Fra-1 can increase the production of the cytokine IL-6 and skew RAW264.7 macrophage cell differentiation into M2d macrophage, then promotes tumor metastasis and progression (21, 103); CD137 promotes the migration of monocytes/macrophages to tumor microenvironment by upregulating the expression of Fra1. Here, TNFRSF9 is linked to neoplasm.