Our earlier studies have shown that reactive stroma initiates at foci of early premalignant prostatic intraepithelial neoplasia (PIN) in human prostate gland and co-evolves with the development of carcinoma and expression of transforming growth factor beta 1 (TGF-β1) in PIN epithelium [3], [4]. The gene discussed is TGFB1; the disease is carcinoma.