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: EC:5.99.1.2 (topoisomerase)
9,166 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The International Workshop on the relationship between prior therapy and balanced chromosome aberrations in therapy-related myelodysplastic syndromes (t-MDS) and therapy-related acute leukemia (t-AL) identified 79 of 511 (15.5%) patients with balanced 21q22 translocations. Patients were treated for their primary disease, including solid tumors (56%), hematologic malignancy (43%), and juvenile rheumatoid arthritis (single case), by radiation therapy (5 patients), chemotherapy (36 patients), or combined-modality therapy (38 patients). 21q translocations involved common partner chromosomes in 81% of cases: t(8;21) (n = 44; 56%), t(3;21) (n = 16; 20%), and t(16;21) (n = 4; 5%). Translocations involving 15 other partner chromosomes were also documented with involvement of AML1(CBFA2/RUNX1), identifying a total of 23 different 21q22/AML1 translocations. The data analysis was carried out on the basis of five subsets of 21q22 cases, that is, t(8;21) with and without additional aberrations, t(3;21), t(16;21), and other 21q22 translocations. Dysplastic features were present in all 21q22 cases. Therapy-related acute myeloid leukemia (t-AML) at presentation was highest in t(8;21) (82%) and lowest in t(3;21) (37.5%) patients. Cumulative drug dose exposure scores for alkylating agents (AAs) and topoisomerase II inhibitors indicated that t(3;21) patients received the most intensive therapy among the five 21q22 subsets, and the median AA score for patients with secondary chromosome 7 aberrations was double the AA score for the entire 21q22 group. All five patients who received only radiation therapy had t(8;21) t-AML. The median latency and overall survival (OS) for 21q22 patients were 39 and 14 months (mo), compared to 26 and 8 mo for 11q23 patients, 22 and 28 mo for inv(16), 69 and 7 mo for Rare recurring aberrations, and 59 and 7 mo for Unique (nonrecurring) balanced aberration (latency P < or = 0.016 for all pairwise comparisons; OS, P < or = 0.018 for all pairwise comparisons). The percentages of 21q22 patients surviving 1 year, 2 years, and 5 years were 58%, 33%, and 18%, respectively. Noticeable differences were observed in median OS between 21q22 patients (n = 7) receiving transplant (BMT) (31 mo) compared to 21q22 patients who received intensive non-BMT therapy (n = 46) (17 mo); however, this was nonsignificant because of the small sample size (log-rank, P = 0.33). t-MDS/t-AML with balanced 21q22 aberrations was associated with prior exposure to radiation, epipodophyllotoxins, and anthracyclines, dysplastic morphologic features, multiple partner chromosomes, and longer latency periods when compared to 11q23 and inv(16) t-MDS/AML Workshop subgroups. In general, patients could be divided into two prognostic risk groups, those with t(8;21) (median OS, 19 mo) and those without t(8;21) (median OS, 7 mo) leukemia (log-rank, P = 0.0007).
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PMID:21q22 balanced chromosome aberrations in therapy-related hematopoietic disorders: report from an international workshop. 1192 Dec 72

Seventy-seven patients were identified with Rare recurring (excluding 11q23, 21q22, inv(16), and t(15;17)) chromosome abnormalities among 511 patients with treatment-related myelodysplastic syndromes and acute leukemia accepted from centers in the United States, Europe, and Japan. The abnormality subsets included 3q21q26 (17 patients), 11p15 (17 patients), t(9;22)(q34;q11) (10 patients), 12p13 (9 patients), t(8;16)(p11;p13) (9 patients), and an "other" subset, which included t(6;9)(p23;q34) (3 patients), t(10;11)(p13;q13 approximately q21) (3 patients), t(1;17)(p36;q21) (2 patients), t(8;14)(q24;q32) (2 patients), t(11;19)(q13;q13) (2 patients), t(1;3)(p36;q21) (2 patients), and t(3;5)(q21;q31) (1 patient). Increased karyotypic complexity with additional balanced and unbalanced rearrangements was observed in 70% of cases. Among 54 cases with secondary abnormalities, chromosome 5 and/or 7 abnormalities were observed in 59%. The most frequent primary diseases were breast cancer (24 cases), Hodgkin disease (14 cases), non-Hodgkin lymphoma (10 cases), and de novo ALL (5 cases). Thirty-seven patients received alkylating agents plus topoisomerase II inhibitors with or without radiation therapy. The presenting diagnosis was t-AML in 47 cases, t-MDS in 23 cases (10 progressed to t-AML), and t-ALL in seven cases, five of whom had a t(9;22). The median latency time from initiation of original therapy to therapy-related disease diagnosis was quite long (69 months), and the overall median survival from the date of therapy-related disease diagnosis was very short (7 months). The 1-year survival rate was 34 +/- 7%, with no significant differences among subsets. Comparison with previously reported cases showed increased karyotypic complexity and adult presentation of pediatric-associated chromosome abnormalities.
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PMID:Rare recurring balanced chromosome abnormalities in therapy-related myelodysplastic syndromes and acute leukemia: report from an international workshop. 1192 Dec 74

A phase I/II clinical study evaluated 17 patients with refractory/recurrent acute leukemia treated with 1.5 mg/m2/day topotecan on days 1-3 followed by etoposide (100 mg/m2/day)+mitoxantrone (10 mg/m2/day) on days 4, 5 and 9, 10. Timed sequential chemotherapy using the topoisomerase I-inhibitor topotecan before the topoisomerase II-inhibitors, etoposide+mitoxantrone (T-EM) treatment is proposed to induce topoisomerase II protein levels and potentiate the cytotoxic activity of the topoisomerase II-directed drugs. Fourteen patients had refractory and three had recurrent acute leukemia. The majority of patients were heavily pre-treated with greater than three re-induction chemotherapy regimens. Ten patients responded to T-EM treatment (59%). Four of seventeen (24%) had a complete remission and one had a partial remission. Four additional patients (24%) who scored complete leukemia clearance had no evidence of disease with complete white and red blood cell recovery but with platelet counts less than 100,000. The lack of platelet recovery in one patient having a partial response was scored as a partial leukemia clearance. The toxicity profile included major non-hematological toxicity including grade 3 mucositis (29%) and neutropenic fever (65%). Paired measurements of intracellular levels of topoisomerase II isoforms alpha and beta in leukemia blast cells (bone marrow) collected before (day 0) and after topotecan treatment (day 4) showed that a relative increase of topoisomerase IIalpha (Topo IIalpha) > or = 40% strongly correlated with response after T-EM treatment. Increased Topo IIalpha levels also corresponded to increased DNA fragmentation. Two patients who had an increase of Topo IIalpha of 20-25% had either a PR or PLC while patients with a < 10% increase showed no response to T-EM treatment. We conclude that timed sequential chemotherapy using topotecan followed by etoposide+mitoxantrone is an effective regimen for patients with refractory acute leukemia, and demonstrate Topo IIalpha protein level increases after topotecan treatment.
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PMID:Treatment of refractory acute leukemia with timed sequential chemotherapy using topotecan followed by etoposide + mitoxantrone (T-EM) and correlation with topoisomerase II levels. 1214 10

We designed a pharmacokinetic and pharmacodynamic phase I study of sequential topotecan (2.55-6.3mg/m2) by 72h infusion followed by five daily doses of etoposide for patients with refractory acute leukemia based upon synergistic anti-tumor activity of topoisomerase I and II inhibitors in vitro. Eight of the 29 patients achieved bone marrow aplasia and two patients achieved clinical remission. Common grade 3-4 toxicities included hepatic and gastrointestinal dysfunction, and correlated with increased steady-state plasma topotecan concentration. The predicted up-regulation of topoisomerase II activity by topoisomerase I inhibition was not observed at this dose and schedule and may provide insight into the modest anti-leukemia activity of the regimen.
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PMID:A phase I and pharmacodynamic study of sequential topotecan and etoposide in patients with relapsed or refractory acute myelogenous and lymphoblastic leukemia. 1247 45

The translocation t(9;11)(p22;q23) is a recurring chromosomal abnormality in acute myeloid leukemia (AML) fusing two genes designated as MLL and AF9. Within MLL, almost all rearrangements cluster in an 8.3-kb restricted region and fuse 5' portions of MLL to a variety of heterologous genes in various 11q23 translocations. AF9 is one of the most common fusion partners of MLL. It spans more than 100 kb, and two breakpoint cluster regions (BCRs) have been identified in a telomeric region of intron 4 (BCR1) and within introns 7 and 8 (BCR2). We investigated 11 children's bone marrow or peripheral blood samples (3 AML, 5 t-AML, 2 ALL, 1 ALL relapse) and two cell lines (THP-1 and Mono-Mac-6) with cytogenetically diagnosed translocations t(9;11). By use of an optimized multiplex nested long-range PCR assay, a breakpoint-spanning DNA fragment from each sample was amplified and directly sequenced. In four patients and two cell lines, the AF9 breakpoints were located within BCR1 and in two patients within BCR2, respectively. However, in five patients the AF9 breakpoints were found outside the previously described BCRs within the centromeric region of intron 4 and even within intron 3 in one case. All five patients with a secondary AML, who had not received etoposides during treatment of the primary malignant disease, revealed almost identical MLL breakpoints very close to a breakage hot spot inducible by topoisomerase II inhibitors or apoptotic triggers in vitro. Sequence patterns around the breakpoints indicated involvement of a "damage-repair mechanism" in the development of t(9;11) similar to t(4;11) in infants' acute leukemia.
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PMID:Analysis of t(9;11) chromosomal breakpoint sequences in childhood acute leukemia: almost identical MLL breakpoints in therapy-related AML after treatment without etoposides. 1261 63

Therapy-related myelodysplasia and myeloid leukemia (t-MDS/t-AML) is a distinctive clinical syndrome occurring after exposure to chemotherapy (CT) or radiotherapy (RT). We report findings on 306 consecutive patients referred to our institution with morphologic review and cytogenetic analyses. Since 1972, 141 males and 165 females with a median age of 51 years (range, 3-83 years) at primary diagnosis and 58 years (range, 6-86 years) at secondary diagnosis were analyzed. Patients had been administered various cytotoxic agents, including alkylating agents (240 patients, 78%) and topoisomerase 2 inhibitors (115 patients, 39%). One hundred twenty-one (40%) had undergone CT alone, 43 (14%) had undergone RT alone, and 139 (45%) had undergone both modalities. At diagnosis of t-MDS/t-AML, 282 (92%) had clonal abnormalities involving chromosome 5 (n = 63), chromosome 7 (n = 85), chromosomes 5 and 7 (n = 66), recurring balanced rearrangements (n = 31), other clonal abnormalities (n = 39), or normal karyotype (n = 24). Abnormalities of chromosome 5, 7, or both accounted for 76% of all cases with an abnormal karyotype. Seventeen patients acquired t-MDS/t-AML after autologous stem cell transplantation, but no unique pattern of cytogenetic abnormalities was observed. Shorter latency was observed for patients with balanced rearrangements (median, 28 vs 67 months; P <.0001). Patients with acute leukemia were more likely to have balanced rearrangement than those with myelodysplasia (28% vs 4%; P <.0001). Median survival time after diagnosis of t-MDS/t-AML was 8 months; survival at 5 years was less than 10%. These data confirm and extend previous associations between clinical, morphologic, and cytogenetic findings in t-MDS/t-AML.
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PMID:Clinical-cytogenetic associations in 306 patients with therapy-related myelodysplasia and myeloid leukemia: the University of Chicago series. 1262 43

Secondary acute leukemia (SAL) after treatment of osteosarcoma has been seldom reported in children. Two main mechanisms that can induce SAL have been described. The authors describe two patients who developed SAL after treatment with multiagent therapy. The first patient developed a secondary acute leukemia after treatment with alkylating agents and platinum compounds. The second patient had the clinical and molecular features of a secondary acute leukemia due to topoisomerase II inhibitors. The authors also discuss the data regarding cisplatin-associated SAL. Different molecular and pathogenic agents may be implicated in the development of second malignant neoplasms in long-term survivors of osteosarcomas.
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PMID:Chemotherapy-related secondary acute myeloid leukemia in patients diagnosed with osteosarcoma. 1521 23

Therapy-related myeloid leukemia (t-AML) is a distinctive clinical syndrome occurring after exposure to chemotherapy (CT) or radiotherapy (RT). We studied 306 consecutive patients referred to the University of Chicago with cytogenetic analyses. Since 1972, 141 males and 165 females with a median age of 51 years (range: 3-83 years) at primary diagnosis and 58 years (range: 6-86 years) at secondary diagnosis were analyzed. Patients had received various cytotoxic agents including alkylating agents (240 patients, 78%) and topoisomerase II inhibitors (115 patients, 39%). One hundred and twenty-one (40%) had received CT alone, 43 (14%) had received RT alone, and 139 (45%) had received both modalities. At diagnosis of t-AML, 282 (92%) had clonal abnormalities involving chromosome 5 (n=63), chromosome 7 (n=85), both chromosomes 5 and 7 (n=66), recurring balanced rearrangements (n=31), or other clonal abnormalities (n=39); 24 had a normal karyotype. Abnormalities of chromosomes 5 and/or 7 accounted for 76% of all cases with an abnormal karyotype. Seventeen patients had developed t-AML after autologous stem cell transplantation, but no unique pattern of cytogenetic abnormalities was observed. Patients presenting with acute leukemia were more likely to have a balanced rearrangement than those presenting with myelodysplasia (28% versus 4%, p<0.0001). Shorter latency was observed for patients with balanced rearrangements (median: 28 months versus 67 months; p<0.0001). Median survival after diagnosis of t-AML was 8 months; survival at 5 years was less than 10%. To gain insights into the molecular basis of this disease, we performed gene expression profiling of CD34+ hematopoietic progenitor cells from t-AML patients. We found distinct subtypes of t-AML that have characteristic gene expression patterns. Common to each of the subgroups are gene expression patterns typical of arrested differentiation in early progenitor cells. Leukemias with a -5/del(5q) have a higher expression of genes involved in cell cycle control (CCNA2, CCNE2, CDC2), checkpoints (BUB1), or growth (MYC), and loss of expression of the gene encoding interferon consensus sequence-binding protein (ICSBP). A second subgroup of t-AML is characterized by down-regulation of transcription factors involved in early hematopoiesis (TAL1, GATA1, and EKLF) and overexpression of proteins involved in signaling pathways in myeloid cells (FLT3) and cell survival (BCL2). Establishing the molecular pathways involved in t-AML may facilitate the identification of selectively expressed genes that can be exploited for the development of targeted therapies.
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PMID:Therapy-related myeloid leukaemia: a model for leukemogenesis in humans. 1593 16

Acute leukemias with balanced chromosomal translocations, protean morphologic and immunophenotypic presentations but generally shorter latency and absence of myelodysplasia are recognized as a complication of anti-cancer drugs that behave as topoisomerase II poisons. Translocations affecting the breakpoint cluster region of the MLL gene at chromosome band 11q23 are the most common molecular genetic aberrations in leukemias associated with the topoisomerase II poisons. These agents perturb the cleavage-religation equilibrium of topoisomerase II and increase cleavage complexes. One model suggests that this damages the DNA directly and leads to chromosomal breakage, which may result in untoward DNA recombination in the form of translocations. This review will summarize the evidence for topoisomerase II involvement in the genesis of translocations and extension of the model to acute leukemia in infants characterized by similar MLL translocations.
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PMID:Topoisomerase II and the etiology of chromosomal translocations. 1685 31

Secondary acute leukemia is a devastating complication in children and adolescents who have been treated for cancer. Secondary acute lymphoblastic leukemia (s-ALL) was rarely reported previously but can be distinguished today from recurrent primary ALL by comparison of immunoglobulin and T-cell receptor rearrangement. Secondary acute myeloid leukemia (s-AML) is much more common, and some cases actually may be second primary cancers. Treatment-related and host-related characteristics and their interactions have been identified as risk factors for s-AML. The most widely recognized treatment-related risk factors are alkylating agents and topoisomerase II inhibitors (epipodophyllotoxins and anthracyclines). The magnitude of the risk associated with these factors depends on several variables, including the administration schedule, concomitant medications, and host factors. A high cumulative dose of alkylating agents is well known to predispose to s-AML. The prevalence of alkylator-associated s-AML has diminished among pediatric oncology patients with the reduction of cumulative alkylator dose and limited use of the more leukemogenic alkylators. The best-documented topoisomerase II inhibitor-associated s-AML is s-AML associated with epipodophyllotoxins. The risk of s-AML in these cases is influenced by the schedule of drug administration and by interaction with other antineoplastic agents but is not consistently found to be related to cumulative dose. The unpredictable risk of s-AML after epipodophyllotoxin therapy may discourage the use of these agents, even in patients at a high risk of disease recurrence, although the benefit of recurrence prevention may outweigh the risk of s-AML. Studies in survivors of adult cancers suggest that, contrary to previous beliefs, the outcome of s-AML is not necessarily worse than that of de novo AML when adjusted for cytogenetic features. More studies are needed to confirm this finding in the pediatric patient population.
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PMID:Acute leukemia as a secondary malignancy in children and adolescents: current findings and issues. 1907 83


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