PKA also phosphorylates the Thr89 residue in HSP90, leading to the release of AR from HSP90 and the binding of AR to HSP27, which transfers AR into the nucleus to transactivate its targets [91]. In addition, PKA signaling pathway is involved in the neuroendocrine differentiation of prostate cancer, an early marker for the development of androgen independence [92, 93]. This evidence concerns the gene AR and Familial prostate cancer.