MMP2 is responsible for extracellular matrix (ECM) digestion and VEGF proteolytic release from the tumour matrix 26, 36; therefore, the reduced expression of MMP2 found in AQP1 KD tumours might also reduce the amount of the available VEGF necessary to induce a normal level of tumour angiogenesis. The gene discussed is AQP1; the disease is neoplasm.