| 2. |
- Schleiermacher, Gudrun, et al.
(författare)
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Emergence of New ALK Mutations at Relapse of Neuroblastoma
- 2014
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology: JCO. - 0732-183X .- 1527-7755. ; 32:25, s. 2727-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose In neuroblastoma, the ALK receptor tyrosine kinase is activated by point mutations. We investigated the potential role of ALK mutations in neuroblastoma clonal evolution. Methods We analyzed ALK mutations in 54 paired diagnosis-relapse neuroblastoma samples using Sanger sequencing. When an ALK mutation was observed in one paired sample, a minor mutated component in the other sample was searched for by more than 100,000 x deep sequencing of the relevant hotspot, with a sensitivity of 0.17%. Results All nine ALK-mutated cases at diagnosis demonstrated the same mutation at relapse, in one case in only one of several relapse nodules. In five additional cases, the mutation seemed to be relapse specific, four of which were investigated by deep sequencing. In two cases, no mutation evidence was observed at diagnosis. In one case, the mutation was present at a subclonal level (0.798%) at diagnosis, whereas in another case, two different mutations resulting in identical amino acid changes were detected, one only at diagnosis and the other only at relapse. Further evidence of clonal evolution of ALK-mutated cells was provided by establishment of a fully ALK-mutated cell line from a primary sample with an ALK-mutated cell population at subclonal level (6.6%). Conclusion In neuroblastoma, subclonal ALK mutations can be present at diagnosis with subsequent clonal expansion at relapse. Given the potential of ALK-targeted therapy, the significant spatiotemporal variation of ALK mutations is of utmost importance, highlighting the potential of deep sequencing for detection of subclonal mutations with a sensitivity 100-fold that of Sanger sequencing and the importance of serial samplings for therapeutic decisions.
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| 3. |
- Schönherr, Christina, et al.
(författare)
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The neuroblastoma ALK(I1250T) mutation is a kinase-dead RTK in vitro and in vivo
- 2011
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Ingår i: Translational Oncology. - : Elsevier BV. - 1944-7124 .- 1936-5233. ; 4:4, s. 258-265
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Activating mutations in the kinase domain of anaplastic lymphoma kinase (ALK) have recently been shown to be an important determinant in the genetics of the childhood tumor neuroblastoma. Here we discuss an in-depth analysis of one of the reported gain-of-function ALK mutations—ALKI1250T—identified in the germ line DNA of one patient. Our analyses were performed in cell culture-based systems and subsequently confirmed in a Drosophila model. The results presented here indicate that the germ line ALKI1250T mutation is most probably not a determinant for tumor initiation or progression and, in contrast, seems to generate a kinase-dead mutation in the ALK receptor tyrosine kinase (RTK). Consistent with this, stimulation with agonist ALK antibodies fails to lead to stimulation of ALKI1250T and we were unable to detect tyrosine phosphorylation under any circumstances. In agreement, ALKI1250T is unable to activate downstream signaling pathways or to mediate neurite outgrowth, in contrast to the activated wild-type ALK receptor or the activating ALKF1174S mutant. Identical results were obtained when the ALKI1250T mutant was expressed in a Drosophila model, confirming the lack of activity of this mutant ALK RTK. We suggest that the ALKI1250T mutation leads to a kinase-dead ALK RTK, in stark contrast to assumed gain-of-function status, with significant implications for patients reported to carry this particular ALK mutation.
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