The role of oncomirs in the pathogenesis and treatment of breast cancer.

Breast cancer, the most common cancer among women, is a heterogeneous and complex disease, which detail of its precise progression mechanisms is less understood. So, an improved comprehension of the precise molecular mechanisms leading to disease progression and design of effective targeted therapies are required for patients with breast cancer. MicroRNAs demonstrate an uncovered class of small and endogenous non-coding RNAs and play an important role in the normal biological processes, including cell differentiation, proliferation and apoptosis. Some miRNAs, known as oncomiR, show different expression levels in cancer and are capable to effect on cellular transformation, carcinogenesis and metastasis and are characterized by high expression levels in tumors compared to normal tissues. Therefore, oncomiRs can be considered as prognostic biomarkers and therapeutic targets in different types of cancers. Moreover, the utilization of oncomiRs as therapeutic targets for cancer is promising. Accordingly, there is evidence which implies an important role of various oncogenic microRNAs in immunopathogenesis of breast cancer. In this review we will discuss about the role of various oncomiRs such as miR-21, miR-155, miR-10b, and miR-221/222 in the pathogenesis and treatment of breast cancer.