MAPK3 and benign prostatic hyperplasia: In contrast, in BPH-1 cells co-cultured with wild-type fibroblasts, finasteride repressed the expression of p-AKT (1.21 versus 0.33, P < 0.001), p-ERK1/2 (1.16 versus 0.21, P < 0.001), and cyclin D1 (0.82 versus 0.16, P < 0.001).