MicroRNAs (MiRNAs) constitute 19-25 nulceotide, non-coding RNA that regulate the expression of target genes, mainly at the post-transcriptional level. Breast cancer (BC) is most common cause of death in women accounting for 522,000 in 2012.It has got poor prognosis. In this review, we aim to provide a comprehensive story on miRNA signatures of cancers specially breast cancer.