Among MMPs, MMP-2 and MMP-9 are collagenase that can selectively degrade type IV collagen, a major component of ECM; overexpression of MMP-2 or MMP-9 is associated with more lymph node metastases, distant metastases and poor survival in head and neck SCC (21–24). This evidence concerns the gene MMP2 and metastatic malignant neoplasm in the lymph nodes.