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| 2. |
- Gunnarsson, Rebeqa, et al.
(författare)
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Screening for copy-number alterations and loss of heterozygosity in chronic lymphocytic leukemia-A comparative study of four differently designed, high resolution microarray platforms
- 2008
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 93, s. 0536-0536
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Tidskriftsartikel (refereegranskat)abstract
- Screening for gene copy-number alterations (CNAs) has improved by applying genome-wide microarrays, where SNP arrays also allow analysis of loss of heterozygozity (LOH). We here analyzed 10 chronic lymphocytic leukemia (CLL) samples using four different high-resolution platforms: BAC arrays (32K), oligonucleotide arrays (185K, Agilent), and two SNP arrays (250K, Affymetrix and 317K, Illumina). Cross-platform comparison revealed 29 concordantly detected CNAs, including known recurrent alterations, which confirmed that all platforms are powerful tools when screening for large aberrations. However, detection of 32 additional regions present in 2-3 platforms illustrated a discrepancy in detection of small CNAs, which often involved reported copy-number variations. LOH analysis using dChip revealed concordance of mainly large regions, but showed numerous, small nonoverlapping regions and LOH escaping detection. Evaluation of baseline variation and copy-number ratio response showed the best performance for the Agilent platform and confirmed the robustness of BAC arrays. Accordingly, these platforms demonstrated a higher degree of platform-specific CNAs. The SNP arrays displayed higher technical variation, although this was compensated by high density of elements. Affymetrix detected a higher degree of CNAs compared to Illumina, while the latter showed a lower noise level and higher detection rate in the LOH analysis. Large-scale studies of genomic aberrations are now feasible, but new tools for LOH analysis are requested.
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| 3. |
- Isaksson, Sofi, et al.
(författare)
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Detecting EGFR alterations in clinical specimens-pitfalls and necessities.
- 2013
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Ingår i: Virchows Archiv: an international journal of pathology. - : Springer Science and Business Media LLC. - 1432-2307. ; 463:6, s. 755-764
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the epidermal growth factor receptor (EGFR) status in early stage lung cancer in Southern Sweden, a population for which there are no previous reports on the EGFR mutation frequency. Three hundred fifty small cell lung cancers, adenocarcinomas (AC), squamous cell carcinomas (SqCC), and large cell carcinomas were analyzed using a combination of techniques for the analysis of protein expression, gene copy numbers, and mutations. Immunohistochemical (IHC) staining with antibodies for the EGFR mutations L858R and del E746-A750 revealed intratumoral heterogeneity and several discrepant cases when compared to mutation-specific polymerase chain reaction (PCR)-based analysis. The frequencies of these two mutations, when considering IHC staining with mutation-specific antibodies in a cohort of 298 cases and subsequent confirmation by PCR, were 10 % in AC and <2 % in SqCC. Furthermore, screening by sequencing of EGFR in a cohort of 52 lung AC and squamous carcinomas demonstrated a more diverse mutation spectrum, not covered by the mutation-specific antibodies. High expression of total EGFR protein was correlated to high gene copy numbers but did not reflect the mutational status of the tumors. We believe that the mutation spectra in a Southern Swedish population is too diverse to be covered by the mutation-specific antibodies, and we also raise some other issues regarding the use of the mutation-specific antibodies, for example concerning heterogeneous expression of the mutated protein, optimal antibody dilution, and discrepancies between staining results and PCR.
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| 4. |
- Salomonsson, Annette, et al.
(författare)
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Comprehensive analysis of RNA binding motif protein 3 (RBM3) in non-small cell lung cancer
- 2020
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Ingår i: Cancer Medicine. - : Blackwell Publishing Ltd. - 2045-7634. ; 9:15, s. 5609-5619
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Tidskriftsartikel (refereegranskat)abstract
- Aims High expression of the RNA-binding motif protein 3 (RBM3) correlates with improved prognosis in several major types of cancer. The aim of the present study was to examine the prognostic value of RBM3 protein and mRNA expression in non-small cell lung cancer (NSCLC).Methods and results Immunohistochemical expression of RBM3 was evaluated in surgically treated NSCLC from two independent patient populations (n = 213 and n = 306). Staining patterns were correlated with clinicopathological parameters, overall survival (OS), and recurrence-free interval (RFI). Cases with high nuclear RBM3 protein expression had a prolonged 5-year OS in both cohorts when analyzing adenocarcinomas separately (P = .02 and P = .01). RBM3 remained an independent prognostic factor for OS in multivariable analysis of cohort I (HR 0.44, 95% CI 0.21-0.90) and for RFI in cohort II (HR 0.38, 95% CI 0.22-0.74). In squamous cell carcinoma, there was instead an insignificant association to poor prognosis. Also, the expression levels of RBM3 mRNA were investigated in 2087 lung adenocarcinomas and 899 squamous cell carcinomas assembled from 13 and 8 public gene expression microarray datasets, respectively. The RBM3 mRNA levels were not clearly associated with patient outcome in either adenocarcinomas or squamous cell carcinomas.Conclusions The results from this study support that high protein expression of RBM3 is linked to improved outcome in lung adenocarcinoma.
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| 5. |
- Salomonsson, Annette, et al.
(författare)
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Histological specificity of alterations and expression of KIT and KITLG in non-small cell lung carcinoma.
- 2013
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257. ; 52:11, s. 1088-1096
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Tidskriftsartikel (refereegranskat)abstract
- Characterization of molecules within important oncogenetic pathways may have future implications for development of therapies and biomarkers in lung cancer. One such target is the tyrosine kinase receptor KIT (c-KIT). We evaluated alterations and expression of KIT and its ligand, KITLG (also known as SCF), in 72 clinical lung tumor specimens of different histologies. Gene copy number, mRNA expression levels, and protein expression were assayed using array-based comparative genomic hybridization, real-time quantitative reverse transcription PCR and immunohistochemistry, respectively. For validation, we investigated copy number alterations and mRNA expression in external microarray data sets of 1,600 and 555 primary lung tumors, respectively. Positivity for KIT staining was most common in large cell neuroendocrine carcinoma (LCNEC) which also showed the highest KIT mRNA expression levels whereas expression was lowest in squamous cell carcinoma (SqCC). KIT mRNA expression levels were higher in KIT immunopositive samples, but expression was not affected by KIT copy numbers. Copy number gains of KIT were significantly more frequent in SqCC compared with adenocarcinoma in our own series and in the 1,600-sample data set. Immunopositivity for both KIT and KITLG in the same tumor was rare except in LCNEC. Our results highlight an increased KIT mRNA expression and frequent KIT immunopositivity in LCNEC but point out a poor correlation between KIT copy numbers and expression in SqCC, perhaps reflecting the existence of a protective mechanism against KIT alterations in this subgroup. © 2013 Wiley Periodicals, Inc.
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