In addition to significant differences in Tiam1 expression between benign and premalignant (i.e. HG-PIN) or benign and malignant prostatic epithelial cells (i.e. cancer), respectively, we also observed differences in Tiam1 expression between normal non-epithelial cells, including inflammatory cells, fibromuscular stromal cells, and ganglion cells. The gene discussed is TIAM1; the disease is prostate intraepithelial neoplasia.