Breast cancer MicroRNAs: Clinical biomarkers for the diagnosis and treatment strategies

Breast cancer is the second most common cancer in females that accounts for the highest cancer-specific deaths worldwide. Although recent advances in clinical management significantly reduced the mortality rate in breast cancer patients, the success rate of the effective therapy remains largely dependent on early detection. It has been demonstrated that gene expression profile may be a useful tool to define the signature of breast cancer as well as to predict the prognosis or response to treatment. The microRNA expression profile is gaining lots of attention to define various types of cancers since they play critical roles in many different cellular processes including metabolism, apoptosis, differentiation, and development. Several studies have shown that microRNA's signatures are associated with the staging, progression, and response to treatment in breast cancer. In addition to this microRNA has been shown to act as oncogenes and tumor suppressor genes. Continued efforts to delineate the microRNA function in mammary physiological and pathological conditions will reveal novel insights into normal cells and breast cancer biology and ultimately provide a new molecular target for alternate therapy. The book chapter covers the role of microRNAs in the diagnosis, staging, progression, prognosis, and response to treatment of breast cancer.