MMP9 and colorectal carcinoma: Furthermore, NF-κB is constitutively activated in human CRC cells and is associated with cell progression [15,16], cell growth by inhibiting apoptosis [17], cell migration and invasion [18], cell metastasis by regulating matrix metalloproteinase-9 [19] and cell promotion by regulating cyclooxygenase-2 [20], which collectively may help mediate chemoresistance and radioresistance of tumor cells [21].