sentences:  Mice genetically modified so that they could not produce TLR4 molecules showed normal cancer growth.Toll-like receptor 4 has been shown to be important for the long-term side-effects of opioid analgesic drugs.Various μ-opioid receptor ligands have been tested and found to also possess action as agonists or antagonists of TLR4, with opioid agonists such as morphine being TLR4 agonists, while opioid antagonists such as naloxone were found to be TLR4 antagonists.