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- Frost, Britt-Marie, et al.
(författare)
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Translocation t(12;21) is related to in vitro cellular drug sensitivity to doxorubicin and etoposide in childhood acute lymphoblastic leukemia
- 2004
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Ingår i: Blood. - Washington : American society of hematology. - 0006-4971 .- 1528-0020. ; 104:8, s. 2452-2457
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Tidskriftsartikel (refereegranskat)abstract
- The t(12;21) (p13;q22) translocation resulting in ETV6/RUNX1 (previously named TEL/AML1) gene fusion is present in about 25% of children with precursor B-lineage acute lymphoblastic leukemia (B-ALL). We successfully tested 275 precursor BALL samples from children aged 1 to 17 years to determine the relation between t(12;21) and in vitro cellular drug resistance, measured by the fluorometric microculture cytotoxicity assay (FMCA). Samples from 83 patients (30%) were positive for t(12;21). The ETV6/RUNX1(+) samples were significantly more sensitive than ETV6/RUNX1(-) samples to doxorubicin, etoposide, amsacrine, and dexamethasone, whereas the opposite was true for cytarabine. After matching for unevenly distributed patient characteristics, that is, excluding patients with high hyperdiploidy (> 51 chromosomes), t(g;22), t(1;19), or 11q23 rearrangement, the ETV6/RUNX1(+) samples remained significantly more sensitive to doxorubicin (P = .001) and etoposide (P = .001). For the other drugs tested (amsacrine, cytarabine, dexamethasone, prednisolone, vincristine, 6-thioguanine, and 4-hydroper-oxy-cyclophosphamide), no significant difference in cellular drug sensitivity was found. In conclusion, we found that the presence of the t(12;21) translocation in childhood precursor B-ALL is associated with a high tumor cell sensitivity to doxorubicin and etoposide. High throughput techniques should now be used to elucidate the cellular mechanisms by which ETV6/RUNX1 gene fusion is linked to increased sensitivity to these drugs.
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- Lindhagen, Elin, et al.
(författare)
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Significant cytotoxic activity in vitro of the EGFR tyrosine kinase inhibitor gefitinib in acute myeloblastic leukaemia.
- 2008
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Ingår i: Eur J Haematol. - : Wiley. - 1600-0609 .- 0902-4441. ; 81:5, s. 344-353
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES:Gefitinib inhibits epidermal growth factor receptor (EGFR) signalling, but may also act by non-EGFR dependent mechanisms. We have investigated the activity of gefitinib in haematological tumour cells, in particular acute myeloblastic leukaemia (AML).METHODS:Cytotoxic activity of gefitinib, alone or in combination with standard anti-leukaemic drugs, was assessed by the short-term fluorometric microculture cytotoxicity assay in tumour cells from 117 patients representing five haematological and five non-haematological malignancies. In AML, the EGFR status was analysed by immunochemistry. Gefitinib-induced apoptosis was investigated in a subset of AML samples, as well as in the leukaemia cell line MV-4-11, using a multiparametric high content screening assay. To confirm activation of caspase-3 in cells treated with gefitinib, a blocking test was carried out in which MV4-11 cells were pretreated with the specific caspase inhibitor DEVD-FMK.RESULTS:Gefitinib showed highest cytotoxic activity in AML (n = 19) with many samples being sensitive at concentrations achievable in clinical practice (<10 microM), and no difference between previously untreated and relapsed patients. No correlation between the activity of gefitinib and standard antileukaemic drugs (cytarabine, doxorubicin, etoposide) was observed. Combining gefitinib with these drugs resulted in mainly additive or synergistic (etoposide) effects, with no evidence of sequence dependency. The AML cells did not express the EGFR. Gefitinib induced apoptosis, which was at least partly mediated by activation of the caspase-3 pathway.CONCLUSION:In vitro, gefitinib has significant cytotoxic activity in AML by inducing apoptosis through non-EGFR dependent pathways.
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| 4. |
- Lindqvist, C Mårten, et al.
(författare)
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The Mutational Landscape in Pediatric Acute Lymphoblastic Leukemia Deciphered by Whole Genome Sequencing
- 2015
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 36:1, s. 118-128
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Tidskriftsartikel (refereegranskat)abstract
- Genomic characterization of pediatric acute lymphoblastic leukemia (ALL) has identified distinct patterns of genes and pathways altered in patients with well-defined genetic aberrations. To extend the spectrum of known somatic variants in ALL, we performed whole genome and transcriptome sequencing of three B-cell precursor patients, of which one carried the t(12;21)ETV6-RUNX1 translocation and two lacked a known primary genetic aberration, and one T-ALL patient. We found that each patient had a unique genome, with a combination of well-known and previously undetected genomic aberrations. By targeted sequencing in 168 patients, we identified KMT2D and KIF1B as novel putative driver genes. We also identified a putative regulatory non-coding variant that coincided with overexpression of the growth factor MDK. Our results contribute to an increased understanding of the biological mechanisms that lead to ALL and suggest that regulatory variants may be more important for cancer development than recognized to date. The heterogeneity of the genetic aberrations in ALL renders whole genome sequencing particularly well suited for analysis of somatic variants in both research and diagnostic applications.
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| 6. |
- Lönnerholm, Gudmar, 1941-, et al.
(författare)
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In vitro cellular drug resistance adds prognostic information to other known risk-factors in childhood acute lymphoblastic leukemia
- 2011
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Ingår i: Leukemia research. - : Elsevier. - 0145-2126 .- 1873-5835. ; 35:4, s. 472-478
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Tidskriftsartikel (refereegranskat)abstract
- Leukemic cells from 230 children with newly diagnosed B-cell precursor ALL were tested for in vitro drug resistance to a panel of anti-cancer drugs. Minimal residual disease (MRD) was measured by RQ-PCR. During follow-up, 24 relapses occurred in the 159 children with MRD <0.1% day 29. The risk of any relapse was correlated to vincristine and doxorubicin resistance, with a relative risk of 3.7 (95% CI 1.3-10.5; p=0.016) for patients resistant to both drugs. There was a significant correlation also for the subgroup with extra-medullary relapses. Our findings indicate that analysis of drug resistance can add prognostic information to other known risk-factors including MRD.
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| 7. |
- Lönnerholm, Gudmar, et al.
(författare)
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In vitro cellular drug sensitivity at diagnosis is correlated to minimal residual disease at end of induction therapy in childhood acute lymphoblastic leukemia.
- 2009
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Ingår i: Leukemia research. - Oxford : Elsevier BV. - 0145-2126 .- 1873-5835. ; 33:1, s. 46-53
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Tidskriftsartikel (refereegranskat)abstract
- Leukemic cells from 85 children with newly diagnosed precursor B-lineage ALL were tested for in vitro drug sensitivity to a panel of anti-cancer drugs. Minimal residual disease (MRD) was measured by RQ-PCR. There was a significant correlation between MRD day 29 and in vitro sensitivity to prednisolone (p<0.001) and doxorubicin (p=0.017), drugs administered during induction therapy. In patients with t(12;21) (n=20), in vitro sensitivity to doxorubicin was an independent factor for MRD <0.1% (p=0.031; R(2)=0.66). Thus, data show that in vitro drug sensitivity at diagnosis is correlated to cell kill during induction therapy as measured by MRD day 29.
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| 8. |
- Nordlund, Jessica, et al.
(författare)
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DNA methylation-based subtype prediction for pediatric acute lymphoblastic leukemia
- 2015
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Ingår i: Clinical Epigenetics. - : Springer Science and Business Media LLC. - 1868-7083 .- 1868-7075. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: We present a method that utilizes DNA methylation profiling for prediction of the cytogenetic subtypes of acute lymphoblastic leukemia (ALL) cells from pediatric ALL patients. The primary aim of our study was to improve risk stratification of ALL patients into treatment groups using DNA methylation as a complement to current diagnostic methods. A secondary aim was to gain insight into the functional role of DNA methylation in ALL. Results: We used the methylation status of similar to 450,000 CpG sites in 546 well-characterized patients with T-ALL or seven recurrent B-cell precursor ALL subtypes to design and validate sensitive and accurate DNA methylation classifiers. After repeated cross-validation, a final classifier was derived that consisted of only 246 CpG sites. The mean sensitivity and specificity of the classifier across the known subtypes was 0.90 and 0.99, respectively. We then used DNA methylation classification to screen for subtype membership of 210 patients with undefined karyotype (normal or no result) or non-recurrent cytogenetic aberrations('other' subtype). Nearly half (n = 106) of the patients lacking cytogenetic subgrouping displayed highly similar methylation profiles as the patients in the known recurrent groups. We verified the subtype of 20% of the newly classified patients by examination of diagnostic karyotypes, array-based copy number analysis, and detection of fusion genes by quantitative polymerase chain reaction (PCR) and RNA-sequencing (RNA-seq). Using RNA-seq data from ALL patients where cytogenetic subtype and DNA methylation classification did not agree, we discovered several novel fusion genes involving ETV6, RUNX1, and PAX5. Conclusions: Our findings indicate that DNA methylation profiling contributes to the clarification of the heterogeneity in cytogenetically undefined ALL patient groups and could be implemented as a complementary method for diagnosis of ALL. The results of our study provide clues to the origin and development of leukemic transformation. The methylation status of the CpG sites constituting the classifiers also highlight relevant biological characteristics in otherwise unclassified ALL patients.
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| 9. |
- Nordlund, Jessica, et al.
(författare)
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Genome-wide signatures of differential DNA methylation in pediatric acute lymphoblastic leukemia
- 2013
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 14:9, s. r105-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Although aberrant DNA methylation has been observed previously in acute lymphoblastic leukemia (ALL), the patterns of differential methylation have not been comprehensively determined in all subtypes of ALL on a genome-wide scale. The relationship between DNA methylation, cytogenetic background, drug resistance and relapse in ALL is poorly understood.RESULTS:We surveyed the DNA methylation levels of 435,941 CpG sites in samples from 764 children at diagnosis of ALL and from 27 children at relapse. This survey uncovered four characteristic methylation signatures. First, compared with control blood cells, the methylomes of ALL cells shared 9,406 predominantly hypermethylated CpG sites, independent of cytogenetic background. Second, each cytogenetic subtype of ALL displayed a unique set of hyper- and hypomethylated CpG sites. The CpG sites that constituted these two signatures differed in their functional genomic enrichment to regions with marks of active or repressed chromatin. Third, we identified subtype-specific differential methylation in promoter and enhancer regions that were strongly correlated with gene expression. Fourth, a set of 6,612 CpG sites was predominantly hypermethylated in ALL cells at relapse, compared with matched samples at diagnosis. Analysis of relapse-free survival identified CpG sites with subtype-specific differential methylation that divided the patients into different risk groups, depending on their methylation status.CONCLUSIONS:Our results suggest an important biological role for DNA methylation in the differences between ALL subtypes and in their clinical outcome after treatment.
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