Using ERG expression by IHC as a genetically validated proxy for ERG rearrangement status (35), we were able to corroborate this finding in the JHU primary tumor cohort (P < 0.0001; Fig. 4A) with a similar trend in a separate independent primary tumor cohort from the PCBN (P = 0.05; Fig. 4B). This evidence concerns the gene ERG and neoplasm.