Recently, it was demonstrated that concomitant prostate-specific deletion of Spry1 and Spry2 in mice resulted in prostatic intraepithelial neoplasia (PIN), while deletion of either Spry 1 or Spry 2 in hemizygous Pten null mice resulted in invasive carcinoma [27]. The gene discussed is PTEN; the disease is prostate intraepithelial neoplasia.