TNF and melanoma: In this regard, Exo enter the lymphatic vessels and are captured into the lymph nodes where it induces the expression of pro-angiogenic factors, including tumor necrosis factor (TNF)-α, VEGF, hypoxia-inducible factor (HIF)-1, and a urokinase plasminogen activator, which enhances the subsequent trapping and growth of melanoma cells [38,39].