TDRD1 and Familial prostate cancer: DETG analysis between 21 in-frame TMPRSS2-ERG positive samples versus 471 fusion-negative samples yielded only two up-regulated target genes: ERG and TDRD1. Previous transcriptional profiling studies have shown that ERG knockdown in TMPRSS2-ERG positive prostate cancer cell-lines leads to decreased expression of genes that are typically overexpressed in PRAD as compared to prostatic intraepithelial neoplasia [36].