title: Integrated miRNA and mRNA profiling of tumor-educated macrophages identifies prognostic subgroups in estrogen receptor-positive breast cancer.
abstract: BACKGROUND
  Various studies have identified aberrantly expressed miRNAs in breast cancer and demonstrated an association between distinct miRNAs and malignant progression as well as metastasis. Even though tumor-associated macrophages (TAM) are known mediators of these processes, little is known regarding their miRNA expression upon education by malignant cells in vivo.
  
  
  METHODS
  We profiled miRNA and mRNA expression of in vitro tumor-educated macrophages (TEM) by indirectly co-culturing with estrogen-receptor-positive (ER+) MCF-7 breast cancer cells. The prognostic power of the resulting miRNA list was investigated in primary breast cancer datasets and compared to other signatures. Furthermore, miRNA expression levels were correlated to mRNA expression of macrophage markers and the impact on prognosis was assessed.
  
  
  RESULTS
  Through the evaluation of the group effects between differentially-expressed miRNAs and their target mRNAs in TEM, the power of detecting regulated miRNAs was greatly increased. The resulting list of 96 miRNAs predicts disease-free survival (DFS) in external datasets of ER+ breast cancer patients and performs well in comparison with other miRNA signatures. Clustering with the predefined miRNA list revealed a significant difference in survival between the two resulting patient groups. Furthermore, an optimized miRNA list, based on correlations with macrophages markers, proved even more capable at identifying patient clusters significantly differing in DFS.
  
  
  CONCLUSIONS
  In vitro profiling of TEM and subsequent bioinformatic verification identified miRNAs with a high prognostic power for DFS when transferred into the clinical setting of primary breast cancer. The resulting miRNAs not only verify previously established findings but also lead to new prognostic markers. Furthermore, our data suggest that TAM contribute to the total miRNA expression profile of ER + breast cancers.
authors.affiliation: Dept. of Hematology/Oncology, University Medical Center Göttingen, 37099 Göttingen, Germany; Dept. of Medical Statistics, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: a.bleckmann@med.uni-goettingen.de.
authors.forename: Annalen
authors.initials: A
authors.lastname: Bleckmann
authors.affiliation: Dept. of Medical Statistics, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: Andreas.Leha@med.uni-goettingen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Leha
authors.affiliation: Dept. of Medical Statistics, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: artmanns@student.ethz.ch.
authors.forename: Stephan
authors.initials: S
authors.lastname: Artmann
authors.affiliation: Dept. of Hematology/Oncology, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: Kerstin.Menck@med.uni-goettingen.de.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Menck
authors.affiliation: Dept. of Developmental Biochemistry, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: gsalina@gwdg.de.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Salinas-Riester
authors.affiliation: Dept. of Hematology/Oncology, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: claudia.binder@med.uni-goettingen.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Binder
authors.affiliation: Dept. of Hematology/Oncology, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: tobias.pukrop@med.uni-goettingen.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Pukrop
authors.affiliation: Dept. of Medical Statistics, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: Tim.Beissbarth@med.uni-goettingen.de.
authors.forename: Tim
authors.initials: T
authors.lastname: Beissbarth
authors.affiliation: Dept. of Hematology/Oncology, University Medical Center Göttingen, 37099 Göttingen, Germany. Electronic address: florian.klemm@med.uni-goettingen.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Klemm
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D018920:Coculture Techniques; D018572:Disease-Free Survival; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D061986:MCF-7 Cells; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D035683:MicroRNAs / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis*; D011960:Receptors, Estrogen; D015996:Survival Rate
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger; D011960:Receptors, Estrogen
keywords: Breast cancer; Tumor-associated macrophages; miRNA