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Selected Publication:

Sokolowski, A.
Expression of genes coding for G protein-coupled inwardly-rectifying potassium channels (GIRKs) in breast cancer
Humanmedizin; [ Diplomarbeit ] Medical University of Graz; 2014. pp. 115 [OPEN ACCESS]


Authors Med Uni Graz:
Sokolowski Armin
Bauernhofer Thomas
Schreibmayer Wolfgang

Background Among the many molecular players in cancer, G-protein coupled receptors have recently been identified to play an important role in the process of cancer progression and metastasis. GIRK1 protein, known for being overexpressed in breast cancer tissue, and a high GIRK1 mRNA expression have been shown to correlate with lymph node metastases in studies with small patient numbers. The aim of this study was to validate these findings by analyzing GIRK1 mRNA expression using large breast cancer patient sets. Methods The GIRK1 mRNA expression levels of 914 invasive breast carcinoma samples available at TCGA were downloaded from the cBio portal with the corresponding clinical data from the UCSC Cancer Genomics Browser. In addition, mRNA expression levels of 105 healthy tissue samples corresponding to 105 of the patients mentioned above were downloaded from the TCGA Data Portal. The mRNA data and the clinical data were combined in Microsoft Excel 2010® and the further analysis was performed in SigmaPlot v12.5®. Results Analysis of the TCGA data showed that GIRK1 is significantly overexpressed in breast cancer compared to normal tissue (p<0.001). Furthermore, GIRK1 expression is significantly higher in estrogen receptor positive tumors (p<0.001) and in lymph node positive tumors (p<0.001) than in estrogen receptor negative and lymph node negative tumors, respectively. Survival analysis of the TCGA data set showed that the hazard rate is significantly affected by GIRK1 mRNA expression (p<0.034). Conclusion Our analysis of TCGA data indicates that GIRK1 overexpression is associated with lymph node positive as well as with estrogen receptor positive breast cancer and confirms previous findings. In addition we could show that GIRK1 overexpression has a negative effect on the overall survival, especially in estrogen receptor positive breast cancer.

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