In the efferent pathway, cancer cells release soluble factors such as TGF-β and platelet-derived growth factor (PDGF) that cause changes within the stroma and activate it, known as a reactive response, whereas in the afferent pathway, cancer cells respond to and are influenced by the reactive stroma [119] towards the development of prostatic intraepithelial neoplasia (PIN) [120,121,122]. The gene discussed is TGFB1; the disease is cancer.