RGS4 and posterior cortical atrophy: The increase, observed herein, in the expression of RGS4 in PC-3 cells after Poly E treatment reached a mean value of 17.11-fold (Figure 4H, high) and could suggest a role for RGS4 in attenuating GPCR-mediated cell proliferation in PC-3, and perhaps other in PCa cells as well.