Overexpression of microRNA-21 in the Serum of Breast Cancer Patients

Microrna. 2020;9(1):58-63. doi: 10.2174/2211536608666190318105757.


Background: Breast cancer is the most common cancer diagnosed in women worldwide. So it seems that there's a good chance of recovery if it's detected in its early stages even before the appearances of symptoms. Recent studies have shown that miRNAs play an important role during cancer progression. These transcripts can be tracked in liquid samples to reveal if cancer exists, for earlier treatment. MicroRNA-21 (miR-21) has been shown to be a key regulator of carcinogenesis, and breast tumor is no exception.

Objective: The present study was aimed to track the miR-21 expression level in serum of the breast cancer patients in comparison with that of normal counterparts.

Methods: Comparative real-time polymerase chain reaction was applied to determine the levels of expression of miR-21 in the serum samples of 57 participants from which, 42 were the patients with breast cancer including pre-surgery patients (n = 30) and post-surgery patients (n = 12), and the others were the healthy controls (n = 15).

Results: MiR-21 was significantly over expressed in the serum of breast cancer patients as compared with healthy controls (P = 0.002). A significant decrease was also observed following tumor resection (P < 0.0001). Moreover, it was found that miR-21 overexpression level was significantly associated with tumor grade (P = 0.004).

Conclusion: These findings suggest that miR-21 has the potential to be used as a novel breast cancer biomarker for early detection and prognosis, although further experiments are needed.

Keywords: Antigen; MiR-21; biomarkers; breast cancer; microRNA; serum..

MeSH terms

  • Biomarkers, Tumor / blood*
  • Biomarkers, Tumor / genetics
  • Breast Neoplasms / blood
  • Breast Neoplasms / genetics*
  • Disease Progression
  • Early Detection of Cancer / methods*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • MicroRNAs / blood*
  • MicroRNAs / genetics
  • Middle Aged
  • Real-Time Polymerase Chain Reaction


  • Biomarkers, Tumor
  • MIRN21 microRNA, human
  • MicroRNAs