In particular, overactivation of this pathway via PTEN loss significantly favors initiation of PCa (Di Cristofano et al., 1998; Suzuki et al., 1998; Podsypanina et al., 1999), and leads to constitutive activation of the PI3K pathway in 60% of CRPCs (Vivanco and Sawyers, 2002). The gene discussed is PIK3CB; the disease is posterior cortical atrophy.