CD47 increased expression is positively correlated with the movement of melanoma cells toward metastasis and its blockade suppresses the metastasis through enhancing the abilities of macrophages and the number of differentiated macrophages (by 50%) in the pulmonary sites of metastasis, declining the expression of Nos2 mRNA, and stimulating the expression of key enzymes involving during NO synthesis [98]. This evidence concerns the gene NOS2 and melanoma.