The Oncogenic Role of miR-155 in Breast Cancer

miR-155 is an oncogenic miRNA with well described roles in leukemia. However, additional roles of miR-155 in breast cancer progression have recently been described. A thorough literature search was conducted to review all published data to date, examining the role of miR-155 in breast cancer. Data on all validated miR-155 target genes was collated to identify biologic pathways relevant to miR-155 and breast cancer progression. Publications describing the clinical relevance, functional characterization, and regulation of expression of miR-155 in the context of breast cancer are reviewed. A total of 147 validated miR-155 target genes were identified from the literature. Pathway analysis of these genes identified likely roles in apoptosis, differentiation, angiogenesis, proliferation, and epithelial mesenchymal transition. The large number of validated miR-155 targets presented here provide many avenues of interest as to the clinical potential of miR-155. Further investigation of these target genes will be required to elucidate the specific mechanisms and functions of miR-155 in breast cancer. This is the first review examining the role of miR-155 in breast cancer progression. The collated data of target genes and biologic pathways of miR-155 identified in this review suggest new avenues of research for this oncogenic miRNA. Cancer Epideiniol Biomarkers Prev; 21(8); 1236-43. (c) 2012 AACR.