TLR9 and neoplasm: Cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN) can stimulate dendritic cells, B cells, macrophages to produce pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and activate the innate immune system by interacting with Toll-like receptor 9 (TLR9) to enhance anti-tumor activity [102–104].