Despite the conflicting literature surrounding the pro- or antitumorigenic role of TLR9 in prostate cancer, and consistent with the ability of CPG-ODNs to act as immunostimulatory adjuvants for vaccines [79], our study provides support for the idea that systemic stimulation of TLR9 reduces the growth of orthotopic tumors in vivo by boosting systemic innate immunity. This evidence concerns the gene TLR9 and prostate cancer.