Dysregulation of mir-21 as a possible prognostic marker in aggressive breast cancer

Andia Seyedi moghaddam,1 Mahdieh salimi,2,* Hossein mozdarani ,3 Najmeh ranji,4 Parisa azimi nejadan,5

1. Department of Molecular Genetics,Rasht Azad University, Rasht, Iran
2. Department of Medical Genetics, Institute of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
3. Department of Medical Genetics, Tarbiat Modares University, Tehran, Iran
4. Department of Molecular Genetics, Rasht Azad University, Rasht, Iran
5. Department of General Surgery, Iran University of Medical Science, Tehran,Iran

Abstract

Introduction

Breast cancer is the most common cancer and leading cause of cancer death in women worldwide, accounting for 25.1% of all cancers. this cancer is strongly in asia, africa and south america is growing. micrornas (mirnas), a class of small (19–25 nt in length) single-stranded rnas, which regulates cell growth, development and differentiation. some mirnas are also classified as tumor suppressors and oncogenes. the gene of human microrna-21 is located on plus strand of chromosome 17q23.2 overlapping with a protein coding gene tmem49. the mir-21 is an oncogenic mirna associated with cancer. according to the recent current population reports, several target genes of mir-21 have been identified in humans including pten (phosphatase and tensin homolog deleted on chromosome 10). pten is a tumor suppressor gene, has identified the important role in cell cycle regulation and apoptosis through inhibiting the phosphatidylinositol 3-kinase/akt signaling pathway by removing the phosphate in d3-phosphate group of phosphoinositide-3, 4, 5-triphosphate (pip3). in breast cancer, the alteration of pten expression has been reported to correlate with aggressive breast cancer phenotype.

Methods

The level of mir-21 expression in breast tumours were compared with normal control using comparative real-time rt-pcr method.

Results

The data show, the expression of mir-21 in breast tumors is significantly higher than normal tissues which is related to the stage of tumors and the status of tumor hormonal receptors.

Conclusion

We can conclude that up regulation of mir-21 may be considered as a possible prognostic marker which is detectable in tissue via inhibition of pten. confirmation of this phenomenon may be promising in breast cancer management.

Keywords

Breast cancer, mir-21, biomarker, prognosis