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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oncogene abnormalities are thought to have a central role in some human malignant disorders, particularly Burkitt leukaemia/lymphoma and chronic myeloid leukaemia (CML). However, the extent to which specific oncogene changes determine the clinical features of these disorders is unknown. This question was studied in two groups of patients with CML negative for the Philadelphia (Ph) chromosome; one group showed clinical features typical of Ph-positive CML and the other group lacked such features. Molecular findings were compared with those of Ph-positive CML. In all ten patients there was evidence for rearrangement of the bcr (breakpoint cluster region) gene. In the four cases studied the c-abl proto-oncogene was translocated to chromosome 22 and in five cases there was transcription of a chimeric bcr-abl mRNA. Thus, the molecular abnormality is the same in both groups of Ph-negative CML and identical to that in Ph-positive CML. Factors other than the bcr/c-abl rearrangement must underlie the clinical heterogeneity of CML.
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PMID:Do oncogenes determine clinical features in chronic myeloid leukaemia? 288 97

We have determined the prevalence of amplification and rearrangements for c-myc, c-myb, c-mos, bcr, c-abl, c-Ha-ras-1, c-N-ras, and c-K-ras-2 in a total of 51 cases of human leukaemia (19 patients with AML, 13 cases with CML, 14 cases with ALL, and 5 cases with CLL). Amplifications at a level of more than 2 two copies per haploid genome are apparently very rare and were found only once for c-myb in a c-ALL patient. Oncogene rearrangements were not found except for bcr, which was rearranged in all cases of CML, and 5 cases of ALL studied. Restriction fragment lengths polymorphisms (RFLPs) were also analysed. A previously described rare 5 kb EcoRI allele at the c-mos locus was absent in our patients. Rare alleles at the c-Ha-ras-1 locus were found to be significantly more prevalent in our patients than in a control group. Transfection experiments revealed no dominant transforming oncogenes in the tumour DNA of 3 patients carrying such rare alleles.
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PMID:Oncogene amplifications, rearrangements, and restriction fragment length polymorphisms in human leukaemia. 288 56

Abnormalities in structure and expression of the proto-oncogene c-abl have been implicated in the genesis of chronic myelogenous leukemia (CML). We studied leukemic cell DNA from 42 CML patients for evidence of rearrangement and/or amplification of c-abl analogous to that described in the CML cell line K562. Using the enzymes Bgl II, Pst I, Xba I, seven patients demonstrated an atypical Southern blot pattern similar to that found in K562. Analysis of DNA from normal controls and skin fibroblast from one of the seven patients established that the atypical blot pattern was due to a restriction fragment length polymorphism rather than a gene rearrangement. Further analysis revealed that c-abl exists as two alleles, A and B, yielding three genotypes: AA, AB and BB. Inheritance was Mendelian. With respect to allele A, allele B contains a deletion of about 1 kb lying in a intronic region in close proximity to highly repetitive Alu sequences and the sequence coding for phosphotyrosine of the c-abl protein. K562 and the seven patients with similar Southern patterns were identified as AB heterozygotes. In K562, only the A allele was amplified. The frequencies of AA and AB genotypes in 37 Caucasian CML patients were 81.1% and 18.9% and in 57 unrelated normal Caucasian controls 87.7% and 12.3%, not significantly different. The BB genotype was identified in less than 1% of Caucasians. Of note, five AB patients who developed a terminal blast crisis demonstrated a 4:1 lymphoid:myeloid crisis ratio in contrast to a 2:7 lymphoid:myeloid crisis ration in nine AA patients and a similar ratio in mixed AA and AB historical controls. Otherwise, CML patients with AA and AB genotypes manifested similar clinical parameters. No patients demonstrated amplification of c-abl and analysis of four AB patients for loss of one c-abl allele during the course of their disease was negative. Thus, amplification of c-abl and loss of one c-abl allele are both infrequent in CML and do not play a significant role in the course of the disease.
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PMID:Polymorphism of the human c-abl gene: relation to incidence and course of chronic myelogenous leukemia. 289

Herbimycin A, a benzoquinonoid ansamycin antibiotic, is found to reduce intracellular phosphorylation by tyrosine protein kinase. The human chronic myelogenous leukemia cell line K562 expresses a structurally altered c-abl protein with tyrosine kinase activity. When K562 cells are induced to undergo erythroid differentiation by hemin, reduction in the intracellular level of tyrosine phosphorylation occurs. In order to understand the relationship between induction of differentiation and reduction of tyrosine phosphorylation by the c-abl gene product, the effect that herbimycin A, a selective inhibitor of intracellular tyrosine kinase activity, exerts on the differentiation of K562 cells was examined. Reduction of tyrosine phosphorylation in K562 cells by herbimycin A was observed within 1 h. Noncytotoxic concentrations of herbimycin A induced erythroid differentiation of K562 cells but not of murine erythroleukemia 745A cells. The other human myeloid leukemia cell lines (HL-60, THP-1, and U937) tested were not induced to undergo cell differentiation by this antibiotic. Herbimycin A and the other well-known inducers such as hemin, butyric acid, Adriamycin, and 1-beta-D-arabinofuranosylcytosine had additive or more than additive effects on induction of erythroid differentiation of K562 cells. With respect to inhibition of cell growth, the sensitivity of K562 cells to herbimycin A was highest in the human leukemia cell lines we tested. Noncytotoxic concentrations of herbimycin enhanced the antiproliferative effect of Adriamycin or 1-beta-D-arabinofuranosylcytosine on K562 cells. Combination therapy with herbimycin A and its derivatives may be considered for use in the treatment of some types of leukemia where tyrosine kinase activities are implicated as determinants of the oncogenic state.
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PMID:Induction of erythroid differentiation of K562 human leukemic cells by herbimycin A, an inhibitor of tyrosine kinase activity. 291 Apr 52

We studied the clinical, hematologic, cytogenetic and molecular biologic features in four patients with Philadelphia (Ph) negative chronic myeloid leukemia (CML). In all four cases the clinical and hematologic characteristics were indistinguishable from Ph positive CML. Cytogenetic analysis showed a normal karyotype in two patients and chromosomal translocations apparently not affecting chromosome 22 in the other two cases. Southern blot analysis using probes of the bcr region, demonstrated a bcr break-point in all four patients. In situ hybridization with bcr, c-abl, and c-sis probes showed unusual hybridization sites for 5'-bcr and c-abl indicating complex chromosomal rearrangements affecting three different chromosomes in the four patients investigated. Using polymerase chain reaction (PCR) followed by hybridization to oligonucleotide probes specific for the bcr-abl fusion region, the expression of a chimeric bcr-abl mRNA was detected. In these patients we demonstrated that (a) CML with a breakpoint in the bcr region without cytogenetically detectable Ph chromosome is characterized by the same genomic recombination of 5'-bcr and c-abl as CML with standard Ph translocation and (b) unusual localization of 5'-bcr and c-abl sequences caused by complex Ph translocation does not interfere with transcription of the bcr-abl fusion gene.
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PMID:Cytogenetic and molecular analysis in Philadelphia negative CML. 292 Feb 4

About 50% of the Philadelphia-positive acute leukemias undergo molecular rearrangements outside the now classical bcr sequence (or M-BCR-1) rearranged in chronic myeloid leukemia (CML). Most of the breakpoints on chromosome 22 have been shown to be clustered in a 10.8-kb region of the first intron of the BCR gene (called bcr2 or m-BCR-1). In this report we examined two cases of Ph1 acute lymphoblastic leukemia in adult patients that exhibited breakpoints in a 5-kb segment of the BCR gene first intron, 16 kb upstream of the previously described cluster, suggesting the possibility of a second minor breakpoint cluster. In addition, the breakpoints on chromosome 9 were located in a region just 5' of the c-abl exon la.
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PMID:Ph1-positive, bcr-negative acute leukemias: clustering of breakpoints on chromosome 22 in the 3' end of the BCR gene first intron. 293 Aug 40

The Philadelphia (Ph) chromosome in leukemia is invariably derived from chromosome #22. A break occurs in the long (q) arm of chromosome #22 and, in every case observed until now, all of the material from that breakpoint through the telomere of chromosome #22 has been reciprocally translocated to another chromosome, most often chromosome #9. With the t(9;22) translocation, the oncogene c-sis moves from chromosome #22 onto 9q and the oncogene c-abl moves reciprocally from chromosome #9 onto 22q. We report a new mechanism for the genesis of the Ph chromosome in chronic myelocytic leukemia (CML) involving interstitial deletion of chromosome #22 with insertion of the deleted material into another chromosome: 46,XX,dir ins(11;22)(q13;q11q13). The distal portion of chromosome #22, including the telomere, appeared to have been retained in the Ph chromosome. There was no visible involvement of chromosome #9. This insertional deletion is of potential importance in evaluating the roles of oncogenes such as c-abl and c-sis in the Ph rearrangement in the origin of leukemia.
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PMID:The Philadelphia (Ph) chromosome in leukemia. I. A new mechanism due to interstitial deletion and insertion in chronic myelocytic leukemia. 298 Nov 54

Three antisera against the mouse v-abl gene product were used to identify two potential human c-abl gene products in the chronic myelogenous leukemia cell line K562. Two antipeptide sera were generated in rabbits using the predicted amino acid sequence of the mouse v-abl gene product. One antiserum was made against a polypeptide overlapping the in vivo tyrosine phosphorylation site of murine P120gag-abl and what is believed to be a homologous tyrosine phosphorylation site of the predicted normal human c-abl gene product (v-abl 263-280). The second antipeptide serum, abl 389-403, was generated against a predicted hydrophilic peptide of the v-abl gene product. Immunoprecipitation from K562 cells metabolically labeled with [32P]orthophosphate by a mouse tumor regressor and abl 389-403 antipeptide sera detected two proteins of 190,000 and 240,000 Da. Both proteins were labeled primarily at serine and, to a much lesser extent, at tyrosine residues. Immune complex kinase assays using conditions that allow the tyrosine phosphorylation of P120gag-abl showed that in vitro phosphorylation of P190 and P240 occurs primarily at tyrosine residues. The detection of these enzymatically active human c-abl gene products is a rare observation which may be in part attributed to the c-abl gene translocation from chromosomes 9 to 22 occurring in the vast majority of chronic myelogenous leukemia patients.
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PMID:The human cellular abl gene product in the chronic myelogenous leukemia cell line K562 has an associated tyrosine protein kinase activity. 298 32

Recent developments in molecular biology related to the Ph chromosome lead us to an evaluation of knowledge regarding this chromosome. The molecular advances are related to two cellular oncogenes, c-abl and c-sis, and also to the identification and molecular cloning of specific areas of DNA (e.g., band 22q11), permitting the isolation of a probe specific for the translocation breakpoint domain. In the preponderant number of cases examined, it was found that the breakpoints at 22q11 occur within a limited region of up to 5-6 kb, for which the term "breakpoint cluster region" (bcr) has been suggested. In contrast, breaks at 9q34 seem to occur within a much larger region at the molecular level. Yet to be established is the exact genetic composition of the bcr and a determination as to whether or not the breaks leading to the disease occur preferentially within specific areas. In spite of this level of knowledge, we do not understand how the Ph chromosome participates in CML. If Ph-positive CML is ultimately associated with a cascade of gene activations, the unraveling of their nature and chronology will undoubtedly tell us much of their contribution to the biology of CML, in particular, and to neoplasia, in general. In this respect, the rather clear description of CML in cytogenetic, clinical, and laboratory terms, the relatively long chronic phase of the disease, and the association of the blastic phase with nonrandom chromosome changes (at least in the initial phases of the disease) make Ph-positive CML an excellent candidate for a model for the study of molecular events in human neoplasia.
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PMID:The Philadelphia chromosome: a model of cancer and molecular cytogenetics. 300 97

Recent data suggest that two human genes, c-abl on chromosome 9 and bcr on chromosome 22, are involved in the generation of Ph1-positive CML. To examine a possible role of these sequences in transition from chronic towards blastic phase, rearrangements within bcr were analysed in 4 patients with Ph1-positive CML during chronic and acute phase. In 3 patients bcr rearrangements were identical in both phases, while in a fourth patient with duplicated Ph1 an amplified additional bcr fragment was detected in acute phase. Northern blot analysis of blast cells of the latter patient showed a novel 10.3 kb RNA species that replaced the altered 8 kb RNA transcript usually found in Ph1-positive CML.
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PMID:Additional c-abl/bcr rearrangements in a CML patient exhibiting two ph1 chromosomes during blast crisis. 300 78


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