AMACR and prostate carcinoma: Patients would be classified into 4 different diagnosis categories according to the staining results: 1) benign lesion (P504s negative/P63 positive); 2) prostate cancer (P504s positive/P63 negative); 3) high-grade prostatic intraepithelial (HGPIN) or atypical adenomatous hyperplasia (AAH, P504s positive/P63 positive); and 4) atypical small acinar proliferation, suspected to be malignant (ASAP, P504s negative/P63 negative) (8).