MMP9 and cancer: Since NGAL is endowed with pleiotropic properties that range from the control of cell proliferation and survival to the enhancement of MMP-9 enzymatic activity through preservation of its auto-degradation, it is not surprising that its expression has been found altered in malignant tumors arising from different tissues such as breast, pancreas, colon, thyroid, liver, ovary, endometrium, lung, esophagus, stomach, bile ducts, prostate and skin [23].