Background: microRNAs (miRNAs) have been highlighted as potential circulating biomarkers and therapeutic targets for breast cancer (BC). miRNAs have emerged as an extremely promising new class of biomarkers. They have been demonstrated to be remarkably stable in human blood. miR-155 has more than 4 hundred predicted gene targets. The miR-155 plays an essential role in the pathogenesis of breast cancer. The aim of this study was to assess the diagnostic value of miR-155 expression in the serum of patients with breast cancer according to the molecular subtypes of BC.

Introduction The recurrence of breast cancer (BC) is a major cause of cancer death in females. Reduction in miR-126 expression, as a tumor suppressor gene, would conduct to a pro-angiogenic effect. The aim of our study was to examine association of the miR-126 rs4636297 with the recurrence of BC. Materials and Methods:The present study was done on 424 females with BC (102 patients with the recurrence of BC, as the case group, and 322 women without any recurrence of BC, as the control group). After DNA extraction from peripheral blood, genotyping was done using Tetra Arms PCR Technique. Thereafter, the genotype and allele frequency of miR-126 rs4636297 was compared between the two groups. Results:The results were shown that there was no significant association between miR-126 rs4636297 polymorphism with BC recurrence. Conclusions: Thus, miR-126 rs4636297 polymorphism is not associated with the susceptibility of BC recurrence.

Background: Breast cancer (BC) is an illness affecting millions of women across the world. The transition from ductal carcinoma in situ to invasive ductal breast cancer is a crucial event in the progress that is still not well understood. microRNAs (miRNAs) have recently been documented to play an important role in cancer development. miRNAs have been discovered to control this critical transition. The miR-155 plays an essential role in the pathogenesis of breast cancer. miR-155 has been implicated in developing breast cancer. Objectives: This study aimed to investigate the expression of miR-155 in the serum of patients with breast cancer, according to clinical characteristics (DCIS and IDC) of breast cancer. Methods: 60 patients referring to hospitals in Ahvaz during 2012 and 2015 were divided into 2 groups according to clinical characteristics (DCIS and IDC). miRNA was extracted, and complementary DNA (cDNA) was synthesized in line with the guidelines of the Kit manufacturer. A real-time PCR method was performed as the expression assay. Results: The mean expression level of miR-155 in DCIS group was 6.45 ± 0.545. In addition, the mean expression level of miR-155 in serum of DCI group was 40.42 ± 0.742; the difference was statistically significant (P < 0.0001). Conclusions: Based on the results of this study, the serum level of miR-155 evidenced a statistically significant difference in invasive breast cancer (IDC) patients. The study results showed that checking the serum level of miR-155 expression in patients with invasive breast cancer (IDC) might be helpful.