Whilst the incidence of high grade PIN in the prostates of Spry2−/− mice (25%) was significantly greater than in Spry2+/− mice (P < 0.01) and wild-type mice (P < 0.0001), the incidence of HGPIN in Spry2+/− (7%) was not significant when compared with wild type. The gene discussed is SPRY2; the disease is prostate intraepithelial neoplasia.