TY - GEN A1 - Kammerer, Sarah A1 - Sokolowski, Armin Andreas A1 - Hackl, Hubert A1 - Platzer, Dieter A1 - Jahn, Stephan Wenzel A1 - El-Heliebi, Amin A1 - Schwarzenbacher, Daniela A1 - Stiegelbauer, Verena A1 - Pichler, Martin A1 - Rezania, Simin A1 - Fiegl, Heidelinde A1 - Peintinger, Florentia A1 - Regitnig, Peter A1 - Höfler, Gerald A1 - Schreibmayer, Wolfgang A1 - Bauernhofer, Thomas T1 - KCNJ3 is a new independent prognostic marker for estrogen receptor positive breast cancer patients T2 - OncoTarget : open access impact journal N2 - Numerous studies showed abnormal expression of ion channels in different cancer types. Amongst these, the potassium channel gene KCNJ3 (encoding for GIRK1 proteins) has been reported to be upregulated in tumors of patients with breast cancer and to correlate with positive lymph node status. We aimed to study KCNJ3 levels in different breast cancer subtypes using gene expression data from the TCGA, to validate our findings using RNA in situ hybridization in a validation cohort (GEO ID GSE17705), and to study the prognostic value of KCNJ3using survival analysis. In a total of > 1000 breast cancer patients of two independent data sets we showed a) that KCNJ3 expression is upregulated in tumor tissue compared to corresponding normal tissue (p < 0.001), b) that KCNJ3 expression is associated with estrogen receptor (ER) positive tumors (p < 0.001), but that KCNJ3 expression is variable within this group, and c) that ER positive patients with high KCNJ3 levels have worse overall (p < 0.05) and disease free survival probabilities (p < 0.01), whereby KCNJ3 is an independent prognostic factor (p <0.05). In conclusion, our data suggest that patients with ER positive breast cancer might be stratified into high risk and low risk groups based on the KCNJ3 levels in the tumor. Y1 - 2016 U6 - https://doi.org/10.18632/oncotarget.13224 VL - 7 IS - 51 SP - 84705 EP - 84717 ER -