ERG and pachyonychia congenita: The fusion of the transmembrane protease serine 2 gene with the erythroblast transformation-specific-related gene (TMPRSS2:ERG) on chromosome 21 is the most recurrent genomic alteration in aggressive localized PC, as well as ERG translocations (commons in the peripheral zone, but rare in the transitional zone of the prostate gland) and PTEN loss.