Several mechanisms reported previously by ourselves and others may contribute to the reactivation of AR in CYP17 inhibitor-resistant PCa, including increased intratumoral steroid synthesis [8, 9], selection for progesterone-driven T878A mutation of AR [10], and activation of ErbB2 pathway that stabilizes AR protein [11, 12]. This evidence concerns the gene CYP17A1 and posterior cortical atrophy.