PIK3CA and head and neck squamous cell carcinoma: We selected a total number of 19 genes, found to be significantly mutated in the TCGA HNSCC cohort: CDKN2A, FAT1, TP53, CASP8, AJUBA, PIK3CA, NOTCH1, KMT2D, NSD1, HLA-A, TGFBR2, HRAS, FBXW7, RB1, PIK3R1, TRAF3, NFE2L2, CUL3, and PTEN.