NOS1 and melanoma: To investigate the role of NOS1-downregulation of IFN signaling in the metastasis of melanoma, we successfully constructed an animal model of melanoma lung metastasis by injecting B16F10-(Control/Over-NOS1) cells into C57BL/6 mice via the tail vein and sacrificed mice on the 11th day after injection to count the number of lung nodules.