In both recurrence and non-recurrence groups from patients with HNSCC who had previously received definitive surgery and adjuvant radiotherapy, high phosphorylation levels of PI3K, AKT, mTOR, eukaryotic initiation factor 4E (eIF4E), and eIF4E binding protein 1 (4EBP1) were observed [24,25]. Here, MTOR is linked to head and neck squamous cell carcinoma.