MMP9 and metastatic malignant neoplasm in the lymph nodes: In several tumor entities, MMP-2 and MMP-9 are described as protumorigenic MMPs, associated with lymph node metastasis and poor outcome 36, 37, and MMP-9 might also function protective in specific situations 38 Both, MMP-2 and -9, are capable of cleaving collagen-4, a major component of the BM 39, 40.