title: A summary for molecular regulations of miRNAs in breast cancer.
abstract: BACKGROUND
  Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death among women worldwide. MicroRNAs (miRNAs) are naturally-occurring, non-coding small RNA molecules that can modulate protein coding-genes, which makes it contributing to nearly all the physiological and pathological processes. Progression of breast cancer and resistance to endocrine therapies have been attributed to the possibility of hormone-responsive miRNAs involved in the regulation of certain signaling pathways.
  
  
  METHODS
  This review introduces better understanding of miRNAs to provide promising advances for treatment. miRNAs have multiple targets, and they were found to regulate different signaling pathways; consequently it is important to characterize their mechanisms of action and their cellular targets in order to introduce miRNAs as novel and promising therapies.
  
  
  RESULTS
  This review summarizes the molecular mechanisms of miRNAs in TGF-beta signaling, apoptosis, metastasis, cell cycle, ER-signaling, and drug resistance.
  
  
  CONCLUSIONS
  Finally, miRNAs will be introduced as promising molecules to be used in the fight against breast cancer and its developed drug resistance.
authors.affiliation: Hormones Department, Medical Division, National Research Centre, Dokki, Cairo, Egypt.
authors.forename: Shaymaa M M
authors.initials: SM
authors.lastname: Yahya
authors.affiliation: Hormones Department, Medical Division, National Research Centre, Dokki, Cairo, Egypt. Electronic address: ghadanrc@yahoo.com.
authors.forename: Ghada H
authors.initials: GH
authors.lastname: Elsayed
mesh_terms: D000818:Animals; D017209:Apoptosis; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009362:Neoplasm Metastasis; D016212:Transforming Growth Factor beta / Q000502:physiology
chemical_list: D035683:MicroRNAs; D016212:Transforming Growth Factor beta
keywords: Breast cancer; Cell cycle; Drug resistance; Metastasis; miRNA