ERG and prostate cancer: On the other hand, several studies have demonstrated that deletion of the chr 21q22.2-22.3 genomic region and more specifically deletions of the interstitial genes between the androgen-regulated gene TMPRSS2 and the ETS transcription factor family member ERG leads to the generation of a TMPRSS2-ERG fusion gene that promotes prostate cancer progression [31,32,33].