Prognostic implications of microRNA-21 overexpression in invasive ductal carcinomas of the breast

Jung Ah Lee, Hye Yoon Lee, Eun Sook Lee, Insun Kim, Jeoung Won Bae

Research output: Contribution to journalArticlepeer-review

64 Citations (Scopus)


Purpose: Among more than 500 microRNAs, microRNA-21 (miR-21) is known to act as an oncogene. The aim of this study was to investigate the signifcance of miR-21 expression level in relation with clinicopathological factors and prognosis in breast cancer. Methods: MicroRNA was extracted from cancer and normal breast tissue of 109 breast cancer patients who underwent surgery from 2002 to 2004 using the Taqman ® MicroRNA Assay. The correlation between miR-21 expression and clinicopathologic features was analyzed and the signifcance of miR-21 as a prognostic factor and its relationship with survival was determined. Results: MiR-21 expression was higher in cancer tissues than in normal tissues (p<0.0001). High miR-21 expression was associated with mastectomy, larger tumor size, higher stage, higher grade, estrogen receptor (ER) negative, human epidermal growth factor receptor 2 (HER2) positive, HER2 positive breast cancer subtype, high Ki-67 expression, and death. On multivariate analysis, prognostic factors for overall survival were ER and miR-21. High miR-21 expression was signifcantly related to lower overall survival (p=0.031). Conclusion: This study supports the role of miR-21 as an oncogene and a biomarker for breast cancer with its high expression in cancer tissues and its relationship with other prognostic factors and survival.

Original languageEnglish
Pages (from-to)269-275
Number of pages7
JournalJournal of Breast Cancer
Issue number4
Publication statusPublished - 2011 Dec
Externally publishedYes


  • Breast neoplasms
  • Human MicroRNA-21
  • Oncogene
  • Prognosis
  • Survival

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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