Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz

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Gewählte Publikation:

Benezeder, T.
Multigene Methylation Analysis of Circulating Tumor Cells in Patients with Metastatic Breast Cancer.
[ Diplomarbeit/Master Thesis (UNI) ] University of Graz; 2016.


Autor*innen der Med Uni Graz:
Benezeder Theresa Helena
Dandachi Nadia

Breast cancer is the most common malignancy with the highest mortality among women worldwide. Identification and characterization of circulating tumor cells (CTCs) is increasingly playing an important role in the effective and targeted treatment of breast cancer patients. DNA methylation analysis of CTCs is a promising new tool to potentially detect changes in tumor burden and monitor treatment response. Despite significant progress, analysis of DNA methylation in CTCs remains technically challenging. In this project we used novel size-based microfilter to enrich for CTCs with subsequent methylation analysis of nine genes known to be hypermethylated in breast cancer. Metastatic breast cancer patients (n=37) were recruited from the Division of Oncology at the Medical University of Graz. As a control group, 25 healthy individuals were included in this study. From each patient blood was drawn and CTCs were enriched using microfilter. For healthy individuals, mononuclear cells (MNCs) were isolated. Subsequently, CTCs and MNCs were subjected to methylation analysis using pyrosequencing. A 9-gene panel was used to determine methylation status of CTCs and MNCs. We successfully evaluated the feasibility of the novel size-based microfilter and methylation analysis of CTCs in metastatic breast cancer patients. Results of the clinical validation indicate that the nine genes were differentially methylated. In total, 48.6% of all patients showed hypermethylation in at least one gene. The varying frequency and level of methylation reflects heterogeneity within breast cancer. Analysis of MNCs from 25 healthy controls revealed that 97% were unmethylated. This proves the clinical specificity of our method. In this study we demonstrate the feasibility of a novel size-based microfilter to enrich and analyze multigene methylation profiles of CTCs. The results of this study show that we established an informative panel of biomarkers for the analysis of DNA methylation levels in CTCs.

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