MMP9 and head and neck squamous cell carcinoma: Twelve genes were downregulated in HNSCC tissues compared with the levels in the surrounding normal tissues (LTF, PDK4, ELANE, HRC, BCL2L15, CEACAM5, CEACAM1, NTRK3, CRYAB, CCDC178, CLU, and F10), and 38 genes were upregulated (CAV1, BIRC5, TUBB3, CDH2, NTRK1, LAMB3, FADD, NOX4, CDC25C, UBE2C, ITGA6, CSPG4, FOXC2, IFI27, TNC, COL4A2, COL13A1, E2F1, AFP, MNX1, ITGA5, PLAU, BST2, SPP1, LAMA3, ADCY10, SERPINE1, FN1, SPINK1, PTHLH, CDKN2A, LAMC2, SLCO1B3, MMP9, ONECUT1, HOTAIR, MMP11, and MMP13) (Figs. 2B and 2C).