As predicted by the corresponding patient data (Fig. 1a, b and Supplementary Fig. 1a–d), TMPRSS2-ERG overexpression together with Trp53 deletion induced focal low-grade prostatic intraepithelial neoplasia (PIN), a precursor of cancerous lesions in the prostate of Pb-T2-ERG;Trp53pc-/- mice as early as 10 months of age (Supplementary Fig. 2a, b) and high-grade PIN (HGPIN) and focal adenocarcinoma in approximately 50% of 15 month-old mice (Fig. 1c, d). This evidence concerns the gene TMPRSS2 and prostate intraepithelial neoplasia.