The invention provides methods for detecting abnormal prostate conditions, such as benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN), and adenocarcinoma, in an animal by comparing the amount of the Breast Tumor Kinase (BRK) tyrosine kinase in the nuclei of prostate luminal epithelial cells in a test sample with an amount of nuclear BRK protein in epithelial cells of normal prostate glands.