In molecular biology mir-451 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by several mechanisms.
miR-451 regulates the drug-transporter protein P-glycoprotein, potentially promoting resistance to the chemotherapy drug Paclitaxel.
Mir-451 microRNA Wikipedia
A proof-of-concept experiment has shown that miR-451, as well as mir-126 and mir-150, could be using in forensic science to distinguish between blood and saliva samples. This is made possible by different miRNA profiles of miRNAs in the different tissue types.