Silencing of PLAU1 inhibited the proliferation, colony-formation, migration, and invasion abilities of HNSCC cells in vitro and reduced the expression of matrix metalloproteinase 1 (MMP1), whereas PLAU1 overexpression significantly enhanced the growth, the colony-formation, migration, and invasion abilities, and the xenograft tumor growth of HNSCC cells in vivo and increased the expression of MMP1. Here, MMP1 is linked to neoplasm.