TNF and melanoma: By utilizing a recently developed melanoma cell and M2 macrophage coculture model6 (Fig. 4i), we revealed that the M2-differentiated THP1 cells could promote the proliferation of WM3918 cells (Fig. 4j, k), whereas TNFα blocking antibody could largely suppress THP1 coculture-induced WM3918 proliferation (Supplementary Fig. 7k, l).