# Dysregulation of miR-577, miR-505-3p, miR-3682-3p, and miR-4661 in Breast Cancer Patients Based on Estrogen Receptor Status: Dysregulation of miRNAs in Breast Cancer Patients Based on ER Status

## TL;DR

This study identifies specific microRNAs that are dysregulated in breast cancer, particularly in estrogen receptor-positive cases, suggesting potential diagnostic biomarkers.

## Contribution

The study identifies novel miRNA biomarkers for breast cancer diagnosis, specifically in ER+ and ER- subtypes.

## Key findings

- miR-577 and miR-505-3p are significantly downregulated in ER+ breast cancer samples.
- miR-3682-3p and miR-4661-5p are upregulated in cancer tissues compared to normal tissues.
- miR-577 and miR-505-3p show strong diagnostic potential for breast cancer detection.

## Abstract

Breast cancer is one of the most common malignancies and the second leading cause of cancer-related death in women. Approximately 75% of all breast cancers are estrogen receptor-positive (ER+) and highly responsive to endocrine therapy. MicroRNAs (miRNAs) are short non-coding RNA with a pivotal role in mammal cells by regulating gene expression. Hence, this study aimed to evaluate the miRNAs expression in various breast cancer subtypes.

In this study, after total RNA extraction and cDNA synthesis, expressions of miR-577, miR-505-3p, miR-3682-3p, and miR-4661-5p were investigated in 36 breast cancer samples of ER+ and ER- types and compared with 18 normal adjacent tissues by real-time polymerase chain reaction. Also, diagnostic values of miRNAs were determined based on receiver operating characteristic (ROC) by calculating the area under the curve (AUC).

Downregulation of miR-577 and miR-505-3p were detected in breast cancer samples, significantly in the ER+ subtype compared to ER- subtype (P0.001). Also, we showed upregulation of miR-3682-3p and miR-4661-5p in breast cancer tissues compared to normal tissues. Compared to the ER+ subtype, the miR-3682-3p expression significantly decreased in the ER- subtype (P0.001). However, there was no significant difference between ER+ and ER- subtypes in the term of miR-4661-5p (P˃0.05). The ROC analysis demonstrated that miR-577 and miR-505-3p have acceptable diagnostic values, and miR-3682-3p has a relatively proper diagnostic value in diagnosing breast cancer.

Our results revealed that miR-577 and miR-505-3p could be used as biomarkers for the diagnosis of breast cancer, especially in ER+ subtype.