PIK3CA and head and neck squamous cell carcinoma: In addition to validating previously reported genetic alterations in HNSCC, such as CCND1, MYC, EGFR, ERBB2, and CCNE1 amplifications, CDKN2A deletions, and TP53, CDKN2A, HRAS, PTEN, and PIK3CA mutations [38], this study implicated many genes which were previously unrecognized to be important players in HNSCC.