Several recent genomic studies now establish PCa as best being regarded as a collection of molecularly defined cancers -similar to breast and lung cancer- with major subclasses defined by either ETS gene fusions (most commonly TMPRSS2-ERG rearrangements), SPOP or FOXA1 single-nucleotide mutations1, 9, 10. The gene discussed is ERG; the disease is posterior cortical atrophy.