells. ZAP-70 immunohistochemistry and FISH (deletions of 13q14, p53 and ATM and trisomy 12) were successful in all cases. IGHV mutational status was determined in 26/41 cases. Significant NCI in both small and large cells correlated with the presence of an unfavorable FISH abnormality (ie, ATM or p53 deletions). However, despite good specificity (94%), the sensitivity (57%) of this finding is inadequate for routine use. No other significant associations with morphologic features were identified. Strong ZAP-70 positivity correlated with unmutated IGHV (P=0.001), rendering ZAP-70 IHC a useful surrogate for IGHV mutational status. ZAP-70 positivity predicted against finding a favorable FISH deletion 13q14 (P=0.023). Although we only studied 41 cases, we corroborated their validity using Kaplan-Meier overall survival analysis. In conclusion, morphologic features in SLL are not a reliable predictor of underlying genetic status. Thus, we propose a practical, cost-effective approach to the work-up of these cases, which should be driven by clinical necessity.
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PMID:Most morphologic features in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) do not reliably predict underlying FISH genetics or immunoglobulin heavy chain variable region somatic mutational status. 1982 50

B-cell chronic lymphocytic leukemia (CLL) follows a heterogeneous clinical course, for which several biological markers may predict clinical outcome. Cytogenetic aberrations are considered major prognostic indicators for predicting the survival of CLL patients. Given the difficulties in obtaining abnormal metaphases in CLL, fluorescent in situ hybridization (FISH) with specific probes is generally used to detect the most frequent abnormalities. To determine the best strategy for identifying cytogenetic abnormalities, we compared results obtained by FISH analysis on peripheral blood mononuclear cells with those obtained by FISH after culture with mitogens. We studied 46 CLL patients selected from two different institutions. The most frequent structural aberrations leading to loss of genetic material were loss of the 13q14 region, in 32 cases (70%), and loss of TP53 in 11 cases (24%). Of the 46 cases patients, 10 patients (21.7%) had deletion of the ATM locus at 11q22 and 8 patients (17%) had trisomy 12. Results could be interpreted as discordant in four cases in which the abnormal clone was small and both values were around the threshold. FISH performed on stimulated cells detected the same frequency of abnormalities as FISH performed without culture. This equivalence between the two techniques allows performing both conventional cytogenetic and FISH analyses on the same sample.
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PMID:Detection of chromosomal abnormalities associated with chronic lymphocytic leukemia: what is the best method? 1983 67

MicroRNAs (miRNAs) regulate the expression of multiple proteins in a dose-dependent manner. We hypothesized that increased expression of miRNAs encoded on chromosome 21 (chr 21) contribute to the leukemogenic function of trisomy 21. The levels of chr 21 miRNAs were quantified by qRT-PCR in four types of childhood acute lymphoblastic leukemia (ALL) characterized by either numerical (trisomy or tetrasomy) or structural abnormalities of chr 21. Suprisingly, high expression of the hsa-mir-125b-2 cluster, consisting of three miRNAs, was identified in leukemias with the structural ETV6/RUNX1 abnormality and not in ALLs with trisomy 21. Manipulation of ETV6/RUNX1 expression and chromatin immunoprecipitation studies showed that the high expression of the miRNA cluster is an event independent of the ETV6/RUNX1 fusion protein. Overexpression of hsa-mir-125b-2 conferred a survival advantage to Ba/F3 cells after IL-3 withdrawal or a broad spectrum of apoptotic stimuli through inhibition of caspase 3 activation. Conversely, knockdown of the endogenous miR-125b in the ETV6/RUNX1 leukemia cell line REH increased apoptosis after Doxorubicin and Staurosporine treatments. P53 protein levels were not altered by miR-125b. Together, these results suggest that the expression of hsa-mir-125b-2 in ETV6/RUNX1 ALL provides survival advantage to growth inhibitory signals in a p53-independent manner.
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PMID:Hsa-mir-125b-2 is highly expressed in childhood ETV6/RUNX1 (TEL/AML1) leukemias and confers survival advantage to growth inhibitory signals independent of p53. 1989 Mar 72

Hemizygous TP53 gene deletion is the most important adverse risk factor in chronic lymphocytic leukemia (CLL), but its relationship with p53 protein expression is unclear. We investigated 110 CLL cases and correlated nuclear p53 protein immunoreactivity with TP53 gene deletion status and other CLL-associated genetic risk factors. Fluorescence in situ hybridization detected hemizygous TP53 deletions in 15 cases (13.6%), whereas immunohistochemical analysis detected nuclear p53 protein expression in 14 (12.7%). All cases expressing nuclear p53 protein had hemizygous TP53 deletions. Hemizygous TP53 gene deletion and p53 protein expression were strongly correlated (P < .001). There was no association between p53 expression and del(13q), del(11q) or trisomy 12 in CLL cases. Our data indicate that nuclear p53 protein expression, detected by a widely available immunohistochemical method, is strongly associated with TP53 deletion and that p53 immunohistochemical analysis may be adopted as a rapid, robust diagnostic tool for risk stratification of CLL.
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PMID:Aberrant nuclear p53 expression predicts hemizygous 17p (TP53) deletion in chronic lymphocytic leukemia. 2117 42

This study was aimed to investigate the common chromosomal aberrations in chronic lymphocytic leukemia (CLL) and to explore the relationship between these chromosomal aberrations and clinical features of CLL. Sequence-specific DNA probes (D13S25, RB1, p53, ATM) and one centromeric probe CSP12 were applied to detect del(13q14), del(17p13), del(11q22-q23) and trisomy 12 by using interphase fluorescence in situ hybridization (I-FISH). 9 CLL patients with negative conventional cytogenetics or without mitotic figure were enrolled in this study. The threshold was established using 10 controls without hematopoietic malignancies. The results indicated that compared with the established threshold, all of the 9 CLL patients showed cytogenetic abnormalities. The detection using p53 and D13S25 showed positive in 7 cases, positive was observed in 5 cases by using ATM and in 4 cases by using both RB1 and CSP12. There was significant correlation between the ATM and the hemoglobin level of the patients. In addition, the elevated probability of gaining bulky lymphadenopathy was found in ATM positive patients. It is concluded that the I-FISH is a more rapid and sensitive technique for analysis of chromosome aberrations in CLL. A large series study with long-term follow-up is needed to reveal the role of cytogenetic abnormalities in the determination of CLL prognosis.
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PMID:[Chromosomal aberrations in chronic lymphocytic leukemia by interphase fluorescence in situ hybridization and their association with clinical features]. 2041 97


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