PTEN protein synthesis is negatively regulated by microRNAs miR-26A1 and miR-26A2, which recruit the RISC complex to PTEN mRNA. Overexpression of miR-26A2, caused by genomic amplification of MIR26A2 locus on chromosome 12, is frequently observed in human brain glioma tumors possessing one wild-type PTEN allele, and is thought to contribute to tumor progression by repressing PTEN protein expression from the remaining allele (Huse et al. 2009). Other microRNAs, which may also be altered in cancer, such as miR-17, miR-19a, miR-19b, miR-20a, miR-20b, miR-21, miR-22, miR-25, miR-93, miR-106a, miR-106b, miR 205, and miR 214, also bind PTEN mRNA and inhibit its translation into protein (Meng et al. 2007, Xiao et al. 2008, Yang et al. 2008, Kim et al. 2010, Poliseno, Salmena, Riccardi et al. 2010, Zhang et al. 2010, Tay et al. 2011, Qu et al. 2012, Cai et al. 2013).