PIK3CA and head and neck squamous cell carcinoma: Lui et al reported 12.6% mutations of PIK3CA in HNSCC (46/151), which was substantially fewer than the number reported by TCGA (in total 21%, 58/279 cases, including: 32/279, 11.7% of E545K/E542K mutations and 26/279, 9.3% of H4047R mutation) [9].