For example, we and others have shown that PI3K signaling drives a common escape pathway for EGFR inhibitor resistant tumors and that combinations targeting both EGFR and PI3K are highly synergistic in HNSCC models and tumors.12, 13, 14, 15, 16, 17, 18, 19. Here, EGFR is linked to head and neck squamous cell carcinoma.