| 1. |
- Balgobind, Brian V, et al.
(författare)
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Novel prognostic subgroups in childhood 11q23/MLL-rearranged acute myeloid leukemia : results of an international retrospective study.
- 2009
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 114:12, s. 2489-2496
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Tidskriftsartikel (refereegranskat)abstract
- Translocations involving chromosome 11q23 frequently occur in pediatric acute myeloid leukemia (AML) and are associated with poor prognosis. In most cases, the MLL gene is involved, and more than 50 translocation partners have been described. Clinical outcome data of the 11q23-rearranged subgroups are scarce because most 11q23 series are too small for meaningful analysis of subgroups, although some studies suggest that patients with t(9;11)(p22;q23) have a more favorable prognosis. We retrospectively collected outcome data of 756 children with 11q23- or MLL-rearranged AML from 11 collaborative groups to identify differences in outcome based on translocation partners. All karyotypes were centrally reviewed before assigning patients to subgroups. The event-free survival of 11q23/MLL-rearranged pediatric AML at 5 years from diagnosis was 44% (+/- 5%), with large differences across subgroups (11% +/- 5% to 92% +/- 5%). Multivariate analysis identified the following subgroups as independent prognostic predictors: t(1;11)(q21;q23) (hazard ratio [HR] = 0.1, P = .004); t(6;11)(q27;q23) (HR = 2.2, P < .001); t(10;11)(p12;q23) (HR = 1.5, P = .005); and t(10;11)(p11.2;q23) (HR = 2.5, P = .005). We could not confirm the favorable prognosis of the t(9;11)(p22;q23) subgroup. We identified large differences in outcome within 11q23/MLL-rearranged pediatric AML and novel subgroups based on translocation partners that independently predict clinical outcome. Screening for these translocation partners is needed for accurate treatment stratification at diagnosis.
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| 2. |
- Hasle, Henrik, et al.
(författare)
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Monosomy 7 and deletion 7q in children and adolescents with acute myeloid leukemia : an international retrospective study.
- 2007
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Ingår i: Blood. - 0006-4971. ; 109:11, s. 4641-7
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Tidskriftsartikel (refereegranskat)abstract
- Monosomy 7 (-7) and deletion 7q \del(7q)] are rare in childhood acute myeloid leukemia (AML). We retrospectively collected data on 258 children with AML or refractory anemia with excess blasts in transformation (RAEB-T) and -7 or del(7q) with or without other cytogenetic aberrations \+/- other]. Karyotypes included -7 (n = 90), -7 other (n = 82), del(7q) (n = 21), and del(7q) other (n = 65). Complete remission (CR) was achieved in fewer patients with -7 +/- other compared with del(7q) +/- other (61% versus 89%, P < .001). Overall, the 5-year survival rate was 39% (SE, 3%). Survival was superior in del(7q) +/- other compared with -7 +/- other (51% versus 30%, P < .01). Cytogenetic aberrations considered favorable in AML \t(8;21)(q22;q22), inv(16)(p13q22), t(15;17)(q22;q21), t(9;11)(p22;q23)] (n = 24) were strongly associated with del(7q) and a higher 5-year survival rate compared with del(7q) without favorable cytogenetics (75% versus 46%, P = .03). Patients with -7 and inv(3),-5/del(5q), or + 21 had a 5-year survival rate of 5%. Stem cell transplantation analyzed as a time-dependent variable had no impact on overall survival. However, patients not achieving CR had a 31% survival rate after stem cell transplantation. Childhood AML with chromosome 7 aberrations represents a heterogeneous group of disorders with additional cytogenetic aberrations having a major prognostic impact which should be reflected in future risk-group stratification.
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| 3. |
- Forestier, Erik, et al.
(författare)
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Cytogenetic features of acute lymphoblastic and myeloid leukemias in pediatric patients with Down syndrome - an iBFM-SG study.
- 2007
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020.
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Tidskriftsartikel (refereegranskat)abstract
- Children with Down syndrome (DS) have a markedly increased risk of acute lymphoblastic and myeloid leukemias (ALL+AML). To identify chromosomal changes cooperating with +21 that may provide information on the pathogenesis of these leukemias, we analyzed 215 DS-ALL and 189 DS-AML. Unlike previous smaller series, a significant proportion of DS-ALL had the typical B-cell precursor ALL abnormalities high hyperdiploidy (HeH; 11%) and t(12;21)(p13;q22) (10%). The HeH DS-ALL were characterized by gains of the same chromosomes as non-DS-HeH, suggesting the same etiology/pathogenesis. In addition, specific genetic subtypes of DS-ALL were suggested by the significant overrepresentation of cases with +X, t(8;14)(q11;q32), and del(9p). Unlike DS-ALL, the common translocations associated with non-DS-AML were rare in DS-AML, which instead were characterized by the frequent presence of dup(1q), del(6q), del(7p), dup(7q), +8, +11, del(16q), and +21. This series of DS leukemias - the largest to date - reveals that DS-ALL is a heterogeneous disorder that comprises both t(12;21) and HeH as well as DS-related abnormalities. Furthermore, this analysis confirms that DS-AML is a distinct entity, originating through other genetic pathways than do non-DS-AML, and suggests that unbalanced changes such as dup(1q), +8, and +21 are involved in the leukemogenic process.
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| 4. |
- Nachman, James B, et al.
(författare)
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Outcome of treatment in children with hypodiploid acute lymphoblastic leukemia.
- 2007
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Ingår i: Blood. - 0006-4971. ; 110:4, s. 1112-5
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Tidskriftsartikel (refereegranskat)abstract
- One-hundred thirty-nine patients with acute lymphoblastic leukemia (ALL) and hypodiploidy (fewer than 45 chromosomes) were collected from 10 different national ALL study groups and single institutions. Patients were stratified by modal chromosome number into 4 groups: 24 to 29 (N = 46); 33 to 39 (N = 26); 40 to 43 (N = 13); and 44 (N = 54) chromosomes. Nine patients were Philadelphia chromosome (Ph) positive (4 cases: 44 chromosomes; 5 cases: 40-43 chromosomes) and were not considered further. Event-free survival (EFS) and overall survival (OS) of the remaining 130 patients were 38.5% +/- 4.4% and 49.8% +/- 4.2% at 8 years, respectively. There were no significant differences in outcome between patients with 24 to 29, 33 to 39, or 40 to 43 chromosomes. Compared with patients with fewer than 44 chromosomes, patients with 44 chromosomes had a significantly better EFS (P = .01; 8-year estimate, 52.2% vs 30.1%) and OS (P = .017; 69% vs 37.5%). For patients with 44 chromosomes, monosomy 7, the presence of a dicentric chromosome, or both predicted a worse EFS but similar OS. Doubling of the hypodiploid clone occurred in 32 patients (24-29 chromosomes [n = 25] and 33-39 chromosomes [n = 7]) and had no prognostic implication. Children and adolescents with ALL and hypodiploidy with fewer than 44 chromosomes have a poor outcome despite contemporary therapy.
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| 5. |
- Paulsson, Kajsa, et al.
(författare)
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Methylation of tumour suppressor gene promoters in the presence and absence of transcriptional silencing in high hyperdiploid acute lymphoblastic leukaemia
- 2009
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Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 144:6, s. 838-847
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Tidskriftsartikel (refereegranskat)abstract
- Promoter methylation is a common phenomenon in tumours, including haematological malignancies. In the present study, we investigated 36 cases of high hyperdiploid (> 50 chromosomes) acute lymphoblastic leukaemia (ALL) with methylation-specific multiplex ligase-dependent probe amplification to determine the extent of aberrant methylation in this subgroup. The analysis, which comprised the promoters of 35 known tumour suppressor genes, showed that 16 genes displayed abnormal methylation in at least one case each. The highest number of methylated gene promoters seen in a single case was thirteen, with all but one case displaying methylation for at least one gene. The most common targets were ESR1 (29/36 cases; 81%), CADM1 (IGSF4, TSLC1; 25/36 cases; 69%), FHIT (24/36 cases; 67%) and RARB (22/36 cases; 61%). Interestingly, quantitative reverse transcription-polymerase chain reaction showed that although methylation of the CADM1 and RARB promoters resulted in the expected pattern of downregulation of the respective genes, no difference could be detected in FHIT expression between methylation-positive and -negative cases. Furthermore, TIMP3 was not expressed regardless of methylation status, showing that aberrant methylation does not always lead to gene expression changes. Taken together, our findings suggest that aberrant methylation of tumour suppressor gene promoters is a common phenomenon in high hyperdiploid ALL.
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