PIK3CA and head and neck squamous cell carcinoma: Unexpectedly, we found that the most of top‐10 mutated genes (TP53, TTN, FAT1, CDKN2A, NOTCH1, MUC16, CSMD3, LRP1B and PIK3CA) were the same and mutation frequency of them possessed unobvious difference in both groups (Figure 3A), which hinted that mutation frequency mentioned above nine genes play essential roles in HNSCC initiation and progression.