Investigative and extrapolative role of microRNAs' genetic expression in breast carcinoma

MicroRNAs (miRs) are non-coding ribonucleic acids consisting of about 18-22 nucleotide bases. Expression of several miRs can be altered in breast carcinomas in comparison to healthy breast tissue, or between various subtypes of breast cancer. These are regulated as either oncogene or tumor suppressors, this shows that their expression is misrepresented in cancers. Some miRs are specifically associated with breast cancer and are affected by cancer-restricted signaling pathways e.g. downstream of estrogen receptor-α or HER2/neu. Connection of multiple miRs with breast cancer, and the fact that most of these post transcript structures may transform complex functional networks of mRNAs, identify them as potential investigative, extrapolative and predictive tumor markers, as well as possible targets for treatment. Investigative tools that are currently available are RNA-based molecular techniques. An additional advantage related to miRs in oncology is that they are remarkably stable and are notably detectable in serum and plasma. Literature search was performed by using database of PubMed, the keywords used were microRNA (52 searches) AND breast cancer (169 searches). PERN was used by database of Bahria University, this included literature and articles from international sources; 2 articles from Pakistan on this topic were consulted (one in international journal and one in a local journal). Of these, 49 articles were shortlisted which discussed relation of microRNA genetic expression in breast cancer. These articles were consulted for this review.