A qRT-PCR analysis performed to detect TMPRSS2: ERG gene rearrangement in a retrospective series of n = 19 PCa patients (n = 11 prebiopsy and n = 8 pre-radical prostatectomy samples, respectively) revealed that 8 out of 19 (42.0%) PCa patients showed a detectable TMPRSS2: ERG aberrant gene fusion expression. The gene discussed is ERG; the disease is posterior cortical atrophy.