The observation that a broad-spectrum MMP inhibitor (marimastat, BB2516), known to affect tumor invasion, inhibits also growth of head and neck squamous cell carcinoma (HNSCC) cells that overexpress EGFR, highlighted the MMP role (e.g., MMP9) in cleaving HER ligands from membrane-anchored precursors into their functionally activated states (218a). This evidence concerns the gene MMP9 and head and neck squamous cell carcinoma.