Norgen’s Urine Total RNA Purification Maxi Kit (Slurry Format) provides a rapid method for the isolation and purification of total RNA from 5 – 10 mL of urine. The kit purifies all sizes of RNA, from large mRNA and ribosomal RNA down to small RNAs. These small RNAs include regulatory RNA molecules such as microRNA (miRNA) as well as tRNA and 5S rRNA. Small RNA molecules are often studied due to their ability to regulate gene expression. miRNAs are typically 20-25 nucleotides long, and regulate gene expression by binding to mRNA molecules and affecting their stability or translation. Several recent studies showed that miRNA regulates cell growth and apoptosis. Furthermore, clinical and experimental analyses suggested that miRNAs may function as a novel class of oncogenes or tumor suppressor genes. MicroRNA expression profiles of different tumor types, relative to their normal tissues, have recently been shown to provide phenotypic signatures for particular cancer types. Unique patterns of aberrant miRNA expression may serve as molecular biomarkers for tumor diagnosis, prognosis of disease specific outcomes, and prediction of therapeutic responses.