TLR4 and cervical cancer: The 3D (6-acyl)-PHAD is a synthetic compound, SyMPL (Fig. 1), which acts as a potent stimulator of TLR4 and is similar in structure and function to the active ingredient in adjuvants like GSK’s AS0x series of adjuvants included in the approved cervical cancer vaccine Cervarix® and the shingles vaccine Shingrix®.