| 1. |
- Andersson, Anna, et al.
(author)
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Microarray-based classification of a consecutive series of 121 childhood acute leukemias: prediction of leukemic and genetic subtype as well as of minimal residual disease status.
- 2007
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 21:6, s. 1198-1203
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Journal article (peer-reviewed)abstract
- Gene expression analyses were performed on 121 consecutive childhood leukemias (87 B-lineage acute lymphoblastic leukemias (ALLs), 11 T-cell ALLs and 23 acute myeloid leukemias (AMLs)), investigated during an 8-year period at a single center. The supervised learning algorithm k-nearest neighbor was utilized to build gene expression predictors that could classify the ALLs/AMLs according to clinically important subtypes with high accuracy. Validation experiments in an independent data set verified the high prediction accuracies of our classifiers. B-lineage ALLs with uncharacteristic cytogenetic aberrations or with a normal karyotype displayed heterogeneous gene expression profiles, resulting in low prediction accuracies. Minimal residual disease status (MRD) in T-cell ALLs with a high (40.1%) MRD at day 29 could be classified with 100% accuracy already at the time of diagnosis. In pediatric leukemias with uncharacteristic cytogenetic aberrations or with a normal karyotype, unsupervised analysis identified two novel subgroups: one consisting mainly of cases remaining in complete remission (CR) and one containing a few patients in CR and all but one of the patients who relapsed. This study of a consecutive series of childhood leukemias confirms and extends further previous reports demonstrating that global gene expression profiling provides a valuable tool for genetic and clinical classification of childhood leukemias.
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| 2. |
- Hallor, Karolin Hansén, et al.
(author)
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Fusion of the EWSR1 and ATF1 genes without expression of the MITF-M transcript in angiomatoid fibrous histiocytoma
- 2005
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In: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 44:1, s. 97-102
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Journal article (peer-reviewed)abstract
- Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor that usually occurs in children and young adults. Only two cases of AFH with genetic rearrangements have been reported previously; both of these had a FUS-ATF1 fusion gene. We have studied an AFH from a 9-year-old boy whose tumor displayed a t(12;22)(q13;q12) as the sole cytogenetic aberration. FISH,RT-PCR, and sequence analyses revealed an EWSR1-ATF1 fusion gene that has previously been reported in clear cell sarcoma (CCS), a soft tissue sarcoma that is morphologically and clinically distinct from AFH. This study thus has demonstrated that the EWSR1-ATF1 chimera represents a fusion gene that can be associated with different tumor types. Simultaneous expression of the EWSR1-ATF1 and MITF-M transcripts in CCS has led to the proposal that the MITF-M promoter is transactivated by EWSR1-ATF1. The AFH, however, did not express the MITF-M transcript, supporting the theory that MITF-M expression in CCS is a reflection of its cellular origin, rather than a consequence of the presence of an EWSR1-ATF1 fusion protein. Activation of the EWSR1-ATF1 oncogene is probably an early step in the transformation process, but the overall gene expression patterns are likely to vary considerably between AFH and CCS, in keeping with their clinicopathologic differences.
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| 3. |
- Lilljebjörn, Henrik, et al.
(author)
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Combined high-resolution array-based comparative genomic hybridization and expression profiling of ETV6/RUNX1-positive acute lymphoblastic leukemias reveal a high incidence of cryptic Xq duplications and identify several putative target genes within the commonly gained region
- 2007
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In: Leukemia. - : Springer Science and Business Media LLC. - 1476-5551 .- 0887-6924. ; 21:10, s. 2137-2144
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Journal article (peer-reviewed)abstract
- Seventeen ETV6/RUNX1-positive pediatric acute lymphoblastic leukemias were investigated by high-resolution array-based comparative genomic hybridization ( array CGH), gene expression profiling and fluorescence in situ hybridization. Comparing the array CGH and gene expression patterns revealed that genomic imbalances conferred a great impact on the expression of genes in the affected regions. The array CGH analyses identified a high frequency of cytogenetically cryptic genetic changes, for example, del(9p) and del(12p). Interestingly, a duplication of Xq material, varying between 30 and 60Mb in size, was found in 6 of 11 males (55%), but not in females. Genes on Xq were found to have a high expression level in cases with dup(Xq); a similar overexpression was confirmed in t(12;21)-positive cases in an external gene expression data set. By studying the expression profile and the proposed function of genes in the minimally gained region, several candidate target genes (SPANXB, HMGB3, FAM50A, HTATSF1 and RAP2C) were identified. Among them, the testis-specific SPANXB gene was the only one showing a high and uniform overexpression, irrespective of gender and presence of Xq duplication, suggesting that this gene plays an important pathogenetic role in t(12;21)-positive leukemia.
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