AQP1 and melanoma: AQP1 involvement in angiogenesis has been confirmed in other studies: in a murine melanoma tumour model, mice treated with AQP1 short interfering (si) RNA had significantly smaller tumours and lower microvessel and endothelial marker (factor VIII) densities compared to control mice, suggesting AQP1 knockdown impaired tumour growth and angiogenesis [11].