INSM1 and adenocarcinoma: To this end, we performed IHC staining on prostate tissues from 8-week old intact mice and found that while prostates from PR mice were composed of AR-positive, HGPIN lesions, tumors from PRN mice contained large regions of AR-positive adenocarcinoma, as well as neighboring foci comprised of AR-negative, INSM1-positive cells (Fig. 3a).