ERG and prostate intraepithelial neoplasia: Loss of PTEN expression has been strongly associated with prostate cancer progression (Koksal et al, 2004; Bertram et al, 2006; Yoshimoto et al, 2006a; Schmitz et al, 2007) and has recently been implicated as cooperating with TMPRSS2–ERG fusion in high-grade prostatic intraepithelial neoplasia (Carver et al, 2009; King et al, 2009).