PIK3CA and head and neck squamous cell carcinoma: Genomic analysis of 530 HNSCC patients in the TCGA database revealed that 97 cases (18.3%) harbored PIK3CA mutations, with the E542K, E545K, and H1047R/L variants accounting for 90% of the total mutations, highlighting their critical role in HNSCC pathogenesis [11,12,13].