PIK3CA and head and neck squamous cell carcinoma: Enhanced PI3K signaling has been implicated in HNSCC tumorigenesis; however, the role of PI3K pathway activation by PIK3CA mutations in HPV(+) OPSCC needs to be further explored since AKT was not activated by mutant PIK3CA in the presence of HPV oncoproteins [58, 85, 86].