TLR9 and neoplasm: For instance, DMXAA (5,6-Dimethylxanthenone-4-acetic acid), an agonist for the STING pathway, demonstrates a high affinity for murine STING but not for its human counterpart.625 This disparity could explain the largely suboptimal performance of DMXAA in early clinical trials for tumor treatments.236 Another illustrative example is the differential potency among various TLR9 agonists.