PIK3CA and head and neck squamous cell carcinoma: Dysregulation of phosphatidylinositol 3-kinase (PI3K) signaling has been a molecular target in both human papilloma virus (HPV)-positive and HPV-negative head and neck squamous cell carcinomas as it is the most frequently altered oncogenic pathway in these neoplasms, in part brought about by PI3KCA gain-of-function mutations [13,50,51,52,53,54,55].