| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Frost, Britt-Marie, et al.
(författare)
-
Increased in vitro cellular drug resistance is related to poor outcome in high-risk childhood acute lymphoblastic leukaemia
- 2003
-
Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 122, s. 376-
-
Tidskriftsartikel (refereegranskat)abstract
- Summary. We determined the in vitro cellular drug resistance in 370 children with newly diagnosed acute lymphoblastic leukaemia (ALL). The resistance to each of 10 drugs was measured by the fluorometric microculture cytotoxicity assay (FMCA) and was related to clinical outcome. The median follow-up time was 41 months. Risk-group stratified analyses indicated that in vitro resistance to dexamethasone, doxorubicin and amsacrine were each significantly related to the probability of disease-free survival. In the high-risk (HR) group, increased in vitro resistance to dexamethasone (P = 0·014), etoposide (P = 0·025) and doxorubicin (P = 0·05) was associated with a worse clinical outcome. Combining the results for these drugs provided a drug resistance score with an independent prognostic significance superior to that of any other factor studied, with a relative risk of relapse in the most resistant group 9·8 times that in the most sensitive group (P = 0·007). The results in the intermediate-risk (IR) and standard-risk (SR) groups were less clear cut. In conclusion, our data indicate that in vitro testing of cellular drug resistance can be used to predict the clinical outcome in HR ALL, while the final evaluation of the results in IR and SR patients must await longer follow-up.
|
|
| 5. |
- Ivanov Öfverholm, I., et al.
(författare)
-
Overexpression of chromatin remodeling and tyrosine kinase genes in iAMP21-positive acute lymphoblastic leukemia
- 2020
-
Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 61:3, s. 604-613
-
Tidskriftsartikel (refereegranskat)abstract
- Intrachromosomal amplification of chromosome 21 (iAMP21) is a cytogenetic subtype associated with relapse and poor prognosis in pediatric B-cell precursor acute lymphoblastic leukemia (BCP ALL). The biology behind the high relapse risk is unknown and the aim of this study was to further characterize the genomic and transcriptional landscape of iAMP21. Using DNA arrays and sequencing, we could identify rearrangements and aberrations characteristic for iAMP21. RNA sequencing revealed that only half of the genes in the minimal region of amplification (20/45) were differentially expressed in iAMP21. Among them were the top overexpressed genes (p < 0.001) in iAMP21 vs. BCP ALL without iAMP21 and three candidate genes could be identified, the tyrosine kinase gene DYRK1A and chromatin remodeling genes CHAF1B and SON. While overexpression of DYRK1A and CHAF1B is associated with poor prognosis in malignant diseases including myeloid leukemia, this is the first study to show significant correlation with iAMP21-positive ALL.
|
|
| 6. |
- Nordlund, Jessica, et al.
(författare)
-
Genome-wide signatures of differential DNA methylation in pediatric acute lymphoblastic leukemia
- 2013
-
Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 14:9, s. r105-
-
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.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Fehr, Andre, et al.
(författare)
-
Increased MYB alternative promoter usage is associated with relapse in acute lymphoblastic leukemia
- 2023
-
Ingår i: Genes Chromosomes & Cancer. - : John Wiley & Sons. - 1045-2257 .- 1098-2264. ; 62:10, s. 597-606
-
Tidskriftsartikel (refereegranskat)abstract
- Therapy-resistant disease is a major cause of death in patients with acute lympho-blastic leukemia (ALL). Activation of the MYB oncogene is associated with ALL and leads to uncontrolled neoplastic cell proliferation and blocked differentiation. Here, we used RNA-seq to study the clinical significance of MYB expression and MYB alter-native promoter (TSS2) usage in 133 pediatric ALLs. RNA-seq revealed that all cases analyzed overexpressed MYB and demonstrated MYB TSS2 activity. qPCR analyses confirmed the expression of the alternative MYB promoter also in seven ALL cell lines. Notably, high MYB TSS2 activity was significantly associated with relapse (p = 0.007). Moreover, cases with high MYB TSS2 usage showed evidence of therapy-resistant disease with increased expression of ABC multidrug resistance transporter genes (e.g., ABCA2, ABCB5, and ABCC10) and enzymes catalyzing drug degradation (e.g., CYP1A2, CYP2C9, and CYP3A5). Elevated MYB TSS2 activity was further associated with augmented KRAS signaling (p < 0.05) and decreased methyla-tion of the conventional MYB promoter (p < 0.01). Taken together, our results sug-gest that MYB alternative promoter usage is a novel potential prognostic biomarker for relapse and therapy resistance in pediatric ALL.
|
|
