Figure 5: Mutations observed in the PI3KCA and p85α. The amino acids residues show mutations in the indicated protein domains. A. Hot spot mutations of PI3KCA in HNSCC are E545K/G/K and p.H1047R/L as indicted in orange boxes. B. The site of mutations of regulatory subunit PIK3R1 (also known as p85α) are found within the RhoGAP-binding domain and the iSH2 domain.