PLK1 and neoplasm: To determine the therapeutic effects of our combined miR-34a and PLK1-siRNA treatment in vivo, tumor-bearing mice were randomized into four nanoparticle treatment groups: (i) miR-34a/PLK1-siRNA, (ii) miR-34a/NC-siRNA, (iii) PLK1-siRNA/NC-miR, and (iv) NC-miR/NC-siRNA, and a group treated with PBS (n = 6/7 mice per group).