RT Journal Article SR Electronic T1 MicroRNA involvement in the pathogenesis and management of breast cancer JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 422 OP 428 DO 10.1136/jcp.2008.060681 VO 62 IS 5 A1 Khoshnaw, S M A1 Green, A R A1 Powe, D G A1 Ellis, I O YR 2009 UL http://jcp.bmj.com/content/62/5/422.abstract AB MicroRNAs (miRNAs) are a highly abundant class of endogenous small non-coding RNAs (18–25 nucleotides in length) that regulate gene expression by targeting protein-coding mRNAs post-transcriptionally. miRNAs have been implicated in cancer development and progression. As miRNAs and their regulatory functions are further revealed, the more the importance of miRNA-directed gene regulation is emphasised. In the human genome, 695 mature miRNAs have been identified, although computational calculation predicts that this may increase to >1000. Deregulation of miRNA expression profiles is thought to be implicated in the pathogenesis of many human cancers including breast tumours. Breast cancer subtypes are observed to have deranged miRNA expression signatures, which makes miRNAs important targets for developing a novel molecular classification of breast cancer and opening avenues for more individualised treatment strategies for patients with breast cancer.