The TMPRSS2-ERG gene fusion resulting in ERG overexpression has been found in around 50% of prostate cancers (PCa) and is a very early event in tumorigenesis.    ///     The TMPRSS2-ERG gene fusion resulting in ERG overexpression has been found in around 50% of prostate cancers (PCa) and is a very early event in tumorigenesis. 