Since we have established a direct functional link between cystatin C and Erk2 activity, and we have demonstrated that PCa patients with low cystatin C levels and concomitant high levels of AR showed a tendency towards a worse outcome as compared to patients with high cystatin C and high AR levels, we therefore wanted to assess the cellular and molecular association between cystatin C and AR. Here, MAPK1 is linked to posterior cortical atrophy.