Background and aims: Breast cancer is the most common cancer among women. miRNAs are a class of non-coding RNAs which play an important role in control of gene expression at
post-transcriptional level. miR-126, an intronic miRNA derived from EGFL7 gene. miR-126 has been revealed to down-regulate and play a tumor suppressive role in breast tumors. The aim of this study was to assess the expression of miR-126 in breast and normal tissue and an association between these data and age of Iranian population.
Methods: In this study, expression of miR-126 was assessed in cancer specimen and normal breast tissues by Real Time RT-PCR. Then, the association between expression of miR-126 and age were calculated. U6 gene was selected as the control. Data were analyzed statstically by ANOVA and t- test.
Results: Data indicated that the expression of miR-126 was significantly down-regulated in tumor status. Also, the expression of miR-126 had a significantly difference between normal and malignant and benign tumor. (P<0.05). In addition, there was a relationship between age and the expression of miR-126, and the age of the patients who had a low expression of miR-126 was less than the age of  the patients that had the high expression of miR-126.
Conclusion: The results shows that miR-126 expression decreases in tumor status. In addition, a significant correlation between expression of miR-126 and age of patients was observed