Down-regulation of the miRNA master regulators Drosha and Dicer is associated with specific subgroups of breast cancer

Eur J Cancer. 2011 Jan;47(1):138-50. doi: 10.1016/j.ejca.2010.08.007. Epub 2010 Sep 9.


Down-regulation of Drosha and Dicer has been suggested to be of prognostic value in some cancers. The aims of our study were to investigate the down-regulation of Drosha and Dicer in breast cancers and its associations with clinicopathological features, molecular subtypes and outcome. Drosha and Dicer expression was assessed with real-time RT-PCR in 245 patients with breast cancer receiving adjuvant anthracycline-based chemotherapy and compared to expression levels of normal breast tissue. Drosha down-regulation was observed in 18% of cases and was associated with high grade, high Ki-67, lack of Bcl2 expression, HER2 over-expression and gene amplification and TOPO2A gene amplification. Dicer down-regulation was found in 46% of cases and was associated with lack of expression of ER, PR and Bcl2 and with high grade, high Ki-67, triple-negative and basal-like phenotypes. Drosha and Dicer were concurrently down-regulated in 15% of cases and significantly associated with high grade and high Ki-67 index. No significant associations between down-regulation of Drosha and/or Dicer and outcome were observed. Our results suggest that down-regulation of Drosha and/or Dicer is not robustly associated with the outcome of breast cancer patients treated with adjuvant anthracycline-based chemotherapy but preferentially observed in distinct subgroups of breast cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthracyclines / therapeutic use
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Biomarkers, Tumor / metabolism*
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Chemotherapy, Adjuvant
  • DEAD-box RNA Helicases / metabolism*
  • Down-Regulation
  • Female
  • Humans
  • Immunohistochemistry
  • Kaplan-Meier Estimate
  • MicroRNAs / metabolism*
  • Ribonuclease III / metabolism*


  • Anthracyclines
  • Biomarkers, Tumor
  • MicroRNAs
  • DICER1 protein, human
  • DROSHA protein, human
  • Ribonuclease III
  • DEAD-box RNA Helicases