Dysregulation of miR-577, miR-505-3p, miR-3682-3p and miR-4661 in breast cancer patients, differentially expression in ER-positive compared to ER-negative

Abstract

It is proved that the breast cancer is one of the most common cancers and the second leading cause of cancer-related death in women. Approximately 75 % of all breast cancers is ER-positive which is highly responsive to endocrine therapy. MicroRNAs (miRNAs) are short non-coding RNA that have a pivotal role in mammal cells by regulating gene expression. The expression of miRNAs is different in the various subtypes of breast cancer, and the expression profile of miRNAs can be informative in the classification of breast cancer. In this study, after extraction of total RNA and synthesis of cDNA expression of miR-577, -505-3p, -3682-3p and -4661-5p were investigated respectively in eighteen breast cancer samples of both ER+ and ER- types and eighteen normal adjacent tissues by Real-Time PCR. Downregulation of miR-577 and miR-505-3p was detected in breast cancer samples. Expression of miR-577 and miR-505-3p significantly decreased in ER+ subtype compared to that of ER- subtype. Data has showed upregulation of miR-3682-3p and miR-4661-5p in breast cancer tissue. The expression level of this miRNA was higher in ER- subtype than that of the ER+ subtype. ROC analysis demonstrated that both miR-577 and miR-505-3p have an acceptable diagnostic value in diagnosing breast cancer and differentiation of various types of breast cancer. MiR-3682-3p has had a relatively proper diagnostic value in diagnosing breast cancer but it does not have adequate diagnostic power to discriminate the different subtypes of breast cancer. The data obtained from the present study revealed that both miR-577 and miR-505-3p could be used as a biomarker in diagnosing different subtypes of breast cancer.