Publications by authors named "Katrine Eklo"

4 Publications

  • Page 1 of 1

MicroRNA signatures in tumor tissue related to angiogenesis in non-small cell lung cancer.

PLoS One 2012 25;7(1):e29671. Epub 2012 Jan 25.

Department of Oncology, University Hospital of North Norway, Tromsφ, Norway.

Background: Angiogenesis is regarded as a hallmark in cancer development, and anti-angiogenic treatment is presently used in non-small cell lung cancer (NSCLC) patients. MicroRNAs (miRs) are small non-coding, endogenous, single stranded RNAs that regulate gene expression. In this study we aimed to identify significantly altered miRs related to angiogenesis in NSCLC.

Methods: From a large cohort of 335 NSCLC patients, paraffin-embedded samples from 10 patients with a short disease specific survival (DSS), 10 with a long DSS and 10 normal controls were analyzed. The miRs were quantified by microarray hybridization and selected miRs were validated by real-time qPCR. The impacts of different pathways, including angiogenesis, were evaluated by Gene Set Enrichment Analysis (GSEA) derived from Protein ANalysis THrough Evolutionary Relationship (PANTHER). One of the most interesting candidate markers, miR-155, was validated by in situ hybridization (ISH) in the total cohort (n = 335) and correlation analyses with several well-known angiogenic markers were done.

Results: 128 miRs were significantly up- or down-regulated; normal versus long DSS (n = 68) and/or normal versus short DSS (n = 63) and/or long versus short DSS (n = 37). The pathway analysis indicates angiogenesis-related miRs to be involved in NSCLC. There were strong significant correlations between the array hybridization and qPCR validation data. The significantly altered angiogenesis-related miRs of high interest were miR-21, miR-106a, miR-126, miR-155, miR-182, miR-210 and miR-424. miR-155 correlated significantly with fibroblast growth factor 2 (FGF2) in the total cohort (r = 0.17, P = 0.002), though most prominent in the subgroup with nodal metastasis (r = 0.34, P<0.001).

Conclusions: Several angiogenesis-related miRs are significantly altered in NSCLC. Further studies to understand their biological functions and explore their clinical relevance are warranted.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029671PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3266266PMC
June 2012

Independent and tissue-specific prognostic impact of miR-126 in nonsmall cell lung cancer: coexpression with vascular endothelial growth factor-A predicts poor survival.

Cancer 2011 Jul 24;117(14):3193-200. Epub 2011 Jan 24.

Department of Oncology, University Hospital of North Norway, Tromso, Norway.

Background: Angiogenesis is pivotal in tumor development. Vascular endothelial growth factor-A (VEGF-A) is considered one of the most important angiogenic factors, but lately several microRNAs (miRs) have been associated with vascular development. miR-126 has been related to tumor angiogenesis and in the regulation of VEGF-A. The authors aimed to investigate the prognostic impact of miR-126 and its co-expression with VEGF-A in nonsmall cell lung cancer (NSCLC) patients.

Methods: Tumor tissue samples from 335 resected stage I to IIIA NSCLC patients were obtained and tissue microarrays (TMAs) were constructed with 4 cores from each tumor specimen. VEGF-A expression was evaluated by immunohistochemistry, and in situ hybridization was used to evaluate the expression of miR-126.

Results: In the total material, miR-126 was a significant negative prognostic factor in both univariate (P = .005) and multivariate analyses (hazard ratio [HR] 1.8, 95% confidence interval [CI] 1.2-2.8, P = .01). Stratified by histology, miR-126 was only significant in squamous cell carcinomas (univariate: P < .001; multivariate: HR 3.1, CI 95% 1.7-5.6, P<.001). Stratified by lymph node status, miR-126 was significant only in the lymph node-positive subgroup (univariate: P<.001; multivariate: HR 4.1, CI 95% 2.0-8.4, P < .001). High miR-126 expression correlated significantly with high VEGF-A expression (P = .037). The co-expression of miR-126 and VEGF-A had a significant prognostic impact (P = .002), with 5-year survival rates of 68%, 51%, and 42% for low/low (n = 150), mixed combinations (n = 129), and high/high (n = 35) expression, respectively.

Conclusions: miR-126 is a strong and independent negative prognostic factor in NSCLC, and its prognostic impact appears related primarily to histology and nodal status.
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http://dx.doi.org/10.1002/cncr.25907DOI Listing
July 2011

Prognostic impact of MiR-155 in non-small cell lung cancer evaluated by in situ hybridization.

J Transl Med 2011 Jan 10;9. Epub 2011 Jan 10.

Department of Oncology, University Hospital of North Norway, Tromso, Norway.

Background: In recent years, microRNAs (miRNAs) have been found to play an essential role in tumor development. In lung tumorigenesis, targets and pathways of miRNAs are being revealed, and further translational research in this field is warranted. MiR-155 is one of the miRNAs most consistently involved in various neoplastic diseases. We aimed to investigate the prognostic impact of the multifunctional miR-155 in non-small cell lung cancer (NSCLC) patients.

Methods: Tumor tissue samples from 335 resected stage I to IIIA NSCLC patients were obtained and tissue microarrays (TMAs) were constructed with four cores from each tumor specimen. In situ hybridization (ISH) was used to evaluate the expression of miR-155.

Results: There were 191 squamous cell carcinomas (SCCs), 95 adenocarcinomas (ACs), 31 large cell carcinomas and 18 bronchioalveolar carcinomas. MiR-155 expression did not have a significant prognostic impact in the total cohort (P = 0.43). In ACs, high miR-155 expression tended to a significant negative prognostic effect on survival in univariate analysis (P = 0.086) and was an independent prognostic factor in multivariate analysis (HR 1.87, CI 95% 1.01 - 3.48, P = 0.047). In SCC patients with lymph node metastasis, however, miR-155 had a positive prognostic impact on survival in univariate (P = 0.034) as well as in multivariate (HR 0.45, CI 95% 0.21-0.96, P = 0.039) analysis.

Conclusions: The prognostic impact of miR-155 depends on histological subtype and nodal status in NSCLC.
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http://dx.doi.org/10.1186/1479-5876-9-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3023703PMC
January 2011

APC mutation spectrum of Norwegian familial adenomatous polyposis families: high ratio of novel mutations.

J Cancer Res Clin Oncol 2009 Oct 15;135(10):1463-70. Epub 2009 May 15.

Pathology Division, University Hospital of Oslo-Rikshospitalet, N0027 Oslo, Norway.

Introduction: Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited disease caused by mutations in the adenomatous polyposis coli (APC) gene. Massive formation of colorectal adenomas, of which some will inevitably develop into adenocarcinomas, is the hallmark of the disease. Characterization of causative APC mutations allows presymptomatic diagnosis, close follow-up and prophylactic intervention in families. To date more than 900 different germline mutations have been characterized worldwide demonstrating allelic heterogeneity.

Purpose: The germline mutation spectrum of APC identified in 69 apparently unrelated Norwegian FAP families are presented and discussed with reference to clinical phenotype and novel mutation rate.

Methods: Different methods have been used over the years. However, all mutations were confirmed detectable by an implemented denaturing high-performance liquid chromatography screening approach. Multiplex ligation-dependent probe amplification analysis was employed for potential gross rearrangements.

Results: Fifty-three distinctive mutations were detected, of which 22 have been detected in Norway exclusively. Except for two major deletion mutations encompassing the entire APC, all mutations resulted in premature truncation of translation caused by non-sense (31%) or change in reading frame (69%).

Conclusion: A high ratio of novel APC mutations continues to contribute to APC mutation heterogeneity causing FAP. This is the first comprehensive report of APC germline mutation spectrum in Norway.
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http://dx.doi.org/10.1007/s00432-009-0594-4DOI Listing
October 2009
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