PDCD4 protein expression increased after LNCaP and PC-3 cells were transfected with the miR-21 inhibitor (Fig 2b) (PC-3 cells: Z = −3.920, P < 0.001; LNCaP cells: Z = 3.883, P < 0.001), suggesting that PDCD4 is regulated by miR-21 in these prostate cancer cell lines. The gene discussed is PDCD4; the disease is prostate cancer.