Abstract
BACKGROUND: The most common cancer in women is breast cancer (BC). MicroRNA-21 was one of the first oncomiRs to be found at elevated levels in a number of malignancies, including gliomas, BC, and colorectal cancer (miR-21). MiRNA is associated with processes such as apoptosis, invasion, metastasis, and proliferation, which are known features of cancer. This study aimed to investigate the molecular basis and clinical significance of miR-21 in BC, as microRNAs play a critical role in this disease. MATERIALS AND METHODS: MiR 21 was then analyzed by the quantitative polymerase chain reaction (qPCR) using the Taq-Man probe. The thermal profile included 5 min of denaturation at 95°C, then 40 cycles of denaturation at 95°C for 20 s, annealing at 52°C for 20 s, and extension at 72°C for 30 s. Two separate runs of real-time polymerase chain reaction and reverse transcription (RT) were then performed. Relative quantification of the gene expression levels (fold change) based on computed tomography values was used to examine the data from RT-qPCR for miR-21 and Glyceraldehyde-3-phosphate dehydrogenase (Livak and Schmittgen). RESULTS: The mean fold change in serum miR-21 levels was significantly higher in cases (8.17 ± 2.49) than in controls (1.02 ± 0.23). The mean fold change in serum miR-21 levels in Stages III, IV and lymph nodes were significantly higher than in Stages I and II. The mean fold change in serum miR-21 gene expression was significant with the changes in different Ki67 levels. CONCLUSIONS: Our results demonstrate the importance of miR-21 plasma level as a diagnostic and prognostic biomarker for BC.