miRNAs have been shown to regulate many developmental and physiological processes, and the deregulation of miRNAs has been linked to a number of disease processes, including cancer. miRNAs play important roles in fine-tuning gene expression regulators referred to as “dimmer switches” because of their ability to repress gene expression without completely silencing it.  The precise monitoring of miRNA expression particularly in cell-based assay, can help to reveal the potential miRNA impacts on cancer etiology, differential stages and therapy development.  Signosis developed the miRNA target reporter vectors.  Each target reporter vector was constructed by inserting miRNA 3’UTR (~1kb) as corresponding miRNA binding sites on the downstream of luciferase reporter gene.  When miRNA in cells binds to the target site at 3'UTR downstream of reporter luciferase gene, it leads to repression of the expression of luciferase and results in reduction of luciferase enzyme activity. The miRNA expression level quantitatively corresponds with the luciferase activities.