Mirna21 Expression in the Breast Cancer Tumor Tissue is Independent of Neoadjuvant Chemotherapy

Abstract

Introduction

MicroRNA-21 (miRNA-21) has been described as one of the most significantly upregulated miRNAs in human breast cancer. However, limited knowledge exists on miRNA-21 expression in breast cancer tissue after neoadjuvant chemotherapy (NAC).

Purpose

The aim of this study was to assess miRNA-21 expression in the tumor tissues of Brazilian patients with breast cancer who underwent NAC and its correlation with clinicopathological variables.

Patients and Methods

Utilizing qRT-PCR, miRNA-21 expression in tumor tissue was measured in a cohort of female patients with breast cancer who underwent NAC. The correlation of miRNA-21 expression with breast cancer molecular subtypes and other clinicopathological variables was also assessed.

Results

A total of 55 patients were included in the study, and 28 (50.9%) underwent NAC. miRNA-21 was upregulated in patients with breast cancer, regardless of previous exposure to chemotherapy, molecular subtypes, tumor-node-metastasis (TNM) staging and lymph node status of the axilla. miRNA-21 expression did not differ between patients with breast cancer who achieved a pathologic complete response after NAC and healthy controls.

Conclusion

miRNA-21 was upregulated in the tumor tissue of Brazilian patients with breast cancer regardless of NAC treatment, which reinforces its role as an “oncomiR” and a potential biomarker.

Keywords:

• miRNA-21
• breast cancer
• biomarker
• tumor tissue
• neoadjuvant chemotherapy

Abbreviations

PCR, pathological complete response; NAC, neoadjuvant chemotherapy; Naïve, chemotherapy naïve; NST, invasive carcinoma of no special type; ILC, invasive lobular carcinoma; HER-2, HER-2 overexpression; TNM, tumor-node-metastasis breast cancer staging.

Author Contributions

All authors made a significant contribution to the reported work, whether in the conception, study design, execution, data acquisition, analysis and interpretation, or in all of these areas. In addition, the authors collaborated with the writing, critical review of the article and gave the final approval of the version to be published. After reviewing this study, all authors agreed with the journal to which the article was submitted; and agree to be responsible for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work. The authors also report no financial interest with this study.