ERG and prostate cancer: Tomlins et al (2005) identified the overexpression of ERG (21q22.3) and ETV1 (7p21.2) in prostate cancer tumour cells after DNA fusion with a prostate-specific gene, TMPRSS2. ERG and ETV1 proteins are members of the ETS family of transcription factors, which are important in several oncogenic pathways (Watson et al, 2002; Seth and Watson, 2005). The TMPRSS2 protein is a serine protease that is highly expressed in both normal and cancerous prostate cells, and expression is regulated by androgens (Lin et al, 1999; Afar et al, 2001).