ERG and prostate cancer: Analysis of fusion gene transcripts from prostate cancer patients by several investigators has shown the presence of multiple forms containing varying lengths of TMPRSS2 (promoter and exon 1 and 2) and ERG. The predominant form noted involves the fusion of TMPRSS2 exon 1 and ERG exon 4 (Tomlins nomenclature)/exon 8 (Owczarek nomenclature) [4, 16, 23].