The identification of fusion genes provides new insights into the initial mechanisms of molecular events implicated in the prostate cancer tumorigenesis. The presence of TEMPRSS2-ETS fusion in up to half of all human prostate cancer makes it perhaps the most common genetic rearrangement in human epithelial tumors. Some data suggest that TMPRSS2-ERG fusion prostate cancers have a more aggressive phenotype, which may affect cancer progression and outcome in localized tumors treated with prostatectomy. This discovery should pave the way towards future targeted therapies.