PIK3CA and head and neck squamous cell carcinoma: Waterfall plot depicted the mutational landscape of the top 20 genes of mutation frequency in HNSCC patients, including TTN, TP53, FAT1, CDKN2A, MUC16, CSMD3, etc. Further comparison of the mutation frequency of KMGs between the two subgroups found that there was significant difference in TP53, MUC16, PIK3CA, NOTCH1, and SYNE1.