The latter process is essential for the delivery of nutrients to the proliferating cancer cells and for furnishing the structural support for tumour expansion.[26,27] MMPs do not act synergically during tumourigenesis: the up-regulation of MMP-2 and MMP-9 is associated with the degradation of the ECM and the BM, and with an increase in tumour aggressiveness; the down-regulation of MMP-13 is associated with a worsening of the disease prognosis; and that of MMP-7, with an increase in tumour invasiveness. The gene discussed is MMP9; the disease is neoplasm.