title: MiR-155 expression level changes might be associated with initial phases of breast cancer pathogenesis and lymph-node metastasis.
abstract: BACKGROUND
  Breast carcinoma is heterogeneous disease. Understanding the process of invasion and metastasis and the selection of the therapy for patients with breast carcinomas still remains difficult. MicroRNAs are powerful gene expression regulators. Because of inconsistent findings, we have analyzed potential difference in miR-155 levels in three breast cancer groups.
  
  
  OBJECTIVE
  Our goals were to examine miR-155 expression levels in normal tissue, non-invasive and invasive breast carcinomas, and their association with standard clinical and pathological parameters and oncomiR-21, and to investigate the ability of miR-155 to separate invasive breast carcinomas with non-invasive component from pure invasive.
  
  
  METHODS
  In the group of 40 breast tissue samples, relative expression levels of miR-155 were examined with stem-loop quantitative real-time PCR using TaqMan technology.
  
  
  RESULTS
  The significant difference among four examined groups of the breast tissue was detected (p = 0.001). In the group of pure invasive tumors, patients with positive nodal status had significantly higher miR-155 levels (p = 0.046).
  
  
  CONCLUSIONS
  Our results suggest that miR-155 might be involved in breast cancer pathogenesis and in tumor spreading to the lymph nodes, and that it might be used as biomarker for additional stratification of patients with invasive breast carcinomas with non-invasive component.
authors.affiliation: University of Belgrade-Vinča Institute of Nuclear Sciences, Mike Petrovića Alasa, Belgrade, Serbia.
authors.forename: Nina
authors.initials: N
authors.lastname: Petrović
authors.affiliation: University of Belgrade-Vinča Institute of Nuclear Sciences, Mike Petrovića Alasa, Belgrade, Serbia.
authors.forename: Ana
authors.initials: A
authors.lastname: Kolaković
authors.affiliation: University of Belgrade-Vinča Institute of Nuclear Sciences, Mike Petrovića Alasa, Belgrade, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Stanković
authors.affiliation: Institute for Oncology and Radiology of Serbia, Belgrade, Serbia.
authors.forename: Silvana
authors.initials: S
authors.lastname: Lukić
authors.affiliation: University of Belgrade-Vinča Institute of Nuclear Sciences, Mike Petrovića Alasa, Belgrade, Serbia.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Řami
authors.affiliation: University of Belgrade-Vinča Institute of Nuclear Sciences, Mike Petrovića Alasa, Belgrade, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Ivković
authors.affiliation: University of Belgrade-Vinča Institute of Nuclear Sciences, Mike Petrovića Alasa, Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Mandušić
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D063646:Carcinogenesis / Q000235:genetics*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000235:genetics* / Q000473:pathology; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D009361:Neoplasm Invasiveness / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C524942:MIRN155 microRNA, human; D035683:MicroRNAs
keywords: breast cancer,; miR-155,; microRNA expression levels