MMP9 and metastatic malignant neoplasm in the lymph nodes: The MMP family contains 24 members, of which MMP-2 (gelatinase A, 72-kDa type IV collagenase) and gelatinase B (92-kDa type IV collagenase) have been observed in several cancers including breast cancer, colon cancer, skin cancer and lung cancer [33-37] and their expression has been correlated with local invasion by the tumor, lymph node metastasis and survival rate [31-34,38,39].