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)

We have investigated the involvement of tumor suppressor genes (p53 and RB1) and dominantly acting oncogenes (Ras family genes) in BCR/ABL positive and negative chronic myeloproliferative disorders (CMPD) at different stages of the disease, including 26 cases of BCR/ABL+ chronic myeloid leukemia (CML) blast crisis, 9 myelosclerosis with myeloid metaplasia, 4 polycythemia vera, 10 essential thrombocythemia, 1 juvenile CML, and 8 BCR/ABL- CML. The presence of mutations in p53 exons 5 through 9, as well as in RB1 exons 10-27 and in N-, K-, H-Ras exons 1 and 2 was tested by the PCR-Single Strand Conformation Polymorphism technique and by PCR-Direct Sequencing. In addition, Southern blot analysis was used to investigate the occurrence of gross rearrangements in the p53 gene as well as loss of heterozygosity at 17p13, the site of p53. Acute phase BCR/ABL-CMPD cases displayed a high frequency of p53 (2/7) and Ras (3/7) lesions, whereas BCR/ABL- CMPD in chronic phase displayed only germline p53 and Ras sequences. Conversely, p53 inactivation was restricted to only 1/26 cases of BCR/ABL+ CML blast crisis. No alterations in the RB1 gene were detected in any of the cases analyzed. These data indicate that p53 inactivation and/or Ras activation might play a role in acute transformation of BCR/ABL- CMPD and that the molecular mechanisms of tumor progression may be different in BCR/ABL+ versus BCR/ABL-CMPD.
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PMID:Molecular mechanisms of tumor progression in chronic myeloproliferative disorders. 815

We have investigated the involvement of the p53 tumor suppressor gene and RAS family proto-oncogenes in BCR/ABL-negative chronic myeloproliferative disorders (CMPD), including nine cases of myelosclerosis with myeloid metaplasia, four polycythemia vera, 10 essential thrombocythemia, one juvenile chronic myeloid leukemia, and eight BCR/ABL-negative chronic myeloid leukemia. Twenty-five samples were studied in the chronic phase, while seven samples were analyzed in the acute accelerated or blastic phase. The presence of mutations in p53 exons 5-9, as well as in N-, K-, H-Ras exons 1 and 2 (containing codons 12, 13, and 61) was tested by the polymerase chain reaction (PCR) single strand conformation polymorphism technique and by PCR direct sequencing. In addition, restriction analysis was performed to screen for gross rearrangements within the p53 locus. Alterations of the p53 tumor suppressor gene and Ras family proto-oncogenes were detected in 2/7 and 3/7 cases of acute phase BCR/ABL-negative CMPD, respectively, while consistently negative in all the chronic phase samples analyzed. These results suggest that p53 inactivation and/or Ras activation might play a role in acute transformation of BCR/ABL-negative CMPD.
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PMID:Mutations in the P53 and RAS family genes are associated with tumor progression of BCR/ABL negative chronic myeloproliferative disorders. 832 Oct 46

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative disorders that may progress to acute leukemia in a subset of patients. This study aimed at investigating the genetic lesions associated with the blastic transformation of PV and ET. A panel of PV and ET cases at different stages of disease was analyzed for the presence of genetic alterations of TP53, NRAS, KRAS, and MDM2 by a combination of mutational analysis and Southern blot hybridization. The occurrence of microsatellite instability (MSI) was also tasted in selected cases. Samples of PV and ET analyzed in chronic phase disease were consistently devoid of all genetic lesions tested, suggesting that alterations of TP53, NRAS, KRAS, and MDM2 do not contribute significantly to development of chronic phase PV and ET. Conversely, mutations of TP53 were detected in 7/15 (46.6%) blastic phase cases, including 3/5 PV and 4/10 ET. In blastic phase patients for whom the corresponding chronic phase DNA was also available, it could be documented that the genetic lesion had arisen at the time of blastic transformation. In addition to TP53 mutations, cases of blastic phase PV and ET occasionally harbored mutations of NRAS (one case of blastic phase ET) or displayed MSI (one case of blastic phase PV). These data indicate that inactivation of TP53 is a relatively frequent event associated with the blastic transformation of PV and ET and may be responsible for the tumor progression of these disorders.
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PMID:Genetic lesions associated with blastic transformation of polycythemia vera and essential thrombocythemia. 925 60

The aim oof this study was to investigate the immunohistochemical expression of p53, mdm2, and waf1/p21 proteins in myelodysplastic syndromes (MDS), acute myelogenous leukaemias (AML), and chronic myeloproliferative disorders (CMPD). Paraffin-sections of bone marrow biopsies from 30 cases of MDS (6 cases of RAEB and RAEB-T) 22 AML (4 cases occurring in the setting of MDS), 16 chronic myeloproliferative disorders (CMPD), and 10 cases without alterations were investigated by immunohistochemistry for p53, waf1/p21, mdm2 and Ki67 proteins. P53 was detected in immature myeloid cells in 6/30 MDS (20%) and in 6/22 AML (27%) while it was not expressed in CMPD. Of the 6 p53 positive AML, 3 occurred as evolution of MDS and 3 were de novo acute leukaemias. Waf1/p21 was detected in 5/22 (23%) AML in immature myeloid cells. Waf1/p21 was also expressed in 18/30 (60%) MDS and 10/16 (63%) CMPD in variable proportion (5-25%) of the mature myeloid cells and megakaryocytes. Waf1/p21 was not detected in immature myeloid cells in MDS and CMPD. Mdm2 protein was expressed in 3/30 (10%) MDS in the immature myeloid cells and in 1/22 AML in blastic cells. The combined immunophenotypes of immature myeloid cells of MDS were: p53+/mdm2+/waf1-: 3, p53+/mdm2-/waf1-: 3, while the immunohistochemical patterns of AML were: p53+/mdm2-/waf1-: 4, p53+/mdm2+/waf1+: 1, p53+/mdm2-/waf1+: 1, p53-/mdm2-/waf1+: 3. Ki67/MIB1 staining was found in at least 30% of immature myeloid cells in MDS and AML and in at least 20% of these cells in CMPD. In conclusion, our results indicate that p53 protein is overexpressed in the myeloid lineage in a proportion of AML and MDS, while is not detected in CMPD and normal bone marrow, p53 expression was much more frequent in AML occurring as an evolution of MDS than in de novo AML. The combined immunophenotypes of p53 positive AML and MDS suggest that p53 overexpression may be due to mutation, in some AML and MDS cases with the p53+/mdm2-/waf1- phenotype. However, it would be also possible that p53 protein accumulation is not related to p53 mutation but to inhibition of p53/mdm2 binding due to mdm2 defects and/or other events related to cell stress signals. On the other hand, waf1/p21 protein overexpression without p53 expression in some AML could be p53-independent and may represent an attempt to control the high proliferation rate which was evidenced by Ki67/MIB1 immunostaining. However, the possibility of p21 to arrest cell-cycle, in these cases of AML, seems to be overridden, suggesting that cell-cycle deregulation may be involved in a proportion of AML.
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PMID:Immunohistochemical detection of p53, mdm2, waf1/p21, and Ki67 proteins in bone marrow biopsies in myelodysplastic syndroms, acute myelogenous leukaemias and chronic myeloproliferative disorders. 1059 72

Neoplastic myeloid proliferations are seen in the spleens of some patients with acute and chronic myeloproliferative disorders. Both acute myeloid leukemia (AML) and chronic myeloproliferative disorders have a variety of underlying cytogenetic defects that can be evaluated by loss of heterozygosity (LOH) studies. LOH studies have advantages over conventional cytogenetics by allowing the use of archival tissues. We evaluated the spleens in AML and chronic myeloproliferative disorders with neoplastic myeloid proliferations for the presence of LOH at several chromosome loci, and X-chromosome inactivation. A total of 17 spleens were evaluated (chronic myelogenous leukemia = 6; chronic idiopathic myelofibrosis = 6; essential thrombocythemia = 1; AML arising from previous chronic myeloproliferative disorders = 4). We examined LOH loci 7q (D7S2554), 8q (D8S263), 9p (D9S157, D9S161), 13q (D13S319), common sites of genetic abnormality in chronic myeloproliferative disorders, and TP53. In six cases, spleen LOH findings were compared to those of concurrent or preceding bone marrow biopsies. Five spleens of female patients were evaluated for the presence of clonality using X-chromosome inactivation. Of the 16 cases analyzed, 14 (88%) had at least one abnormal LOH locus, with 6/16 with two abnormal loci. The abnormalities were distributed as follows: D9S161-7/15 (47%), TP53-6/16 (38%), D7S2554-5/16 (31%), D9S157-5/15 (33%), D8S263-3/14 (21%), and D13S319-2/14 (14%). Of the six bone marrows, 4/6 showed concordance in bone marrow and spleen specimens, with additional LOH abnormalities being identified in the spleen specimens of all four cases. X-chromosome inactivation studies were showed nonrandom (clonal) patterns in two cases. Our results show that allelic losses were common in the neoplastic extramedullary hematopoiesis found in spleens of chronic myeloproliferative disorders and AML. Comparison of spleen and bone marrow specimens by LOH demonstrated additional abnormalities in the spleen compared to the marrow.
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PMID:Analysis of loss of heterozygosity and X chromosome inactivation in spleens with myeloproliferative disorders and acute myeloid leukemia. 1611 25

Spleen is a common site of extramedullary hematopoiesis. Extramedullary hematopoiesis seen in non-neoplastic conditions can occasionally be extensive and raise concerns for a myeloid neoplasm. We compared the morphologic and immunohistochemical features of splenic hematopoietic proliferations seen in neoplastic myeloid disorders (eg chronic myeloproliferative disorders, myelodysplastic/myeloproliferative disorders and acute myeloid leukemias) to extramedullary hematopoiesis seen in a variety of reactive conditions. In all, 80 spleen specimens were reviewed. The presence of each marrow-derived lineage, dysplasia and immunohistochemical results were evaluated (CD34, CD117, myeloperoxidase, CD68, p53, TdT, CD42b and hemoglobin). Neoplastic hematopoietic proliferations in chronic myeloproliferative disorders are characterized by trilineage hematopoiesis with significant dysplasia in all cell lineages. Acute myeloid leukemia showed an increase in immature forms, which were highlighted by immunohistochemistry. Reactive extramedullary hematopoiesis showed variability in histologic features. Post-bone marrow transplant and thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome spleens showed extramedullary hematopoiesis with some morphologic features of immaturity, which could simulate chronic myeloproliferative disorder. However, they lacked characteristic immunohistochemical features of neoplastic myeloid disorders such as positivity for CD34 or CD117.
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PMID:Morphologic and immunohistochemical evaluation of splenic hematopoietic proliferations in neoplastic and benign disorders. 1611 26