Expression and function of miR-155 in breast cancer

A major problem in the treatment of breast cancer at present is the lack of more sensitive and specific tumour biomarkers. MicroRNAs (miRNAs) were first discovered as important regulators of development in Caenorhabditis elegans, and their functions have been widely investigated. miR-155 is an oncogenic miRNA which has been explored mainly in leukaemia but is also known to play an important role in the progression of breast cancer. There is an accumulating body of evidence about additional roles of miR-155 in the development of breast cancer. In this mini-review, we provide an overview and update of miR-155 expression and its roles in breast cancer. We also attempt to summarize the current understanding of miR-155 regulation networks and speculate on the potential of miR-155 as a putative accessory parameter for diagnosis of breast cancer.