TLR4 was verified to protect the tumor from immune attack in HNSC/OSCC.30, 31, 32 In the present study, TLR4 ligand LPS35 was shown to promote the carcinogenesis of mouse tongue leukoplakia by increasing IFITM4P and PD-L1 levels. This evidence concerns the gene IFITM4P and leukoplakia of tongue.