Middleton, et al. [12] also used histologically normal prostate samples from patients undergoing radical prostatectomy as controls and demonstrated the stromal signaling molecules bone morphogenetic protein 5 (BMP5) and CXC chemokine ligand 13 (CXCL13) are enriched in BPH specimens while estrogen regulated pathways were depleted. This evidence concerns the gene BMP5 and benign prostatic hyperplasia.