STAT3 and neoplasm: Meanwhile, conjugating CpG motifs, the ligand for Toll-like receptor (TLR9), to oligonucleotides, including siRNA, antisense against STAT3, enables targeted in vivo delivery into TLR9-positive tumor-associated immune cells as well as tumor cells with elevated TLR expression, leading to potent antitumor effects through both antitumor immune responses and direct tumor cell killing (21, 22).