PIAS1 and posterior cortical atrophy: However, PIAS1 knockdown in PC-3 and DU145 cells did not significantly affect the proliferation and migration capabilities of these PCa cells (Supplemental Figure 3, B and C), nor did it affect the tumor formation of PC-3 cells in CDX models (Supplemental Figure 3D), suggesting that PIAS1 may not be a major tumor suppressor or promoter under normal physiological conditions.