The mutation frequencies of several tumor-suppressor genes including FAT1, CDKN2A, FGFR3, and CASP8 were lower in the HPV-positive group of HNSC, and even the mutation frequencies of FAT1, CDKN2A, and CASP8 were 0 (Supplementary Table S4), indicating that the biological processes regulated by these genes were not disrupted. This evidence concerns the gene CDKN2A and neoplasm.