Homa Baghbani - Department of Genetics, Faculty of Sciences Shahid Chamran University of Ahvaz, Ahvaz, Iran
Hosseinali Sasan - Department of Biology, Faculty of Science Shahid Bahonar University of Kerman, Kerman, Iran
Reza Kazemi Nezhad - Department of Genetics, Faculty of Sciences Shahid Chamran University of Ahvaz, Ahvaz, Iran
Mohamad Reza Hajari - Department of Genetics, Faculty of Sciences Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract Background: Cancer is the second leading cause of death, after cardiovascular diseases worldwide. Breast cancer is the most diagnosed non-skin cancer and the second leading cause of cancer death in women in the USA. MicroRNAs are small RNA molecules that play critical roles in many different cellular processes such as differentiation, proliferation, and apoptosis by post transcriptional regulation of genes. Hence, aberrant microRNA expression is common in a variety of disorders, including cancer. It is well established that miR-21 expression promotes proliferation and invasiveness of breast cancer cells. MiR-21 is considered a key oncogene miRNA in carcinogenesis since its expression is consistently high in a wide range of cancers including Breast cancer. In this study the level of expression of mir-21 gene was evaluated in new cases of women breast cancer in stage 3 and stage 2. Materials and Methods: 5 ml of blood was sampled from 40 affected women with age between around 35 to 60 years using of K3-EDTA 6 ml sterile tubes. Plasma was isolated from all blood 40 samples and stored at −80°C.Total RNAs was extracted by RNXplus procedures. PolyA segment was added in 3ˊ region RNA using of poly(A) polymerase enzyme and cDNA was synthesized using of Fermentas kit. In the last stage expression of mir-21 gene was detected via Real time PCR experiments. Then, the real time data was analyzed by Rest software. Results: the results show that changes of expression of mir-21 gene in breast cancer in grade 3 than grade 2 is not significant. Conclusion: By results of this study it can be suggested that whit Development breast cancer expression of mir-21 Dose not change much.

Breast cancer, Women, Stage, MicroRNA, Mir-21, Real time