TLR9 and neoplasm: In our previous study, a TLR2 agonist recombinant lipoprotein combined with the TLR9 agonist CpG oligonucleotide (CpG ODN) could dramatically enhance antitumor efficacy and reduce the number of tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) [12].