TLR9 and cancer: Nucleotide- or deoxynucleotide-based adjuvants (unmethylated CpG deoxynucleotides [CpG ODN]24–26, a TLR9 agonist, and polyincosinic-polycytidylic acid [Poly I:C]27, 28, a TLR3 agonist ) are currently used for cancer immunotherapy.