VEGFA and melanoma: An example is VEGF,52 which acts directly to promote new blood vessel growth, and secretion of TNF-α and IL-1α, which act indirectly to drive the secretion of pro-angiogenic factors by melanoma cells.53 Aside from angiogenesis, macrophages promote melanoma progression, as evidenced by their increased density at the invasive front of melanoma lesions,54,55 and promote metastasis.