TLR7 and actinic keratosis: The TLR7 ligand Imiquimod has been approved by the US Food and Drug Administration (FDA) for the treatment of actinic keratosis, external genital/perianal warts (condylomata acuminata), and superficial basal cell carcinoma, and is in clinical studies for other cancers, as is the TLR8 agonist Motolimod [38].