Circulating MicroRNA-21 As A Promising Marker for Early Detection of Breast Cancer and Disease Progression in Egyptian Females

Abstract
Background: The traditional imaging techniques and the currently accepted markers such as serum CA15.3 have limited specificity and sensitivity to identify early stages breast cancer patients. MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level via mRNA degradation and/or translational repression. They can modulate up to 60% of protein-coding genes in the human genome, one of which is miRNA-21. MiRNA-21 and its alterations play critical roles in breast cancer.
Aim of Study: The study aimed at assessing the diagnostic and prognostic role of miRNA-21 in breast cancer females.
Subjects and Methods: This case-control study was con-ducted on (150) breast cancer female patients and their age matched (50) healthy controls. All subjects recruited in the present study were subjected to measurement of serum micro-RNA-21 expression using quantitative real time PCR (qRT-PCR) in comparison to serum CA15.3.
Results: Serum miRNA-21 expression is upregulated in breast cancer patients compared to controls (Z:4.4, p<0.01), with disease advanced TNMstages (H:24, p<0.001) and neg-ative estrogen receptor status (Z=2.2, p<0.05). At cut off level 1.07 (2–DDCt), miRNA-21 had 100% sensitivity and 90% specificity in discriminating patients with breast cancer from healthy controls. Meanwhile, CA15.3 had 70% sensitivity and 60% specificity in distinguishing between the two groups. At cut off level 3.33 (2–DD  Т) miRNA-21 expression had 86.7% sensitivity and 100% specificity in discriminating patients with early breast cancer from patients with advanced disease. While serum CA15.3 had 80% sensitivity and 86.7% specificity in discriminating between the same patients groups.
Conclusion: Serum miRNA-21 levels are significantly higher in breast cancer patients compared to healthy subjects. Increased miRNA-21 expression levels correlated with disease stages, estrogen receptor presence reflecting prognosis and influencing constructing treatment modalities.