Recurrent gene fusions between TMPRSS2 (transmembrane protease serine 2) and the gene ERG, a member of the transcription factor erythroblastosis virus E26 transforming sequence family (ETS), are highly specific to PCa and can be found in up to 40-50% of prostate carcinomas [12–14]. The gene discussed is TMPRSS2; the disease is posterior cortical atrophy.