Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q8NB91 (FAB)
 3,573 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Myelodysplastic syndromes originate from a pluripotent stem cell. This view, previously suggested by G-6-PD and cytogenetic investigations, has been established unequivocally by X-chromosome inactivation analysis based on DNA polymorphisms and by studies of mutated oncogenes. Two genomic alterations associated with MDS have been analyzed in more detail. Activation of the RAS oncogenes, preferentially N-RAS, is demonstrated in approximately 35% of MDS patients. Mutations in the FMS gene, encoding the CSF-1 receptor, are found in 16% of cases. Interestingly, RAS and FMS mutations are predominantly observed in disorders of myelomonoctic differentiation, i.e., the CMML subtype in MDS and the AML FAB type M4. Moreover, homozygous deletion of the FMS gene may be an important event in the genesis of the MDS variant 5q- syndrome. Preliminary data indicate that defects in tumor-suppressor genes, namely p53, may also contribute to the development of MDS. Different lines of evidence suggest that clinical preleukemia is preceded by a phase in which genetic alterations accumulate without any hematologic change. Cases in point are the detection of RAS and FMS mutations in healthy individuals who had been treated in the past with cytotoxic therapy for lymphoma, the frequent observation of clonal remission in AML patients, or the identification of oncogene mutations in healthy individuals without even a history of malignancy or chemotherapy. Possibly, either germline mutations of oncogenes or tumor-suppressor genes and the process of genomic imprinting may constitute additional factors that predispose hematopoietic stem cells to malignant transformation. Limited as they are, the currently available data suggest that accumulation of genomic lesions, rather than their precise order of development with respect to one another, characterize the multistep process of leukemogenesis in which MDS already represent more advanced stages. The prognostic significance of oncogene mutations in MDS patients is controversially discussed. This issue awaits prospective analyses taking into account the influence of treatment modalities. However, the clinical relevance of molecularly defined parameters has already been established for their use as clonal markers in determining the mode of action and efficiency of different therapeutic approaches.
 ...
PMID:Molecular genetic aspects of myelodysplastic syndromes. 161 6

The median latency of 2 degrees MDS/AL is 4 to 5 years. A high percentage of patients with 2 degrees MDS/AL convert to 2 degrees AL. Survival of either is less than 1 year. A constellation of morphologic abnormalities from all 3 cell lines produces a unique appearance. Both 2 degrees MDS and 2 degrees AL are difficult to classify by the FAB system. With the exception of the identification of karyotypic abnormalities, the biology of 2 degrees MDS/AL remains largely unexplored. Alterations of chromosomes 5 and 7 predominate, but other associated cytogenetic abnormalities are being increasingly recognized. A synthesis of data regarding 2 degrees MDS/AL resulting from the treatment of several primary malignancies generates the tentative conclusions that (a) many of the alkylating agents, and the nonclassic alkylating agent procarbazine, are leukemogens; (b) melphalan is a more potent leukemogen than cyclophosphamide. None of the other alkylating agents has been clearly established to be more or less potent than another; (c) increasing duration or amount of alkylator-based chemotherapy increases the risk of leukemogenesis; (d) low doses of radiation delivered to large volumes of bone marrow are weakly leukemogenic. High doses of radiation delivered to small volumes are not. Due to the latter, there is minimal additive risk for 2 degrees MDS/AL among studies using alkylator-based chemotherapy and radiotherapy, either concurrently or sequentially; (e) the older patient (greater than 40) is at increased risk for 2 degrees MDS/AL, at least in Hodgkin's disease. Children may be at lesser risk than adults, and younger children at lesser risk than older children; (f) the risk of 2 degrees MDS/AL peaks within the first decade after treatment for the primary malignancy. The incidence rates during the second decade are low. Identified occupational/environmental risks for 2 degrees MDS/AL include benzene, ambient and diagnostic radiation exposure, and perhaps ethylene oxide. The similarities in karyotype abnormalities among leukemic cells of those whose occupations expose them to chemical hazard, and those who are exposed to cytotoxic agents, suggest that many more environmental leukemogens have yet to be discovered. Karyotype is an important prognostic factor for both achievement of CR and for survival. Nonaggressive treatment approaches have not proven useful, although the use of hematopoietic growth factors offers promise in this area. Combination chemotherapy is justified in patients with adequate performance statuses and "favorable" karyotypes. Allogeneic bone marrow transplantation is currently the only curative approach, and can be applied without attempts to first reduce the leukemic burden.
 ...
PMID:Leukemias and myelodysplastic syndromes secondary to drug, radiation, and environmental exposure. 173 70

N-ras gene activation occurs via single base substitutions in codons 12, 13, and 61. We have developed a rapid screening method, termed allele specific restriction analysis (ASRA), for detection of N-ras mutations at these three critical codons in acute myeloid leukemia (AML). Patient DNA samples are amplified by the polymerase chain reaction (PCR) by using primers that induce restriction sites in normal but not mutant N-ras alleles. We have used ASRA to identify 5 point mutations in four out of 19 patients at initial presentation of de novo AML. Three patients had one mutation at codon 12, 13, or 61 respectively, while a fourth patient had concurrent mutations at codons 12 and 13. N-ras mutations were more common in patients over 65 years of age (P less than 0.04), but did not correlate with FAB classification, attainment of complete remission, disease free survival, or overall survival. ASRA can also be used as the first step in a more sensitive approach to the detection of ras mutations. When ASRA was combined with allele specific oligonucleotide (ASO) hybridization the sensitivity and specificity of these assays were increased. This allowed identification of additional low level mutations in two patients. The data presented here constitute the first complete analysis of N-ras mutations in leukemia by ASRA and include the first identification of three concurrent N-ras mutations in a single leukemic patient. By facilitating sensitive sequential studies, ASRA should contribute to our understanding of the role of N-ras mutations in leukemogenesis.
 ...
PMID:Analysis of N-ras gene mutations in acute myeloid leukemia by allele specific restriction analysis. 195 19

Serum interleukin-2 (IL-2), soluble IL-2 receptors (sIL-2R) and tumor necrosis factor-alfa (TNF-alpha) levels were determined in 66 previously untreated consecutive patients with acute myeloid leukemia (AML) and in 22 normal volunteers. The following mean (+/- SE) values were observed in patients and controls, respectively: 35 +/- 14.7 (range 0.5-500) and 0.7 +/- 0.02 (0.5-0.8 U/ml for IL-2 (p = 0.001); 1622 +/- 289 (110-10,600) and 422 +/- 30 (207-666) U/ml for sIL-2R (p = 0.0001); 1247 +/- 196 (218-4672) and 152 +/- 11 (75-308) pg/ml for TNF-alpha (p = 0.0001). With respect to the FAB classification system, we found a significantly different distribution of serum IL-2 mean values in distinct subcategories, i.e. 3.4 +/- 1.9 U/ml in M1-M2-M3 and 42.4 +/- 20.4 U/ml in M4-M5 subgroups, respectively (p = 0.01), whereas sIL-2R and TNF-alpha levels were 1144 +/- 322 U/ml and 1120 +/- 317 pg/ml in M1-M2-M3 patients and 1945 +/- 317 U/ml and 1270 +/- 259 pg/ml in the M4-M5 group. A significantly positive correlation between TNF-alpha and sIL-2R (r = 0.53; p = 0.002) was also detected in the M4-M5 group. Sixty-three out of 66 patients received an intensive chemotherapy program. Univariate analysis showed that age and sIL-2R greater than 2000 U/ml significantly affected both complete remission rate and overall survival, whereas by multivariate analysis, age was the only independent variable significantly influencing survival. These data confirm recent in vitro evidence suggesting the role of IL-2, sIL-2R, and TNF-alpha in the control of normal hematopoiesis and leukemogenesis. Since the availability of recombinant cytokines for clinical use in AML, it is crucial to understand their spectrum of interaction in order to select the appropriate combination for in vivo administration.
 ...
PMID:Serum interleukin-2 (IL-2), soluble IL-2 receptors and tumor necrosis factor-alfa levels are significantly increased in acute myeloid leukemia patients. 199 55

Although determination of chromosomal abnormalities may be of limited usefulness for the diagnosis of leukemia, the recent advances in the molecular mechanism associated with chromosome aberration has been rapid. Chromosome translocation in Burkitt lymphoma and chronic myeloid leukemia was the most striking evidence for the oncogene activation. Other specific chromosome abnormalities for FAB-classified leukemias are also known. Translocated type of chromosome abnormalities between immunoglobulin or T-cell receptor genes and oncogenes may also affect the T and B-cell leukemogenesis. However, the role of trisomies found in human and experimental leukemias and the gene dosages had been thought to be most important until 1982, has not been unclear. Many types of phenotypically heterogeneous leukemias have been reported. t(4 ; 11) acute leukemia is one such leukemia which shows early B-cell and myelomonocytic nature. Heterogeneous leukemias have been called biphenotypic, hybrid and acute mixed leukemias. The terminology must be used the unified. Recent trials to use paraffin-fixed tissues and bone marrow smear for molecular analysis has been successfully reported. Basic analysis on the DNA degradation mechanism revealed the enzymatic activity might play an important role before the complete fixation.
 ...
PMID:[Chromosome aberrations and genes in human and experimental leukemias]. 219 1

Five patients with acute nonlymphocytic leukemia (ANLL) with chromosomal aberrations involving bands 9q21-q22 are described. The abnormalities were an interstitial deletion in two cases of ANLL FAB type M4 and M4 with eosinophilia, a terminal deletion in two cases of M4 and M5 type ANLL, and a translocation in an M2 ANLL. A review of reported cases of ANLL with abnormalities of chromosome 9 revealed a clustering of breaks at the region 9q21-q22, suggesting a possible role for these bands in leukemogenesis.
 ...
PMID:Involvement of bands 9q21-q22 in five cases of acute nonlymphocytic leukemia. 273 Nov 48

Peripheral blood mononuclear cells from a patient with acute myeloid leukemia (AML) and spleen cells from a patient with chronic myeloid leukemia (CML) were fused with HAT-sensitive human B lymphoma cells (RH-L4) in attempts to generate human monoclonal antibodies (Mab) against antigens with high specificity for myeloid leukemia cells. Forty-seven of 246 hybridomas secreted Ig that bound to AML cell surface constituents, as determined by FACS analysis of viable cells that were FITC-stained with the human Mab as the first-step reagent and FITC-conjugated rabbit anti-human Ig as second-step. Two of the 47 human Mab (one from each patient and designated AML-19 and CML-20, respectively) bound to both autologous and allogeneic myeloid leukemia cells. No significant binding was observed to cell surface constituents on human bone marrow cells, granulocytes, lymphocytes, erythrocytes, thymocytes, monocytes, lymphoblastic leukemia cells, fibroblasts, malignant B and T lymphocytic cell lines, and murine bone marrow cells. Both human Mab were IgG and were cytotoxic to myeloid leukemia cells in the presence of complement. About 70% of peripheral blood cell samples from 46 AML patients contained AML-19- and CML-20-positive cells, but the reactivity pattern had no correlation to the morphologic FAB classification of the samples. The promyelocytic HL60 cell line and the K562 cell line reacted with the two antibodies. Dot blot analysis of binding of AML-19 and CML-20 to cellular extracts immobilized on nitrocellulose paper showed that both human Mab in this assay also reacted with normal bone marrow cells. This was supported by microscopic immunofluorescence because both human Mab stained intracytoplasmatic structures in normal bone marrow cells, but both intracytoplasmatic and cell surface components stained in myeloid leukemia cells. Moreover, immunoblotting demonstrated that both human Mab in leukemia cells reacted with two cellular proteins with Mr approximately 14,500 and 18,000, and in normal bone marrow cells with a molecule with Mr approximately 20,000. Immunoprecipitation of cell membrane molecules with both the AML-19 and CML-20 antibody precipitated from leukemic cells only the molecule with Mr approximately 18,000 and no components from normal bone marrow cells. It is concluded that myeloid leukemogenesis may result in generation of cell surface expression of either new or abnormally processed molecules that are immunogenic in the autochthonous host. These molecules may also be useful as markers in diagnosis of myeloid leukemia.
 ...
PMID:Antibody-producing human-human hybridomas. III. Derivation and characterization of two antibodies with specificity for human myeloid cells. 345 56

This report describes a case of a female infant of congenital leukemia with a chromosomal translocation t(11;19) (q23;p13) which presented initially with lymphoid features and at relapse with monocytic ones. The clinical course and the results of sequential cytochemical, cytogenetic and immunological studies are considered to be consistent with the interpretation of leukemogenesis of the myelo-monocytoid progenitor cell which still retains the capability of exhibiting lymphoid features to a limited extent. Although leukemia with t(11;19) has been classified as ANLL, most commonly M5 of FAB classification, the patient with this chromosomal abnormality may have a mixed leukemia in which cells with lymphoid features and those with monocytic ones exist.
 ...
PMID:11;19 translocation in a congenital leukemia with two cell populations of lymphoblasts and monoblasts. 407 55

We report here a rare case of biphenotypic M0 acute myeloid leukemia (AML) associated with trisomy 4. The literature of trisomy 4 in acute leukemia was reviewed. M2 and M4 AML are the most common FAB subtypes associated with trisomy 4. The clinical course of this entity is generally comparable with other non-trisomy 4 cases of AML. Despite the speculation made when first described, no specific environmental toxin has been found to be associated with this entity. C-kit oncogene has been mapped to chromosome 4 recently, and the role of this proto-oncogene in leukemogenesis of trisomy 4 associated leukemia should be further investigated.
 ...
PMID:Biphenotypic M0 acute myeloid leukemia with trisomy-4. 752 17

We have previously reported the absence of mutations within exons 5-9 of the p53 gene in a panel of 30 cases of acute promyelocytic leukemia (APL), which represent the M3 FAB type of acute myeloid leukemia (AML). In the present report, we extend our analysis of p53 gene mutations to 70 cases of AML representative of the other FAB types of the disease, including M1 (16 cases), M2 (20 cases), M4 (17 cases), M5 (12 cases), and M6 (5 cases). DNAs were analyzed for p53 gene mutations in exons 5 to 9 by polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP), and direct sequencing of PCR-amplified products. Mutant p53 alleles were detected in 5 of 70 cases; 1 case in exon 5, 2 cases in exon 6, and 2 cases in exon 7. The alterations of the p53 gene were represented by point mutation leading to an amino acid substitution in four cases, and deletion in the remaining case. In four of the five cases, direct sequencing indicated the loss of the normal p53 allele; in the remaining case, two mutations were detected, presumably involving both p53 alleles. Three cases showed mutations at diagnosis; in the remaining two, the mutations were observed in clinical relapse but not at diagnosis. Our results confirm the relatively low incidence of p53 mutations in AML and further support the evidence that p53 plays a role in leukemogenesis through a recessive mechanism (two-hit model) of inactivation of tumor suppressor activity.
 ...
PMID:Analysis of p53 gene mutations in acute myeloid leukemia. 803 81


1 2 3 4 Next >>