TLR3 and cancer: TLR agonists approved by the FDA for the treatment in cancer patients include Bacillus Calmette-Guérin (BCG) (activates TLR2, TLR3, TLR4 and TLR9), monophosphoryl lipid (MPL) (TLR4 agonist) and imiquimod (TLR7 agonist) [117,118,119].