It is defined as one of the “oncomiRs”, the cancer-promoting miRNAs, and has been documented to target several tumour suppressor genes (such as PTEN, RHOB, PDCD4, TIMP3) and play a role in signalling pathways (RAS/MEK/ERK, PTEN/PI3K/AKT, and Wnt/β-catenin). This evidence concerns the gene PTEN and cancer.